AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: rich pierce on June 30, 2025, 05:15:17 PM
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Or is design, steel used, and heat treat the decider?
My vote: steel, design, and heat treat.
Nobody has ever made identical mainsprings using these 3 techniques and tested them to failure, so all your responses will be educated guesses - am I wrong?
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;D ;D ;D ;D
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I agree with whetrock! ;D
Actually, it could/should be a good discussion. With modern steel I'm not sure how it could be proved one way or another without some serious testing.
John
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Casting is an inferior process simply due to the propensity for defects, internal voids etc. After well over 10000 locks with machined springs and not one mainspring or frizzen spring breakage it has proven itself to be a wonderful process.
As far as the potential for a spring to take a set, this is universal with springs made from all processes if the material is too soft such that the yield strength is exceeded during lock function.
Grain direction at the bend makes ablsolutely no difference in this application. There is slight anisotropy in mechanical properties relative to grain direction but it is so small that it isn't significant.
I am a degreed metallurgist as well as a respected gunbuilder, but at times others think they know better about subjects such as this. Makes one wonder...
I'd be happy to debate any of these facts presented.
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Further, if you were to suggest using cast springs to any metallurgist or knowledgeable mechanical engineer they would become uncomfortable very quickly. The fact that they work as well as they do is really amazing in itself. If one has any education in this field the debate really is nonsensical.
To be perfectly honest, I don't think a machined or forged spring has any better properties in terms of lock function. I don't subscribe to the idea of the manufacture method contributing to "whippiness" etc. From a materials standpoint it doesn't make any sense. What determines the "feel" of the spring is the geometry. I would suggest that you could put a cast spring of the same size next to a machined and forged spring and probably feel no difference.
The advantages of machined springs are as follows:
Low chance of defects. Defects cause failure
High dimensional control, resulting in consistent strength, positioning in the lock etc.
One might also argue that a spring bent is a step up. I would counter that during the process of bending the spring the chance of introducing defects from overheating, bending too cold etc far outweigh the miniscule to nonexistent benefit of having grain flow wrap around the bend.
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I like data from experiments where only one variable changes - and it does change. Then outcomes are measured and compared statistically. I’m a published scientist with over 90 peer reviewed papers in medical journals. That’s how things are really tested.
Do I think machined springs are superior or inferior to cast or forged springs? No, because nobody has tested them head to head - same design, same steel, same heat treat, different ways of forming them - within the parameters needed for good flintlock function and flint life. Do I think forged springs are inferior or superior to machined or cast mainsprings? No, for the same reasons.
I’m betting many lock makers could share data on the reliability of their process. I’ve never had a mainspring break but that is simply anecdotal with many variables.
I don’t think that how they are formed - cast, forged, machined - is an issue.
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Further, if you were to suggest using cast springs to any metallurgist or knowledgeable mechanical engineer they would become uncomfortable very quickly. The fact that they work as well as they do is really amazing in itself. If one has any education in this field the debate really is nonsensical.
That’s what we call a hypothesis on their part.
They would probably also say that Bob Roller forging them essentially by hand from flat spring stock and quenching by eye and tempering by burning off in motor oil is a recipe for disaster. Don’t care what they say, who have not done the tests as I outline.
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I like data from experiments where only one variable changes - and it does change. Then outcomes are measured and compared statistically. I’m a published scientist with over 90 peer reviewed papers in medical journals. That’s how things are really tested.
Do I think machined springs are superior or inferior to cast or forged springs? No, because nobody has tested them head to head - same design, same steel, same heat treat, different ways of forming them - within the parameters needed for good flintlock function and flint life. Do I think forged springs are inferior or superior to machined or cast mainsprings? No, for the same reasons.
I’m betting many lock makers could share data on the reliability of their process. I’ve never had a mainspring break but that is simply anecdotal with many variables.
I don’t think that how they are formed - cast, forged, machined - is an issue.
Yes, it's always nice to test things head to head, but there also is proven widespread adopted positions in any field. In metallurgy and engineering one is that cast material is less reliable than forged material as a whole. The reason for this is the chance for defects. Defects cause failures. For example, would someone question and require testing to conclude that a forged or billet crankshaft is better than a cast one? This is accepted by everyone with half a brain. How about a lifting hook? Would anyone but a fool prefer a cast one? It really is this simple...
The debate between the benefits and weaknesses of casting versus forging, machining has been settled more than a century ago.
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For you motorheads, you think anyone building a performance engine would prefer cast connecting rods over billet machined ones? Ha! Guess the manufactures should do a side by side test to determine the truth ;). Silliness....
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Rich,
You might say this is "hypothesis", but as mentioned all of this has been sorted out LONG ago. You don't have to re-prove these principals based on every new part design or application. Just do a google search of properties of castings verses forgings. This should lead to some research articles. I'll dig into things and find references if necessary.
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4140 and others are better barrel steels than some being used today and superior to wrought iron forged barrels. That’s been settled since the invention of high pressure smokeless powder. Yet, somehow our fore bearers managed without it. So 4140 is “superior” - who cares? It’s irrelevant to me. It’s not going to make the gun shoot better with me behind it. Something can be factually sound and well-reasoned, and practically irrelevant. You’ve obviously made a good and well-reasoned choice that both fits your fabrication philosophy and practice and yields very reliable springs. That’s great! Nothing to prove to me until I own one. I handled one once. Very nice action. Love that “snick, snick” sound and feel when a cock is drawn to half then full cock. Love a frizzen that snaps open and snaps shut decisively, not sorta “well, guess I’ll go that way now.”
Oops I trolled the barrel steel devotees!
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Yeah, I've used lots of cast springs. I have no problem with them. I just find machined springs to work extremely well, have no breakage issues and can be manufactured to high tolerances. I'm in no way saying that cast springs aren't good or okay to use. I just find it laughable to suggest they are better than those machined from a billet, or to suggest that machined springs have issues and are not suitable (which was done in the other post). And if someone suggests this, I'd at least like to hear their reasoning why. Just saying something is meaningless. I try to have information to defend a position I take.
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Hey Rich thank you for starting this thread. I look forward to hearing what everyone has to say. Especially those who have been making these springs for decades.
We all know what Jim K thinks. Anyone else out there care to share? Thanks in advance.
CE
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Chris,
I am asking for your reasoning to believe cast springs are superior to those machined from billet material. Could you provide this information? I have defended my position, I'm still waiting for you to do the same. Otherwise they are just words, which have little value.
If you disagree with anything I've said, please express what this is and why.
Jim
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Jim,
I never said that cast springs are superior. I did say that I like forged springs better than cast springs.
In fact in my Ditchburn post I said that I'd never say no to machined springs either.
CE
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Here is your comment:
Right now the only thing I lack on the Ditchburn/Beck lock is the mainspring. I've been working on a few ways of going about making them but haven't settled on which option to use yet.
I don't want to do a milled mainspring as there are problems with these types of springs taking a "set" and losing strength.
So I've been working on several different ways of producing a cost effective forged spring. So far I have some good springs, but the "cost effective" element has eluded me. There are still a few things left to try so as time permits in the shop I'll be continuing to work this all out.
In this comment you make the assertation that milled mainsprings have problems taking a "set" and losing strength. I assume you don't believe cast springs have this perceived issue. Is this correct? Isn't it therefore reasonalble to conclude that you believe cast springs are superior? If this is too big of a step, I retract my statement.
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I see an unsetting attitude here, that somebody feels he always needs to be right.....
John
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John,
Are you directing this towards me? If so, should I interpret this as a personal attack?
Let me remind you, I've taken a great deal of time defending my statements. I welcome honest well intended debate. Actually I hope it happens! If I end up being wrong, I probably won't like it, but will certainly accept it. Those who know me well will agree.
Here's the truth... I am careful what I say and I absolutely HATE when people make comments related to our business that have no basis.
I don't think anyone who "thinks they are always right" could have successfully built a business like our in such a short amount of time. We are constantly asking ourselves if there are better ways or what we can do better, whether that is manufacturing, customer service, how we treat our employees etc.
Another example, I was designing the Germanic lock a while back. I sent it to a very knowledgeable friend and mentor. He said it sucked it a number of ways and described why. I didn't like it but took it and made the changes.
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Jim, I don't see where I mentioned your name, or your business! Period!
If you think I aimed it at you, consider why you might think such a thing.
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Jim, I don't see where I mentioned your name, or your business! Period!
If you think I aimed it at you, consider why you might think such a thing.
Well, I stand corrected ;D
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It was possibly aimed at me hahahaha. Not the first time, if so. And probably well-deserved! No sweat.
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I would assume that the biggest reason for casting springs is ease of manufacturing, especially if you're selling on un-finished springs.
Not everyone has access to a CNC mill, but almost anyone can cast a piece.
The question is then if a cast spring is 'good enough'.
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Yeah they are good enough! The tens of thousands produced has answered this question.
Are there options I think are better. Yes! This is why we machine them.
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Yeah they are good enough! The tens of thousands produced has answered this question.
Are there options I think are better. Yes! This is why we machine them.
I asked if a cast spring were 'good enough'....
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I answered the following:
Yes they are good enough. Read my post above again. In case it was ambiguous, I was referring to cast springs.
In case you or anyone else has missed my point, I have no issue with cast springs. I have an issue with the suggestion that machined springs don’t work well or that cast springs are better. Does this make sense? If you care to, read my posts and you’ll find this has been my consistent message.
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Apologies. misread it.
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In this comment you make the assertation that milled mainsprings have problems taking a "set" and losing strength. I assume you don't believe cast springs have this perceived issue. Is this correct? Isn't it therefore reasonalble to conclude that you believe cast springs are superior? If this is too big of a step, I retract my statement.
No it isn't a reasonable conclusion. Yes you are reaching. A lot. I accept your retraction.
CE
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Well good. Want to chat about your belief that machined springs take a set?
Help me out…. So you believe machined springs take a set, but are still as good as cast? Am I understanding this correctly?
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Hi,
Jim, why can't you lighten the mainsprings on your round-faced locks? I had a gentleman in my shop a few weeks ago who had one from your fowler kit and he could not pull the cock back with the lock out of the stock. We measured the force and it took 18lbs to pull the lock back from rest to full cock. He could not get more than 5 or 6 shots from a flint French amber, or black English, bevel up or bevel down. He is one of almost a dozen shooters with Woodsrunners and Colonial rifles in the past year coming to my shop with the same problem. I've only encountered forces nearly that strong on original military muskets. None of my original English sporting guns are even close to that including the one you owned. Anyway, I solved their issues by thinning the lower leaf of the mainsprings such that the force was reduced to 11-12lbs. I adjusted the feather springs accordingly. I did not touch the thickness of the bend, which is substantially thicker on your springs than any others. That solved their problems and they are all very happy with their guns. Why do they have to be so heavy?
dave
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Because I think it works best at this strength. I don’t subscribe to your beliefs about lock springs and the desired weights. I interact with dozens of customers a week and they generally report excellent results. Ask the most knowledgeable student of locks today (Frank House) his opinion of our locks. Don’t think they will match yours. Or how about the recent endorsements from Jud Brennan recently. He has used some locks recently and gave the compliment that he has to rebuild other lock brands but has to do nothing to ours. I know who to respect and value their opinion.
If you’ve even spent a little time studying original work, you’ll find springs of the strength we use are not uncommon. Dare I say that they are quite common, particularly on Continental pieces.
You like weak springs and slow locks where the flint lasts forever. I prefer a fast performance lock even if the flint has shorter life.
So that's why I make them as I do. The nice thing about owning a business is I get to make the decisions. I think our success is in direct correlation to how we please our customers.
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So I have smartdog saying our springs are too strong and I have Evrard saying they are too weak and take a set… I’m confused 🫤
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MY WELDER BROTHER USED TO SAY" YOU NEVER KNOW HOW GOOD THE WELD HAS TO BE, BUT WHEN IT FAILS YOU THEN KNOW WHEN ITS NOT GOOD ENOUGH!!!! AN OLD METALETGIST ONCE TOLD ME THAT WHEN STEEL( WROUGHT IRON METAL) WAS USED FOR IMPLEMENTS( KNIVES PLOWS ETC) THE FORGING PROCESS USED THE GRAIN STRUCTURE OF THE METAL FOR MORE STRENGTH!!!! TODAYS MILLED STEEL HAS NO NATURAL GRAIN STRUCTURE, SO TO HIM FORGING VS THE STOCK REMOVAL PROCESS PRODUCED THE SAME GRAIN STRUCTURE AFTER HEAT TREATING.. BASICALLY HIS ADVISED WAS TO EACH THEIR OWN... MY MONEY IS ON "JIM"....
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Jim you are to be commended in producing 10K quality locks in a short period of time.
However I would be more impressed if one of your locks had been fired in a gun 10,000 times.
In my experience shooting muzzleloaders, the average ML shooter shoots but once a month. On average 20 to 25 shots in a shoot., Only a percentage of those shoot every month.
Even when I was shooting competitively. That is four times a month with at least two times a month in competition, I only managed about 125 shots a month. On an average year I would manage to shoot 10 to 11 months .
So it would have taken me roughly 10 years to shoot 10,000 rounds though any particular gun.
The average shooter would take take roughly 40 years to shoot that many rounds in any particular gun.
My point is that on average amuzzleloader lock isn't going to be cycled enough to make a difference.
Competitive shooters with modern firearms who shoot many thousand shots a year do experience parts failures.
It would be interesting to do thermo mechanical fatigue testing on the three types of spring manufacturing mentioned to see what the actual failure rate would be for each.
But for the most part it isn't necessary.
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I agree that 10000 cycles of our locks would be interesting. I have no idea how many one of our locks has seen, but I would guess around 5000 or more. I’ve thought about fixturing one in a CNC machine and programming it to cycle the lock repeatedly, but the desire has never seemed great enough to justify the work.
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I am not really in the game now but I preferred forged springs but used a bunch of cast frizzen springs and so far so good.
Bob Roller
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So I have smartdog saying our springs are too strong and I have Evrard saying they are too weak and take a set… I’m confused 🫤
Go back and look at my post again. I never said your springs were too weak. I never mentioned you at all. I never said where my experience came from. This is very on purpose.
I was taught not to disparage other people's work. Just to do the best work you can and let that speak for itself.
CE
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So who else machines lock springs. I detect some squirming…
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Hi Jim,
I did not accuse you of malfeasance. I simply asked why the springs are so strong. So why are they so strong. What is the reason? I have folks coming in to my shop who are not happy with them so help them out.
dave
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To even a casual observer, it would appear as this was an attempt to pile on. I didn’t realize our spring strength was relevant to the thread title or current discussion.
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Jim, I have a question about the manufacturing of billet steel. I'm totally ignorant to the processes. My question, Is Billet not cast to create the piece? I realize it is then rolled to shape, does the rolling press out the voids making it more uniform? Interesting stuff, I would enjoy having you in the boat all day while fishing just to learn. Thanks,
Bob
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So who else machines lock springs. I detect some squirming…
Another thing I was taught was not to make personal attacks.
CE
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Not a lock maker, but common sense kinda tells me that a forged spring would probably have less imperfections than a cast one. I know that cast frizzen springs break from experience.
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Bill my buddy!!! I’d never guessed you would come to my defense!
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Or is design, steel used, and heat treat the decider?
My vote: steel, design, and heat treat.
Nobody has ever made identical mainsprings using these 3 techniques and tested them to failure, so all your responses will be educated guesses - am I wrong?
The times I've replaced a cast mainspring I forged out the replacement, but they were never identical to the cast spring. They almost certainly used different steels, were forged to suit my ideas on how a spring should be tapered, and heat-treated the way I've learned to do them over the years. I suspect comparing identical springs made in these three ways would be a comparison of the design as much as the method of manufacture.
Jim you are to be commended in producing 10K quality locks in a short period of time.
However I would be more impressed if one of your locks had been fired in a gun 10,000 times.
Here's one data point: In '23 I bought a Colonial to use in the "Intro to Flintlocks" classes I do. Since then,between shots fired by >200 students (plus at least 3 dry fires by each), use as a "loaner"/spare rifle at matches and by shooters who just wanted to try it out, and my own practice/experimentation/plinking, it has been fired or dry-fired at least 10,398 times.
So far, no parts failures. Subjectively, the springs seem as "snappy" as ever and the rate of flint use hasn't changed over time. If something breaks, I'll fix it and move on. If I ever have to replace a spring it will probably be forged: not because I think it is superior but because I'm not set up to cast or machine springs. I've only handled 3 other similar Kibler locks. Springs on all seemed about the same. I did have to slightly tweak the sear spring on the rifle I fit a single-set trigger to.
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Bill my buddy!!! I’d never guessed you would come to my defense!
Jim, I think our issues are merely how we go about things. Many roads to Rome and I often just take the long way....With that said, your products are not sent out willy nilly. In fact I see you as a guy that is ever seeking to build a good product.
Are your frizzen springs forged/machined also, or are they cast?....Do you know how the old L&R springs are made?...are they casted?
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Or is design, steel used, and heat treat the decider?
My vote: steel, design, and heat treat.
Nobody has ever made identical mainsprings using these 3 techniques and tested them to failure, so all your responses will be educated guesses - am I wrong?
The times I've replaced a cast mainspring I forged out the replacement, but they were never identical to the cast spring. They almost certainly used different steels, were forged to suit my ideas on how a spring should be tapered, and heat-treated the way I've learned to do them over the years. I suspect comparing identical springs made in these three ways would be a comparison of the design as much as the method of manufacture.
Jim you are to be commended in producing 10K quality locks in a short period of time.
However I would be more impressed if one of your locks had been fired in a gun 10,000 times.
Here's one data point: In '23 I bought a Colonial to use in the "Intro to Flintlocks" classes I do. Since then,between shots fired by >200 students (plus at least 3 dry fires by each), use as a "loaner"/spare rifle at matches and by shooters who just wanted to try it out, and my own practice/experimentation/plinking, it has been fired or dry-fired at least 10,398 times.
So far, no parts failures. Subjectively, the springs seem as "snappy" as ever and the rate of flint use hasn't changed over time. If something breaks, I'll fix it and move on. If I ever have to replace a spring it will probably be forged: not because I think it is superior but because I'm not set up to cast or machine springs. I've only handled 3 other similar Kibler locks. Springs on all seemed about the same. I did have to slightly tweak the sear spring on the rifle I fit a single-set trigger to.
Wow! Thanks so much for this post. It is reassuring in a time like this! This really pleases me.
All the best,
Jim
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As a professor in manufacturing processes, I’ve always leaned toward forged springs over cast due to their superior grain flow/structure and toughness. That said, I’d take a machined spring, like the ones Jim Kibler produces, over a cast one any day. The precision of machining, along with the ability to quickly tweak designs without revising molds or managing casting schedules with outside companies, makes it a better choice from a manufacturing perspective, at least at the scale we are talking about here.
In terms of function, there’s probably not a nickel’s worth of difference between well-made springs of any type. But Jim’s approach offers real advantages over the other processes in terms of consistency, scalability, and ease of production—qualities I would be looking at if I was doing what he is.
Jim, if you're ever in the mood for an experiment, I’d love to get a couple of our automation students involved in designing a lock testing machine. It’d be fascinating to cycle one of your locks 10,000 or even 50,000 times and see how it holds up. Could make for a great hands-on project—and some interesting data.
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Just saying, Jim, that as much as I believe in the quality of your products (and I do!), I really think the way you interact with people who have the slightest criticism of your products, isn't doing you any favours at all.
I for one, will not be buying any of your products after your recent spat here.
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Like me or not that’s fine. The general belief today is that you shouldn’t question others, the customer is always right etc. I don’t subscribe to this. Truth or what I believe to be the truth is what guides me in these interactions.
One thing that we believe has helped us grow a thriving business is authenticity. Whether you can believe it or not, we are very kind, but we won’t be walked on and if you’re full of $#*& we’ll call you on it. These are principles we live by and won’t be changing soon even if it should mean fewer customers. Personally, I think this honesty, though admittedly coarse at times has helped us gain trust with our customers.
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As a professor in manufacturing processes, I’ve always leaned toward forged springs over cast due to their superior grain flow/structure and toughness. That said, I’d take a machined spring, like the ones Jim Kibler produces, over a cast one any day. The precision of machining, along with the ability to quickly tweak designs without revising molds or managing casting schedules with outside companies, makes it a better choice from a manufacturing perspective, at least at the scale we are talking about here.
In terms of function, there’s probably not a nickel’s worth of difference between well-made springs of any type. But Jim’s approach offers real advantages over the other processes in terms of consistency, scalability, and ease of production—qualities I would be looking at if I was doing what he is.
Jim, if you're ever in the mood for an experiment, I’d love to get a couple of our automation students involved in designing a lock testing machine. It’d be fascinating to cycle one of your locks 10,000 or even 50,000 times and see how it holds up. Could make for a great hands-on project—and some interesting data.
Wow, that is a fantastic offer and I'm sure a lot could be learned from it! Lets talk more...
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Bill my buddy!!! I’d never guessed you would come to my defense!
Jim, I think our issues are merely how we go about things. Many roads to Rome and I often just take the long way....With that said, your products are not sent out willy nilly. In fact I see you as a guy that is ever seeking to build a good product.
Are your frizzen springs forged/machined also, or are they cast?....Do you know how the old L&R springs are made?...are they casted?
Thank you, Bill. I think your right.
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Hi,
So getting back to Rich's initial post about differences among cast, forged and milled springs, I can strengthen, weaken, and reshape cast and forged springs to obtain any performance I require. Is there some reason I cannot do that with milled springs? My assumption is that I can alter a milled spring no differently than any other when clients request that I do so.
dave
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Like me or not that’s fine. The general belief today is that you shouldn’t question others, the customer is always right etc. I don’t subscribe to this. Truth or what I believe to be the truth is what guides me in these interactions.
One thing that we believe has helped us grow a thriving business is authenticity. Whether you can believe it or not, we are very kind, but we won’t be walked on and if you’re full of $#*& we’ll call you on it. These are principles we live by and won’t be changing soon even if it should mean fewer customers. Personally, I think this honesty, though admittedly coarse at times has helped us gain trust with our customers.
So it starts with criticism of the level of engraving, builder responds with specific examples and pics and then the comments are reduced to quality of work. That is about as unprofessional as it gets. It is like I have to win the argument so I resort to name calling. To bad this website does not have an ignore function. Sad that an adult sinks to that level.
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I'm sort of confused here... I don't think you understand the full story of what has gone on. The synopsis is I've been taking shots for some time. If you'll look at all my previous posts I never or hardly ever offer unsolicited criticism even it is screaming at me! I really do try to be kind and nice online and in my daily life, but when someone starts firing shots my way, I'll take them for a bit, but at some point the gloves will come off. Things can go both ways.
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Hi,
So getting back to Rich's initial post about differences among cast, forged and milled springs, I can strengthen, weaken, and reshape cast and forged springs to obtain any performance I require. Is there some reason I cannot do that with milled springs? My assumption is that I can alter a milled spring no differently than any other when clients request that I do so.
dave
Heck yes, a fellow can modify any spring regardless of how it's made to smaller dimensions and change it's strength.
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I work with cast springs often, about 90% percent of my work is done with casted springs from 6150 steel. The quality of the lost wax casting and the foundry’s pour are what make the difference in a cast springs quality. Positioning the spring is critical on locks for maximum energy, if a spring is placed too far or too low by a few MM, can be the difference between a great sparking lock and a mediocre sparking lock. When initially getting started on a lock the first i look over is the spring for kinks, cracks, voids and extra waxed over areas that indicate a correction by the caster (if the original was bent or broken).
CNC machined springs i have found to be heavy at times (not talking about Kibler springs here) because the machining processes used for often doesn’t capture complex designs or at least the techniques used by the designer didn’t consider it, the cutting process used for springs may also be flawed. Machined springs that are sold as ‘tempered’ and ready to drop in often are too hard. Machinist and metallurgist have suggested to me the machining processes used could be work hardening the product from overheating, poor cutters and or the burning of cutting fluid can sometimes carburize areas or of course improper programming can lead to a poor design. Over the years I’ve seen some great ones and some really rough looking ones that were nearly impossible to lighten without removing 30% of the lower leg, these made better use as paper weights than lock springs. Can a CNC spring be superior to cast, of course, it depends on the facts and circumstances of everything else and on any given day a cast spring could be superior to a CNC spring.
The original lock makers designed their springs after long periods of tedious failures and successes in forging springs, imagine how many must have been tossed aside. With casted springs, i do feel we are copying their best designs if the caster has chosen wisely. CNC springs that utilize programming often attempt to correct perceived flaws because well, we often imagine ourselves to be smarter than our predecessors i suppose, so its done.
Forged springs if done carefully and correctly are superior to both Cast and CNC springs, I’m not a metallurgist here just stating what iv’e noticed on my bench. Forged springs crafting techniques are extremely important, getting appropriate shapes and bends are critical or the entire part can be easily ruined with a wonky bend. One of the best springs i have in my shoppe is an original long land mainspring, complete with its elbow bending mark in all, the design of it, the tapering and width of the parts produced a spring that still works from its original temper 270 - 300 years ago with lower quality spring steel. Forged springs made in a die in my opinion are of the best, a lot reasons why, i believe its because of high load compression, temperature resistance during the forging process, and precision in the shaping of the legs, with a slightly oversized die made spring, one can file it in lesser critical areas to lighten it, i was able to accomplish this with a smith who was making rifle locks springs and musket sized springs from a die. A great example of die made springs were by Miroku, these were often very heavy left in a raw unshaped state, important to note that miroku made forged springs and casted ones too, they chose the method best suited for the project.
At the end of the day if the builder knows their craft, they’ll make a high quality product. But if i had my choice and the resources I’d have my springs forged in a die.
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Can you please show me where a 20ish yr old apprentice gun builder took a shot at you and deserves to be told her work is not up to your standards. Can you show me where LR took a shot at you and you trash their quality please.
Maybe you can clear up my confusion for I am a lefty and do not understand.
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Can you please show me where a 20ish yr old apprentice gun builder took a shot at you and deserves to be told her work is not up to your standards. Can you show me where LR took a shot at you and you trash their quality please.
Maybe you can clear up my confusion for I am a lefty and do not understand.
This engraving wasn't done by a 20 year old apprentice. I was taking issue how it was announce to be a certain quality. I think this is an insult to original English engravers, their work and those who understand and appreciate their work.
As far as L&R, even the best of us criticizes their work from time to time. From one perspective this is a public service announcement the the newcomers.
If you'd like to chat more about this, feel free to send me a PM. I'm happy to talk.
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FlinterNick,
Back to the point...
I feel pretty strongly you could make a spring by any of the three methods discussed to the same dimensions and feel no discernable difference in the lock.
From a materials standpoint it isn't too complicated. What we feel in a spring is the elastic nature. Metal such as a spring can be stretched or deformed a certain amount and then return to it's original state. The amount of force required for a given amount of deflection in a given size piece of material is the modulus of elasticity. This is the key measure. If I recall from a long time ago, I looked it up and found this to vary a tiny amount on castings relative to wrought material. It was so small that it was insignificant, though. Really, from a metallurgical or materials standpoint this is the only measure that matters with a spring in terms of how it feels in a lock. Seriously it's that simple...
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After a few thousand cycles without issue, my main spring broke while bringing the lock to full cock in preparation toffee at one of the biggest bucks I've seen in my life.
The spring was cast, and although it functioned perfectly for years, the breakage revealed a tiny air bubble in the casting. I now carry a spare spring in my bag, but that failure has stuck with me, and I will take one of Mr Kibler's machined springs or a forged spring over a cast spring any day if I have a choice . There is far less chance of a catastrophic failure IMO [ I can still see that buck ! ]
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(https://i.ibb.co/pjCQJS51/IMG-5458.jpg) (https://imgbb.com/)
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I work with cast springs often, about 90% percent of my work is done with casted springs from 6150 steel. The quality of the lost wax casting and the foundry’s pour are what make the difference in a cast springs quality. Positioning the spring is critical on locks for maximum energy, if a spring is placed too far or too low by a few MM, can be the difference between a great sparking lock and a mediocre sparking lock. When initially getting started on a lock the first i look over is the spring for kinks, cracks, voids and extra waxed over areas that indicate a correction by the caster (if the original was bent or broken).
inferior. CNC machined springs i have found to be heavy at times (not talking about Kibler springs here) because the machining processes used for often doesn’t capture complex designs or at least the techniques used by the designer didn’t consider it, the cutting process used for springs may also be flawed. Machined springs that are sold as ‘tempered’ and ready to drop in often are too hard. Machinist and metallurgist have suggested to me the machining processes used could be work hardening the product from overheating, poor cutters and or the burning of cutting fluid can sometimes carburize areas or of course improper programming can lead to a poor design. Over the years I’ve seen some great ones and some really rough looking ones that were nearly impossible to lighten without removing 30% of the lower leg, these made better use as paper weights than lock springs. Can a CNC spring be superior to cast, of course, it depends on the facts and circumstances of everything else and on any given day a cast spring could be superior to a CNC spring.
The original lock makers designed their springs after long periods of tedious failures and successes in forging springs, imagine how many must have been tossed aside. With casted springs, i do feel we are copying their best designs if the caster has chosen wisely. CNC springs that utilize programming often attempt to correct perceived flaws because well, we often imagine ourselves to be smarter than our predecessors i suppose, so its done.
Forged springs if done carefully and correctly are superior to both Cast and CNC springs, I’m not a metallurgist here just stating what iv’e noticed on my bench. Forged springs crafting techniques are extremely important, getting appropriate shapes and bends are critical or the entire part can be easily ruined with a wonky bend. One of the best springs i have in my shoppe is an original long land mainspring, complete with its elbow bending mark in all, the design of it, the tapering and width of the parts produced a spring that still works from its original temper 270 - 300 years ago with lower quality spring steel. Forged springs made in a die in my opinion are of the best, a lot reasons why, i believe its because of high load compression, temperature resistance during the forging process, and precision in the shaping of the legs, with a slightly oversized die made spring, one can file it in lesser critical areas to lighten it, i was able to accomplish this with a smith who was making rifle locks springs and musket sized springs from a die. A great example of die made springs were by Miroku, these were often very heavy left in a raw unshaped state, important to note that miroku made forged springs and casted ones too, they chose the method best suited for the project.
At the end of the day if the builder knows their craft, they’ll make a high quality product. But if i had my choice and the resources I’d have my springs forged in a die.
Flinter Nick,
I couldn't have said that any better. Your observations have been similar to mine. And your conclusions too.
In my own shop while working to bring the Ditchburn Beck lock back to market i designed many dies and tried many different orders of operation. Still a economicly viable forged spring has evaded me.
I do have a cnc mill and am more than capable of milling the mainspring. In fact I fully intend to mill my frizzen springs when my cast ones run out. Anyhow, milling the mainsprings would be a very easy fix for my predicament. Vey easy! So why aren't I doing it? So glad you asked: )
I know i wouldn't be able to improve on a well made forged spring. And I also have seen enough issues with milled springs that I am not willing to chase that endeavor when perfectly reliable cast springs are readily available.
Maybe someday when I have time to invest I'll revisit milled mainsprings. But my experience has shown me that I don't want or need to tackle this monkey here and now. I know of many "light spring " failures that have been fixed by gunsmith friends of mine. Smartdog has pointed out his customers wanting something lighter.
So until I have a lot of time to invest in making sure it is "right" I am going to use a spring with a 60 year track record.
That is my thought process. I am not married to any particular process and may or may not change in the future. I never say never because I am not the smartest guy in the room. I am always learning. And want to continue to learn. Technology is always evolving and my goal is to get the best product i can at an affordable price to the people who want it!
Best
CE
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(https://i.ibb.co/pjCQJS51/IMG-5458.jpg) (https://imgbb.com/)
Great you brought this up. I touched on it earlier in my rants, but it could easily get lost. As a metallurgist working in a forging plant I routinely did grain flow analysis on parts we made. The classic example is a lifting hook. You want the grain to flow around the shape.
With a bent spring you have grain flow following around the shape of the part. With a cast spring you have a completely random grain pattern. With a spring machined from a billet the grain flow is parallel and generally follows the legs of the spring but has a cross grain orientation at the bend.
This cross grain isn't ones first choice in designing a part, but you have to ask yourself if it is significant. Mechanical properties are slightly different along the grain versus across the grain. I could look all of them up (tensile strength, impact strength, fatigue life etc.) but I don't have the exact numbers right now. My recollection was that all of the cross grain properties were in the range of at least 80%-90% of the properties parallel to the grain.
So, is this a concern? Do you need to do anything? Well it depends... It depends on the stress level at this cross grain location. Software allows FEA analysis to determine stress along a part like this when it's put into load. As I recall, even with the spring cross section a normal thickness, exceeding these diminished mechanical properties wasn't much of a concern. But, as an added safety measure, all one has to do is make the cross section at the bend a little bigger! Bigger cross section lowers the stress and negates any concerns with grain orientation.
Simple as this!
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A little back story on machined springs. As far as I know I'm the only one doing this. If anyone else is, it would be interesting to hear. When I decided to make locks I contemplated the different methods of manufacture and machining seemed like the best choice. I wasn't aware of this being done before. I went to the CLA show the year I was developing my locks and was discussing them with Jud Brennan. For those who don't know, he is at the top of the heap of longrifle builders. Anyways... I told him how I was making springs and he said he makes them the same way with a bandsaw, mill and files. Jud can forge out anything he wants, but said he just finds it way easier to work from the solid removing material than forging and that they work great! Anyone that knows Jud and all the wonderful high end locks he's built over the years will recognize this as a testament.
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And another story... When we first started making locks and springs there was a learning curve. We failed on the first batch that went out in that the springs were tempered too soft. To start with they were a little on the weak side and then over time the even lost more of their set. Well, we're all a group in the muzzleloading world and although everyone generally gets along, it's always appealing to be able to criticize the new guy, especially one outspoken like myself.
So... a fast talking lock maker who's words are in my opinion more impressive than his work got hold of this and the word spread about how these machined springs are prone to "taking a set". In reality it had nothing to do with the way they were made, but rather the fact that they were just too soft. Those that didn't really care for what I was doing latched hold of this and perpetuated this rumor. I believe this is why to this day, I sometimes still hear this.
Needless to say, we quickly corrected the soft spring issue and it's all been downhill on springs since. It really is simple... if you can machine it to shape, and heat treat it properly, there are no problems to solve.
Well over 10k in the field and no breaks. This is especially significant given the strength of our springs and how hard we push them.
A recent report of on with over 10k cycles. Let's just say I'm not worried...
There are certainly other methods of making a spring that work fine, but so does this.
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(https://i.ibb.co/pjCQJS51/IMG-5458.jpg) (https://imgbb.com/)
Great you brought this up. I touched on it earlier in my rants, but it could easily get lost. As a metallurgist working in a forging plant I routinely did grain flow analysis on parts we made. The classic example is a lifting hook. You want the grain to flow around the shape.
With a bent spring you have grain flow following around the shape of the part. With a cast spring you have a completely random grain pattern. With a spring machined from a billet the grain flow is parallel and generally follows the legs of the spring but has a cross grain orientation at the bend.
This cross grain isn't ones first choice in designing a part, but you have to ask yourself if it is significant. Mechanical properties are slightly different along the grain versus across the grain. I could look all of them up (tensile strength, impact strength, fatigue life etc.) but I don't have the exact numbers right now. My recollection was that all of the cross grain properties were in the range of at least 80%-90% of the properties parallel to the grain.
So, is this a concern? Do you need to do anything? Well it depends... It depends on the stress level at this cross grain location. Software allows FEA analysis to determine stress along a part like this when it's put into load. As I recall, even with the spring cross section a normal thickness, exceeding these diminished mechanical properties wasn't much of a concern. But, as an added safety measure, all one has to do is make the cross section at the bend a little bigger! Bigger cross section lowers the stress and negates any concerns with grain orientation.
Simple as this!
What about the work hardening, strain, that occurs during the cutting process that can affect the quality? In my experiences this not something that can just be drawn out with tempering. These deformations can often be permanent. The straight grain pattern now becomes skewed / strained.
Will it work .. sure, you might need to do some dumbbell curls or use two hands to cock it to make it work, and find the best flints and that may be ok for some people and it may not.
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Once you heat to above the recrystalization temperature, any stress in the material, grain deformation etc is erased and new grains are formed. This is around 1200 F or so.
If you're interested look up "recover, recrystalization and grain growth" in steel.
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Once you heat to above the recrystalization temperature, any stress in the material, grain deformation etc is erased and new grains are formed. This is around 1200 F or so.
If you're interested look up "recover, recrystalization and grain growth" in steel.
Make them harder you’re saying will correct machine work hardening grain structures? That only holds true for CNC springs? Not casted springs with random grain patterns?
I understand there’s research regarding this phenomenon and how to correct it, however it’s not considering springs … I see it for tools and non elastic parts. Either way my opinion of machined made springs is they’re consistently overly strong and heavy.
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No, all I'm saying is that any machining induced stress etc. is eliminated during the post machine heat treatment (harden and temper).
You can heat treat a machined spring to any hardness you like just the same as a cast or forged one. They'll act the same if they have the same geometry.
The only caveat is that the modulus of elasticity of cast steel is just slightly lower on a steel casting than wrought material. It's so small, I don't think anyone would feel the difference. I would wager LOTS of money that if I made three springs, one forged, one machined from billet and one cast with identical geometry a person wouldn't be able to pick out the which was which in a statistical trial.
Also, hardness in no way determines the stiffness or strength of a spring provided you don't stress it beyond the elastic limit. Or in other words, as long as the spring doesn't take a set, you could have one at 35 HRC and the other at 50 HRC and the strength to pull the cock back would be the same.
What determines a steel springs strength is geometry and a minimum hardness such that you don't exceed the yield point (spring taking set).
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I'm not a metallurgist, but here's what I gather:
- Cast springs are considered “fair-good.”
- Milled springs are “better.”
- Forged springs are “best.”
However, the difference between milled and forged springs is often negligible in many cases.
These theoretical discussions are fascinating. Would it be more effective to mill a spring flat and then bend it, or to mill it into shape directly?
If I’m understanding correctly, milling it flat and then bending it might align the grain structure but could also introduce some internal tension. This tension could be alleviated through reheating or tempering, allowing for grain recrystallization.
That said, if a lock functions properly, does it even matter? This topic keeps resurfacing—beating a dead horse at this point.
I think lock function and durability as a single unit is a better use for study. A tuned lock vs untuned makes the world of difference.
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When machined by a semi-competent person the depth of the work hardening due to machining in typical steels is nearly zero, this is also the depth of any grain change that might take place. I say nearly zero because you cannot see it without very specialized tools. It just isn't an issue. If it is machined by Mongo and is burnt and blued when it comes out of the machine you may have an issue, but if we go back to the semi-competent using halfway decent tools and a bit of coolant in the cut you won't see a material change that is even a couple thousandths of an inch deep. If machined well by competent people with good tools and cutting conditions the depth of measurable material change will be parts of 1 thousandth of an inch. And this is all assuming that we would machine from pre-hardened material and only temper. If we machine soft, heat treat fully with a quench and temper any changes from the machining are mitigated completely. In very high temperature alloys (high nickel primarily) you can see the depth of change reach from machining in the .003-.005" range. Even if we made gun parts out of inconel and could hold small parts well enough to really push cuts hard this would be a very small percentage of the overall material involved.
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I don’t think there is any noticeable difference in the function of any of the three.
Cast springs most likely have a higher chance of breakage due to the increase chance of defects from the casting process.
A properly forged spring with grain flow wrapping around the bend would in theory be the best of the manufacturing methods, but it’s increased strength, fatigue resistance might not be significant given the spring dimensions etc. sort of like hardened 4140 steel for a barrel is stronger than 8620, but is hardened 4140 necessary?
And there is another caveat, the bending and forming process can introduce defects unless very carefully done, this increasies the chance of failure relative to machined billet.
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I am not a metallurgist.
But from what i understand that
Cast springs are “good”
Milled Springs are “Better”
And forged Springs are “Best”
However, the difference between Milled and Forged is probably not noticeable/ negligible in most instances.
Cast springs are fine, they’re all fine but forged springs get my vote for all the reasons Jim mentioned and I trust that original gunmakers knew their craft better than we do. Ironically they began casting springs around 1850 once they started adding manganese. It’s what is demanded of your lock that’s the difference. I’ve made hundreds of locks with cast springs generate more than acceptable ignition.
The real difference is who’s making them, designing them and of course their fee and how much someone is willing to pay.
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First of all.I DO NOT burn off oil and call it done.After washing oil OFF with alcohol or Varsol if I have any I then polish the hardened preshaped spring and use a Bernzomatitic torch to temper by watching the color change and dwell time at the bend.So far no problems.
.Very high success rate and no reason to change.
Bob Roller
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First of all.I DO NOT burn off oil and call it done.After washing oil OFF with alcohol or Varsol if I have any I then polish the hardened preshaped spring and use a Bernzomatitic torch to temper by watching the color change and dwell time at the bend.So far no problems.
.Very high success rate and no reason to change.
Bob Roller
Thanks for clarifying, Bob.
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I don't know if I clarified anything or not but 50+years of experience must count for something.The only thing really important to me was getting the right material and then a technique to bring it to a successful conclusion and that helps in a big way to be worry free about breakage and that is because of the uniform quality of 1075.I still have enough to last longer than I will.I learned spring making from George Killen beginning at age 15 and he allowed me to watch him.His heat source was a big gasoline blow torch he modified with a tire valve so he could pressurize it with a tire pump.I was a willing student and wanted to know about making springs and anything else.Another one was Bill Large who taught me about machine tools and a myriad of other things.
This started in 1953 and that lasted until Bill passed away in 1985. Later I convinced one of Bill's daughters to sell Bill's shop to Jim McLemore so he could expand his shop.This has nothing to do with making springs but are part of my life experiences in a variety of venues.
Bob Roller
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After a few thousand cycles without issue, my main spring broke while bringing the lock to full cock in preparation toffee at one of the biggest bucks I've seen in my life.
The spring was cast, and although it functioned perfectly for years, the breakage revealed a tiny air bubble in the casting. I now carry a spare spring in my bag, but that failure has stuck with me, and I will take one of Mr Kibler's machined springs or a forged spring over a cast spring any day if I have a choice . There is far less chance of a catastrophic failure IMO [ I can still see that buck ! ]
I had called up two gobblers, got in front of them by wading and was hidden in the roots of a large, old oak. When they came out of the palmettos the first one was the biggest gobbler I have ever seen. He was in my sights when I cocked my rifle. And the mainspring broke......
First time that had happened and I was without a spare. No choice but to go home 65 miles away. Now I always carry a spare.
Before I retired I was a SME (subject matter expert) for the Air Force on several processes, one was the manufacture of hard critical airframe components, so I have some indepth knowledge on this subject. Based on nearly 40 years experience this is what I think....
If given the choice my mainspring would be machined from a forging. For me, that says it all.
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I'm not a metallurgist, but here's what I gather:
- Cast springs are considered “fair-good.”
- Milled springs are “better.”
- Forged springs are “best.”
However, the difference between milled and forged springs is often negligible in many cases.
These theoretical discussions are fascinating. Would it be more effective to mill a spring flat and then bend it, or to mill it into shape directly?
If I’m understanding correctly, milling it flat and then bending it might align the grain structure but could also introduce some internal tension. This tension could be alleviated through reheating or tempering, allowing for grain recrystallization.
That said, if a lock functions properly, does it even matter? This topic keeps resurfacing—beating a dead horse at this point.
I think lock function and durability as a single unit is a better use for study. A tuned lock vs untuned makes the world of difference.
John, milling in a flat state and then adding the bend was one method I was working with. It was taking me too many heats to get to the end result. There was a fellow who made locks back in the 70's who could get the whole thing done in two heats. I know it is possible so I may revisit this one day. Repetition breeds familiarity and I bet after a few hundred, certainly several thousand, the process would become imminently more efficient.
CE
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After a few thousand cycles without issue, my main spring broke while bringing the lock to full cock in preparation toffee at one of the biggest bucks I've seen in my life.
The spring was cast, and although it functioned perfectly for years, the breakage revealed a tiny air bubble in the casting. I now carry a spare spring in my bag, but that failure has stuck with me, and I will take one of Mr Kibler's machined springs or a forged spring over a cast spring any day if I have a choice . There is far less chance of a catastrophic failure IMO [ I can still see that buck ! ]
I had called up two gobblers, got in front of them by wading and was hidden in the roots of a large, old oak. When they came out of the palmettos the first one was the biggest gobbler I have ever seen. He was in my sights when I cocked my rifle. And the mainspring broke......
First time that had happened and I was without a spare. No choice but to go home 65 miles away. Now I always carry a spare.
Before I retired I was a SME (subject matter expert) for the Air Force on several processes, one was the manufacture of hard critical airframe components, so I have some indepth knowledge on this subject. Based on nearly 40 years experience this is what I think....
If given the choice my mainspring would be machined from a forging. For me, that says it all.
A machined forging would be the nads. If I had a drop hammer this would become my goal
I nearly bought one last year from a closed machine shop up in Philly. The roof had caved in and getting that beast out was more than I wanted to fool with. But someday....!
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Is that not the way they did it on the old days, blacksmithing then white smithing?
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It was taking me too many heats to get to the end result. There was a fellow who made locks back in the 70's who could get the whole thing done in two heats. I know it is possible so I may revisit this one day.
I was a smiths apprentice as my very first career and we had a saying that a good smith could forge a locomotive in one heat.
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I'm no lock expert. Nor do I have decades of lock or metalurgy experience. But I do have observations.
Several months back I was tuning a lock (New old stock Dixie flint) and during that process, I took my small group of flintlock firearms and measured the poundage required to pull the cock from rest, to full cock. Here's the poundage as measured by a Lyman Digital trigger pull gauge: Rifle L&R 9.1, Rifle L&R 9.5, 50 Cal Pistol Chambers Queen Ann 7.15, 45 Cal Pistol-Dixie 10.1.
Now, all of these locks provide very good ignition and they all provide great flint life. A lock that would give me 4 or 5 shots before requiring a flint replacement would either be tuned or sent down the road.
It also seems to me that any lock with a pull greater than 15-lbs would give me pause as to why. If the answer is an almost imperceptible speed increase in lock time at the sacrifice of a new flint every 5 shots, I'd prefer adequate lock speed with longer flint life.
But, that's me.
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I really don't know what the force is to cock our locks. I don't measure it as I can feel what is a good weight and what isn't. After all this hub-bub, just this morning I took about a dozen of our locks and checked each one for function. They all felt really good. Springs not too strong nor too weak. I snapped each one a handful of times and no issues. I snapped one at least 40 times and no issues with a flint. This is how our locks generally work. I see absolutely no reason to change a thing. The spring weight is perfect in my view.
I can honestly say, our locks are the gold standard of what is available today. We're very proud of what we've accomplished with these.
Here's an interesting thing about locks.... I recall years ago, Jim Chambers making a comment here about customer preferences. In short he said the problem that one person might like weak springs and the next might like them really strong. Each thinks they're absolutely right as well, so it goes to show you can't please everyone no matter what you do. This was when he was working with his Ketland lock spring weight.
I'll also say that I believe flint breakage is sometimes due to the initial strike against the frizzen, but I think frizzen bounce back is more of an issue than we sometimes realize. I'd like to dig into this more.
I'm also going to take 44 Henry up on his offer of building a test rig to cycle locks. This should be interesting...
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Also, does anyone have access or know of any way to get our hands on a very high speed camera. No the level of a cell phone, but the serious ones. I looked a while ago and saw they were very expensive; tens of thousands or even a hundred thousand. I can't justify this, but do recognize one would be fantastic in evaluating a lock. Not only for timing but also for examination of function in detail. I recall seeing the Brown Bess show on PBS a while ago and they used something like this. It was revealing for sure.
Thanks!
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Jim, you can rent high speed cameras. https://www.renthighspeed.com/ I haven't used these guys but the site looks good. The last time I rented cameras I had to rent the crew with them and it was a couple grand a day to troubleshoot some high speed automation glitches. Well worth it in my case but silly expensive for the subject of this thread IMO.
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Jim,
You might try contacting Larry Pletcher. He is a member here and has done high speed videos and lock timing in the past. https://www.blackpowdermag.com/category/videos/ Scroll down for videos.
Ron
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Professional high-speed cameras typically start around $3,000 and go up from there. That said, some of my students have mentioned hacks using Raspberry Pi setups and other systems that can replicate much of this functionality for just a few hundred dollars. Granted it sounds like they would all still be under 1000 frames per second which is low, but could still be useful for testing a lock. While perhaps not on par with professional systems in terms of high-end performance, I’ve learned that engineering students tend to get pretty creative when it comes to avoiding major expenses—probably so they have more money left over for beer.
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Here's a video I took of a Manton lock that was giving me fits as to why my frizzen was not opening fully. Well, you can see the frizzen was opening fully....and because of a weak frizzen spring it was snapping back to the flint.
BTW....taken with an iPhone 16 Pro with the video set in slow motion.
Not a high speed by any means and for a very detailed lock testing of hundreds if not thousands of cycles this may not "cut it".....but if nothing else it could provide some data.
FWIW
https://i.imgur.com/vfdDri8.mp4
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I really don't know what the force is to cock our locks. I don't measure it as I can feel what is a good weight and what isn't. After all this hub-bub, just this morning I took about a dozen of our locks and checked each one for function. They all felt really good. Springs not too strong nor too weak. I snapped each one a handful of times and no issues. I snapped one at least 40 times and no issues with a flint. This is how our locks generally work. I see absolutely no reason to change a thing. The spring weight is perfect in my view.
I can honestly say, our locks are the gold standard of what is available today. We're very proud of what we've accomplished with these.
Here's an interesting thing about locks.... I recall years ago, Jim Chambers making a comment here about customer preferences. In short he said the problem that one person might like weak springs and the next might like them really strong. Each thinks they're absolutely right as well, so it goes to show you can't please everyone no matter what you do. This was when he was working with his Ketland lock spring weight.
I'll also say that I believe flint breakage is sometimes due to the initial strike against the frizzen, but I think frizzen bounce back is more of an issue than we sometimes realize. I'd like to dig into this more.
I'm also going to take 44 Henry up on his offer of building a test rig to cycle locks. This should be interesting...
I use a spring tester / force gauge. The go pro cameras work in all speeds.
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Jim,
You might try contacting Larry Pletcher. He is a member here and has done high speed videos and lock timing in the past. https://www.blackpowdermag.com/category/videos/ Scroll down for videos.
Ron
Thanks. I've worked with Larry in the past and he graciously did some timing tests on our Ketland lock. He uses a very old set-up that basically trips the sear, starts a timer at this point and then uses a photo cell that trips at a certain intensity of light from the priming powder. The time between these events is what he measures and reports as the lock time. Anyways, I was just considering with improved cameras today, you might be just able to measure lock time from the camera recording in some way. It would also be neat to very carefully watch the flint and frizzen interaction along with potential bounce-back etc.
Jim
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I really don't know what the force is to cock our locks. I don't measure it as I can feel what is a good weight and what isn't. After all this hub-bub, just this morning I took about a dozen of our locks and checked each one for function. They all felt really good. Springs not too strong nor too weak. I snapped each one a handful of times and no issues. I snapped one at least 40 times and no issues with a flint. This is how our locks generally work. I see absolutely no reason to change a thing. The spring weight is perfect in my view.
I can honestly say, our locks are the gold standard of what is available today. We're very proud of what we've accomplished with these.
Here's an interesting thing about locks.... I recall years ago, Jim Chambers making a comment here about customer preferences. In short he said the problem that one person might like weak springs and the next might like them really strong. Each thinks they're absolutely right as well, so it goes to show you can't please everyone no matter what you do. This was when he was working with his Ketland lock spring weight.
I'll also say that I believe flint breakage is sometimes due to the initial strike against the frizzen, but I think frizzen bounce back is more of an issue than we sometimes realize. I'd like to dig into this more.
I'm also going to take 44 Henry up on his offer of building a test rig to cycle locks. This should be interesting...
I use a spring tester / force gauge. The go pro cameras work in all speeds.
The cameras I'm referring to are extremely high speed cameras. We've used go pro, cell phones etc. They don't slow things down enough for our purposes. I'm with you on the force guages.
Follow the link that HsmithTX posted above to see what I'm talking about.
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Professional high-speed cameras typically start around $3,000 and go up from there. That said, some of my students have mentioned hacks using Raspberry Pi setups and other systems that can replicate much of this functionality for just a few hundred dollars. Granted it sounds like they would all still be under 1000 frames per second which is low, but could still be useful for testing a lock. While perhaps not on par with professional systems in terms of high-end performance, I’ve learned that engineering students tend to get pretty creative when it comes to avoiding major expenses—probably so they have more money left over for beer.
Great information once again! Thanks so much.
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Thanks. I've worked with Larry in the past and he graciously did some timing tests on our Ketland lock. He uses a very old set-up that basically trips the sear, starts a timer at this point and then uses a photo cell that trips at a certain intensity of light from the priming powder. The time between these events is what he measures and reports as the lock time. Anyways, I was just considering with improved cameras today, you might be just able to measure lock time from the camera recording in some way. It would also be neat to very carefully watch the flint and frizzen interaction along with potential bounce-back etc.
Jim
Larry had access to a high speed camera for a while and made a series of videos that showed flint and frizzen interaction. I used to help him once in a while and he burned me a CD showing the locks he was doing at the time. I've probably still got it laying around somewhere. If I recall, most of the locks had frizzen bounce back.
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The frizzen bounce back (FWIW) I discovered by accident. I could stare at that lock every time and the bounce back occurred so quickly, the human eye cannot see it. (Well...I think I'm human....just don't ask the Mrs).
So, at one point I was holding the rifle with my left had where my left thumb nail was (unbeknownst to me) in the direct line of when the frizzen snapped open. So, when I pulled the trigger the frizzen "WHACKED" my thumbnail!! And I still couldn't see it happen!! I did this a few more times (with thumbnail protected) and that's how I found the problem.
In addition, the bounce back usually won't occur if you're holding the lock in your hand (as opposed to the lock being in the stock). Your hand (well...my hand) would absorb enough of the energy that the frizzen would stay open. This gave me the "false" thinking that there was something in the stock that was impinging the lock movement....and me thinking not enough force was hitting the frizzen.
Very scientific method. It's called "whack your nail and withdraw in pain." That's the scientific term....honest....google it. ;)
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I only use Chambers large siler LH locks because I'm lefthanded and I'm very familiar with these locks. When I tune a lock a priority is to get any jar out of the rifle when shot. I've tracked this to a heavy frizzen spring. Lots of testing has shown there is a fine line between no jar and bounceback.
I measure with a trigger gauge hooked to the top of the frizzen. My goal is to get as close to 4 pounds as possible. Testing has shown this weight removes all jar and creates no bounceback. I use a dremel to reduce the spring. I measure the spring thickness to control where I'm at. Starting with a coarse drum I transition to a fine drum. The last thing I do is polish any tool marks from the spring to help prevent a crack from starting.
I never reduce a main spring. Doing so will reduce the spring strength and slow the lock. Though I have polished the surface of a few.
I never weigh a main spring either. Like Jim I can tell if the spring is of a weight that works for me just by cocking it a few times.
I feel that too many shooters want to blame the mainspring for a variety of problems when in fact something else is the culprit.
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It was taking me too many heats to get to the end result. There was a fellow who made locks back in the 70's who could get the whole thing done in two heats. I know it is possible so I may revisit this one day.
I was a smiths apprentice as my very first career and we had a saying that a good smith could forge a locomotive in one heat.
Was that a B&O yard engine or a Union Pacific "Big Boy" ;D? I have bent/forged lock mainsprings in 2 heats and used an acetylene torch,
1075 is a forgiving material for any lock springs and I have them all over the world and my methods rank with the stone axe.
Bob Roller
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I have an L&R Durrs Egg flintlock that’s about 46 years old. It went through two broken cast main springs.
They refitted the lock to accommodate their new Durrs Egg forged (or machined?) mainspring.
I think the new one will last longer, though in 46 more years I don’t think I will be pulling too many triggers to know. 🤣
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I'm not a lock maker, but what does that mean when they say " a machined spring taking a set" ? or other versions of a mainspring taking a set. A set of what? Lock parts?
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"Taking a set" refers to when a spring is compressed, and doesn't return to its original "wanted" or "full spring" position. Thus it will be weakened permanently from the original intended power.
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Weakened permanently until it is heated, restored to original dimension and re heat treated to a more appropriate temper.
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Any spring can take a set. The way that it is made has minimal bearing upon the issue, although possibly true metallurgists might argue that point. I will say that there are a LOT of antique locks with forged springs (both main and frizzen) that have weakened over time and 'taken a set.' Frankly, I've seen barely any of it in modern cast springs, assuming they were tempered properly. They tend to simply snap like a cracker while many old forged springs may crack but continue to function. Is it an age issue? I don't know but I would say that many modern shooters are shooting and thus cycling locks much more frequently than a gun owner 200+ years ago likely did. Individual shooting for fun is a lot more prevalent now than historically, I suspect.
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Any spring can take a set. The way that it is made has minimal bearing upon the issue, although possibly true metallurgists might argue that point. I will say that there are a LOT of antique locks with forged springs (both main and frizzen) that have weakened over time and 'taken a set.' Frankly, I've seen barely any of it in modern cast springs, assuming they were tempered properly. They tend to simply snap like a cracker while many old forged springs may crack but continue to function. Is it an age issue? I don't know but I would say that many modern shooters are shooting and thus cycling locks much more frequently than a gun owner 200+ years ago likely did. Individual shooting for fun is a lot more prevalent now than historically, I suspect.
Depends on what they’re casted in. 1080 or 1095 cast springs are tricky same with 5160 cast springs, although you dont see them too often. They have to be tempered correctly or they will eventually shatter sitting in the lock.
I only use 6150 for my castings and ones I’ve purchased, i also use 6150 in billet for forgin, I’ve never broken one. The manganese content enables flexibity of the steel.
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Though not in the business, I’ve heard tales of foundries using steel that was not specified when filling small orders of list wax casting. I suppose that could lead to some issues with cast springs that would not typically happen with forged or machined springs.
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"Taking a set" refers to when a spring is compressed, and doesn't return to its original "wanted" or "full spring" position. Thus it will be weakened permanently from the original intended power.
Thanks for that explanation! It all makes sense now what you're talking about.
when I think about what you guys are saying especially along with Eric Kettenburg's explanation as well, I think of the time that I had looked into some old CVA locks that some guys bring into the shop, their mainspring was working just fine, but the sear spring was just like you described, and also on some other locks the frizzen springs were also in the same condition, just too weak to come back to where it was.
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Though not in the business, I’ve heard tales of foundries using steel that was not specified when filling small orders of list wax casting. I suppose that could lead to some issues with cast springs that would not typically happen with forged or machined springs.
That’s certainly happened before with the rifle shoppe, sometimes they accidentally pour 4140 steel for the springs. One way to tell is to take a bluing pen and mark the spring, if it turns violet then it’s likely 4140.
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Any spring can take a set. The way that it is made has minimal bearing upon the issue, although possibly true metallurgists might argue that point. I will say that there are a LOT of antique locks with forged springs (both main and frizzen) that have weakened over time and 'taken a set.' Frankly, I've seen barely any of it in modern cast springs, assuming they were tempered properly. They tend to simply snap like a cracker while many old forged springs may crack but continue to function. Is it an age issue? I don't know but I would say that many modern shooters are shooting and thus cycling locks much more frequently than a gun owner 200+ years ago likely did. Individual shooting for fun is a lot more prevalent now than historically, I suspect.
I see that often with springs that were not tempered correctly, usually they were tempered too high in a non controlled environment such as with a hand held torch and not a gauged device or oven. Torch tempering can be difficult, catching that second blue is critical, and iit happens quickly. John Bosh was color blind and relied on the slight color of red in complete darkness to get his springs tempered in complete darkness a slight red color is generally around 750-800, by slight i mean hardly noticeable to someone who is not color blind.
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John Bosh was color blind and relied on the slight color of red in complete darkness to get his springs tempered in complete darkness a slight red color is generally around 750-800, by slight i mean hardly noticeable to someone who is not color blind.
I do mine the same way. I know it sounds weird, but the 'slight red' is almost more "sensed" than actually seen. If it's too easy to see, you've generally gone too far.
Kit Ravenshear told me about that method probably 30 years ago and I think he may have mentioned it or discussed it further in one of those little booklets he authored, but I don't have them so I'm can't be positive.