Author Topic: Tuning locks  (Read 1222 times)

Online webradbury

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Tuning locks
« on: August 05, 2018, 07:12:48 PM »
What is the basic process for lock tuning? I want to learn
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Offline Jeff Durnell

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Re: Tuning locks
« Reply #1 on: August 05, 2018, 07:46:51 PM »
Good question. I'd like to learn about it as well.

Online PPatch

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Re: Tuning locks
« Reply #2 on: August 05, 2018, 07:47:46 PM »
The object is to make the lock as quick firing as it can be.

The basic technique is to polish all baring metal surfaces, those surfaces that touch one another. This is a matter of some fine file work done very lightly but to not alter the geometry of the parts, just to remove casting lines, spurs etc, and then switch to either stones or fine wet paper (a light oil or mineral oil) to complete the polishing to a high degree. Use some sort of transfer medium to check if any parts are rubbing against the lock plate, if so polish both surfaces. You will want to use sticks to wrap fine sandpapers on or load with polishing compound to get that final sheen.

Take your time, check often and go lightly at all times.

dave
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Offline Bob Roller

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Re: Tuning locks
« Reply #3 on: August 05, 2018, 08:24:35 PM »
The first thing to do is be sure the mainspring has enough strength to swing the cock
and make it spark.Is there a decent volume of sparks? If not,try to find out why.
Take the lock apart and see if there are any "rub" marks from the rotation of the tumbler
or other uneeded  contact on the underside of the bridle.Sometimes there will be contact
while assembling the lock and is really no problem.Sluggish performance from a flintlock
will instantly noticeable and if it's a new and never mounted lock it should be sent back to
the maker or whoever it was bought from.Strong,NOT STIFF mainsprings and close fitting
and aligned parts are the key to get a flintlock operating .Move the frizzen back and for the to check for "drag"
and friction as it crosses the spring and if it has a cammed spring (one with a ramp)to create
resistance to the downward swing of the flint and scrape of the flint. A frizzen with a roller or a
spring with a roller like the Late Ketlands should snap over and work easily when operated by hand.
Caplocks are not so critical but both flint and cap locks should have a first postion or half cock
that will absolutely hold against the power generated by the power of the mainspring and nothing more.
ANY LOCK WITH A HALF COCK NOTCH CAN BE DESTROYED by a hard pull on the trigger or an
aggressive set trigger.The old saying about "going off half cocked"originated with gun locks
so make sure this important feature is working.
Most new locks have a "fly"or what is really an intercepting cam that will allow the sear to slide
over the half cock with no effort and will swing back to allow to the first position or half cock.
I have no idea about parting lines other than to say I don't need them or use any cast internal
parts of any kind.

Bob Roller

 

 

Offline RAT

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Re: Tuning locks
« Reply #4 on: August 07, 2018, 04:56:19 AM »
In my experience makers cut far too many threads on lock screws. When you crank down the sear screw until it's tight, it often forces the bridal arm down against the sear and binds the lock. Loosening it just makes things sloppy and inefficient. You can always make a new sear screw with the correct length of thread and minimal clearance between the screw shaft and hole in the sear. I believe Chambers recommends .001". This eliminates slop when the trigger pushes up on the sear arm to trip the tumbler. This alone will improve trigger pull before you ever touch the sear nose and tumbler notches.
Bob

Offline Bob Roller

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Re: Tuning locks
« Reply #5 on: August 07, 2018, 04:29:33 PM »
In my experience makers cut far too many threads on lock screws. When you crank down the sear screw until it's tight, it often forces the bridal arm down against the sear and binds the lock. Loosening it just makes things sloppy and inefficient. You can always make a new sear screw with the correct length of thread and minimal clearance between the screw shaft and hole in the sear. I believe Chambers recommends .001". This eliminates slop when the trigger pushes up on the sear arm to trip the tumbler. This alone will improve trigger pull before you ever touch the sear nose and tumbler notches.

I make sure mine don't go in too deep and bind the sear is done by using (making)
a stub thread sear screw that bottoms out in the lock plate when tightened.The short
thread will put the smooth shank of the sear screw INTO the plate and help with the
back thrust of the mainspring at full cock.This is NOT a new idea and comes from the
famous English Gun Maker W.W.Greener and I think it's covered by an old patent.
Production is fine as far as it goes but it does have to give way to expedients at times.
I am not a major maker but do have more than a little experience with these little
mechanisms.One idea I am thinking of is a Carson style Hawken lock with an English
mechanism that uses the 3 screw bridle with the sear on an axle.I just finished a
4 screw Alex Henry style for a well known maker and I can see NO difference in the smooth
operation of the Henry lock and the 3 screw lock.I have made a number of these 3 screw
types for a German shop for schuetzen target rifles and some have been in use by serious
shooters for over 30 years.
Bob Roller
 

Offline Steve-In

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Re: Tuning locks
« Reply #6 on: August 07, 2018, 06:17:27 PM »
The Gunsmith of Grenville County has detailed instructions on tuning a lock.
I have not used them so I can't say how well they work.  Picked up my copy at a garage sale for $5.
All I have ever done is polish surfaces where they move against each other.
Steve Neher

Offline rich pierce

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Re: Tuning locks
« Reply #7 on: August 07, 2018, 08:09:32 PM »
I posted on polishing a lock and there may be some helpful things in there.
http://americanlongrifles.org/forum/index.php?topic=47002.0
St. Louis, Missouri

Offline Jim Kibler

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Re: Tuning locks
« Reply #8 on: August 07, 2018, 08:21:18 PM »
In order to "tune" a lock to the best possible state you really need to know what the ideal lock is.  This isn't something that can be described to concisely.  There's also a lot of opinions on what an ideal lock is.

Jim

Offline Darkhorse

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Re: Tuning locks
« Reply #9 on: August 07, 2018, 09:39:33 PM »
To start with I work the top of the pan until no, or very little light shines through when the friz is closed. Then I straighten and flatten the lock plate. I paint it with majick marker, reassemble the lock and work it a few times. Then dissasemble and look for marks where the internals are dragging. I work these one at a time until all are polished and no longer show drag marks. This often takes some time so patience is required.
As far as springs I want my lock balanced, meaning the frizzen spring isn't so strong it jars the rifle when fired. I don't want to alter the strength of the mainspring if at all possible to insure speed and good hammer strikes.
I check for any binding of the frizzen, and for a too wobbly frizzen. Next I check the weight required to open the frizzen, I like my frizzen to open at 3 lbs. as measured with a trigger gauge. This number works best for me with set triggers.
I will also remove and polish any parting gates remaining from casting on the mainspring.
Then I start shooting the gun and hopefully I'm done.
American horses of Arabian descent.

Offline deepcreekdale

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Re: Tuning locks
« Reply #10 on: August 07, 2018, 10:59:41 PM »
Hershel House has a useful short video on his blacksmithing basics DVD # 1, it is available from Muzzleloader Magazine. It might be helpful to have something to look at if you are a beginner. He shows some of the wear points and places to look for problems.
”Far and away the best prize that life has to offer is the chance to work hard at work worth doing.” Theodore Roosevelt

Offline kudu

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Re: Tuning locks
« Reply #11 on: August 08, 2018, 12:17:33 AM »
Well Im no expert But Ive been a Journeyman Machinist for 25 years and have my own shop at my home.
and have made a few things one being a Mule Ear lock.

The lock I shoot Now is a L&R Manton, Flint, and I just about have it wore out in two years shooting.
I took in all apart this weekend and all the tolerances are getting to loose. I shoot alot sometimes 150 rounds in a weekend, but two years!
 I literally dip the lock in oil every time Im home and blow the excess off so I Know its not lack of lubrication. It lives "The Lock" in WD - 40
I made the gun myself and choose the lock over a small "siler" no particular reason the cost was about the same.

The parts that have high wear just arn't hard enough I.E the hole thru the lock plate and the same hole in the bridle not the sear hole. But the axle hole for the main tumbler/cock pin.

Dont even ask about the side to side play on the Frizzen.   

I think the parts should be at or around 50-55 Rockwell on the C scale.
made out of a nice tool steel O1 comes to mind or A2.

It may cost more, but not too much more after the CNC is setup and proved out those little parts switched to a good steel instead of a casting would be worth it to me.

Offline Bob Roller

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Re: Tuning locks
« Reply #12 on: August 08, 2018, 02:01:46 AM »
Well Im no expert But Ive been a Journeyman Machinist for 25 years and have my own shop at my home.
and have made a few things one being a Mule Ear lock.

The lock I shoot Now is a L&R Manton, Flint, and I just about have it wore out in two years shooting.
I took in all apart this weekend and all the tolerances are getting to loose. I shoot alot sometimes 150 rounds in a weekend, but two years!
 I literally dip the lock in oil every time Im home and blow the excess off so I Know its not lack of lubrication. It lives "The Lock" in WD - 40
I made the gun myself and choose the lock over a small "siler" no particular reason the cost was about the same.

The parts that have high wear just arn't hard enough I.E the hole thru the lock plate and the same hole in the bridle not the sear hole. But the axle hole for the main tumbler/cock pin.

Dont even ask about the side to side play on the Frizzen.   

I think the parts should be at or around 50-55 Rockwell on the C scale.
made out of a nice tool steel O1 comes to mind or A2.

It may cost more, but not too much more after the CNC is setup and proved out those little parts switched to a good steel instead of a casting would be worth it to me.

I have made up a number of locks using the L&R Small Manton-Durs Egg and Ashmore and I make precisely fit
mechanisms for them and I use 0-1 for the sear and fly and 1144 Stressproof for the tumbler.Also plate and bridle
and sear screw holes are reamed after drilling. Forged main and sear springs,frizzen spring seems to be OK but the
one on the Ashmore is not as pleasing to look at so I will adopt the Chambers late Ketland frizzen spring as I did on
one I sent to a customer a while back. Looks really good and better functioning. Beginning in the late 60's and early
70's the lock on any muzzle loader being built had to be the cheapest thing in the gun.I used to get requests almost
daily to make new mainsprings but turned them down.I usually said,"You get what you paid for" and one long time
dealer asked for quality mainsprings for the earlier Siler locks but that was another one I wasn't interested in.
Involvement with other shops and high end import car repair kept me busy and in the late 70's I sent a sample lock
to Guenter Stifter and Helmut Mohr in Germany and that kept me as busy as I wanted to be and I still worked with
the cars as often as possible.The man who got me interested in cars at age 16 was Raydon R.(Don)Thompson who had
when I first met him,two Model "J"Duesenberg cars in a garage and he let me help him with small jobs and in later years
was the owner of European Motors which was a shop for any and all cars from Europe and I helped him a lot more in
later years.These "Euroklunkers" as I call them are the reason we have owned 6 Lincolns in our 49 year marriage.

Bob Roller
« Last Edit: August 08, 2018, 03:10:04 PM by Bob Roller »

Offline Davemuzz

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Re: Tuning locks
« Reply #13 on: August 12, 2018, 10:18:58 PM »
... and for a too wobbly frizzen. ...

How do you fix a wobbly frizzen?

Offline rich pierce

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Re: Tuning locks
« Reply #14 on: August 13, 2018, 03:31:38 AM »
A wobbly frizzen is not a huge problem unless you have poor frizzen cover to pan fit as a consequence.  It may even (crazy talk) be an advantage because the frizzen will self-align to the flint.  I know, crazy talk.

To fix, you need to diagnose, and decide if you are a machinist, welder, and heat treater or not.

1) What is the current diameter of the pivot screw where it pivots?  Is it undersized and worn?

2) What is the current condition and diameter of the pivot hole in the frizzen?  Use number drills to estimate. Is it out of round?

3) Is there excessive side to side slop of the frizzen? Is it bridled or unbridled?

Obviously 1 and 2 above work together. It is more common in my experience for the hole in the frizzen for the pivot screw to get cobbed up than the pivot screw.  Replace the frizzen or weld up the pivot hole and re-drill.  Or replace the pivot screw. Or both.

I would not worry as much about #3 but your repair depends on whether it is bridled or not..
St. Louis, Missouri

Offline Darkhorse

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Re: Tuning locks
« Reply #15 on: August 13, 2018, 05:38:15 AM »
Try this first, tighten the frizzen screw (if you can) until the  frizzen is noticably harder to open, most of the wobble should be gone. Now back out the frizzen screw a little at a time until the frizzen opens freely again and stop there. Does the frizzen still wobble too much? If it is not marking the barrel and prime is not escaping from the pan (assuming you have achieved a tight pan to frizzen fit) then it's not wobbling too much.
Try it you might get lucky. If this doesn't fix your problem then refer back to Rich's previous post.
American horses of Arabian descent.