Spring steel question

[James]

Kit Ravenshear's booklet on springs suggests using steel in the 1070 range for lock springs. Dixie sells spring stock that he states is in the 1060-1080 range. I am curious if a resident metal expert could tell me what sorts of scrap steel items would be acceptable to forge into springs. I have many types of scrap steel, but don't know what the rating of them is, i.e. auto coil springs, modern and antique hay rake tines, leaf springs etc. I would rather use something I have on hand that I can forge into flat stock to make springs from, rather than buy it. What would work the best?
Thank you for your time,
 Jim

[44-henry]

Any former spring has potential as do other high carbon tool scraps (old files, knife blades, some saw blades, etc.). I am sure early smiths re-used scrap for such purposes so can you. That being said I think it is far easier, and more predictable, to use known alloys. Several suppliers other than those mentioned (Enco for example) offer inexpensive flat ground tool steel stock that would be a better choice. If you purchase from one of these suppliers at least you know exactly what you are getting and can select the best heat treatment for it as well.

[wilkie]

I've used lawn mower blades with good sucess.  Carbon steel hacksaw blades will work for small springs.  Cut a small strip of steel, heat red hot, then quench in water to harden it, then clamp in a vise and hit it with a hammer.  If it is brittle and breaks like a piece of glass it can usually be used for a spring.

[Habu]

I tend to like pitchforks as a source of stock for musket springs.  Part of that is convenience (I can find one on most scrap piles around here), and part of it is that I just plain hate pitching hay.  Heat treat it like 1095.

[Acer Saccharum]

Take a small piece of the steel in question, and heat treat it. see how it performs before you put a whole bunch of work into making a spring.

[Dave B]

I saved this when one of our members here posted it for us. Its a list of what common junk yard stuff is made from.


once you know the make up you can determine how it needs to be treated.

[rich pierce]

I used that chart when I did some toolmaking and springmaking but question that cold rolled steel is 1070.  I used old ag steel quite a but with success.  Hay rake tines, dump rake tines, harrow blades, all harden well and make decent tools and springs.  It's fun to re-purpose but easier to buy spring steel.

[Hungry Horse]

I like pitchfork tines for main springs, I use old fish tapes bought at yard sales. they are usually in pretty good shape, because they are usually kept oiled, and make nice sear springs, patchbox springs, frizzen springs, and even revolver springs.

                 Hungry Horse

[flintriflesmith]

Years ago we ended up making 3 or 4 mainsprings for the same lock before we figured out that the auto leaf spring scrap we had was from a differnt car and was some sort of "air hardening steel." The time wasted far exceded the cost of new steel.

In the 18th and 19th centuries steel bar stock was found in stores even out in the backcountry.
Gary

[doug]

    I have made somewhere around 50 mainsprings and use almost exclusively drill rod (guessing 1095).  I forge it to a bit over thickness and grind and file it etc from there.  It has always been very dependable for me.  Recently I tried making a very wide mainspring (over 1" wide) for a miquelet lock out of an automotive leaf spring.  While I was able make it springy, it was still too brittle and both tries broke.  I did what I should have done in the first place; coughed up with the money and bought some 5/8" drill rod.  That spring worked 100%.

    Garden shovels are a high carbon steel and should work for smaller springs, but I can't remember if I have ever used them for that purpose

cheers Doug

[Bob Roller]

Doug,
Contact me at <bobroller@frontier.com>.

Bob Roller

[Jim Kibler]

If the spring isn't being used in a very demanding location you can get away with a lot of different alloys and heat treatments.  When you push a spring to the limits, you better know what it is made of and how to heat treat it.  Of all the springs associated with a flintlock firearm, the mainspring is of course the most highly stressed.  I know the crowd associated with the stuff likes to re-use etc. but it really does pay to buy a known proper material first and then perform a proper heat treatment.  The time spent in this stuff far outweighs the price of the material.

 

[JCKelly]

buy some 1070
sell the scrap springs to the scrap yard

Lawn mower blades used to be AISI 1070, quenched in molten salt to about a Rockwell C 40 hardness. Would be a good spring steel.

Them was the old days. Now, at least for the US, lawnmower blades are 10B35, makes a tougher blade but not such a good spring.

Whatever the steel, if you FORGE it to shape you MUST MUST ANNEAL or NORMALIZE it before hardening  tempering. This is necessary to refine the grain size, which grew to Lord knows what size here & there during forging. For a few shots it does not matter, But if you want your forged anything to work a long time & be tough, you gotta heat it maybe 1500 - 1650F and air cool (that is "normalizing", the normal way to cool something, just let it cool in air). Or, for higher carbon steels one must anneal. Fine grained metal always works better than coarse grained (you gas turbine blade guys of course look at it differently)

Perhaps I spoke to strongly. "MUST" doesn't really come in to it, unless you want the thing to perform the best it can.

Text Book Metallurgy that works.

[Dphariss]

I bought some 1070 and it works really nice hot easier then 1095. Prefer it.
You can get all sorts of steel from pitchforks to car springs that will make a spring. Allen wrenches will make springs.
Buying flat stock with a good finish, proper alloy and close to the size needed is more cost effective and less frustrating.
For example a significant number of old buggy and wagon seat springs are AIR HARDENING and this can result in ruined files and hacksaw blades even with a standard annealing process.
I buy 1018 for lock plates, trigger bars, casehardened parts etc and 1070 for springs or use some of a 1/8 x 1 bar of 1095 I have from years back, which is bad enough, its hot rolled and requires annealing to cut without fear and has a hot rolled finish that is hard on tools as well. The extra labor and tool wear involved with making springs and other parts from  scrap make it counter productive.

Dan

[Acer Saccharum]

Dan, there is a lot to be said for working with a known entity, especially if you'll be putting long hours into making a spring.

[Bob Roller]

 I fully agree with Dan.Buying something of known provenence
is the only way to go when it comes to spring making. I have used 1075 for decades
and so far,only one failure and I think that spring was tampered with. Until recently,
I had it and the color was odd looking. For years,I sent a lot of locks out of the USA
and I HAD to have a spring steel that was uniform and for me,1075 is it. I wouldn't
ever attempt making springs from drill rod or pitch fork tines or anything else. Years ago,
one lock maker used 1095 and made tumblers from Chrysler and Packard torsion bars.
For tumblers, I use 1144. It machines almost like 12L14 and will harden in oil when heated
and quenched. Methods and mmaerials may vary a lot from person to person but I am
oriented to results and knowing that when I send a lock to where ever,it has good quality
springs and other parts.

Bob Roller

[James]

I see the general opinion and reasoning behind it. I was under the mistaken impression that the steel I have would be one alloy or another consistent with what it had been originally used for. I see your point that there is no way for me to know what the parts I have were made from and that for my needs I should know what I'm working with. Thank you.

[WadePatton]

I see the general opinion and reasoning behind it. I was under the mistaken impression that the steel I have would be one alloy or another consistent with what it had been originally used for. I see your point that there is no way for me to know what the parts I have were made from and that for my needs I should know what I'm working with. Thank you.

yes, the specific contents of the alloy-represented by the numeric designations, determine the characteristics of the alloy.  The most pertinent of those being how it responds to the various heat-treatments used to create a properly durable part. *

While i rather enjoy making shop tools (and other things) from scraps and worn files, but if a shop tool "fails" i just fix it or make another one.  I wouldn't want to have any "contributory responsibility"  in the field failure of a lock part.

* there's some real good reading in Machinery's Handbook wrt spring materials (and every other engineering aspect of a spring).

[Acer Saccharum]

Where can I get 1070 in small batches?

[Bob Roller]

Acer,
Try McMaster-Carr. I think they are in Norther Ohio.maybe Cleveland.
I bought 50 lbs of 1075 from Lapham-Hickey in Chicago recently in 1/8"
thickness for mainsprings. I tried several other steel suppliers that I once
bought from and they seemed hostile to a small shop like mine so I was
directed to Lapham-Hickey. SOME of these outfits will send a sample but
I don't recall which ones.

Bob Roller

[Acer Saccharum]

Thanks, Bob. McMaster sells only 1095. I'll look at MSC.

[WadePatton]

Thanks, Bob. McMaster sells only 1095. I'll look at MSC.

admiralsteel(.com) has some 1075.

[Bob Roller]

My last experience with Admiral Steel was that they were not intetested in small shops or orders.
 Bob Roller

[T*O*F]

Flat spring stock assortment-1075 steel

http://www.brownells.com/.aspx/pid=26219/Product/NO-149-FLAT-SPRING-STOCK

[Dphariss]

I think DGW sells 1070-1075 1" wide by 12" long.
At least is was 1070 a few years back.
Dan