Metallurgy for Dummies

[Bill-52]

I'm working on a JP Beck patchbox release spring latch using photos in the ALR Museum and in various topics here as a guide.  Had some flat stock in the shop that seemed would work -- it didn't, it was too soft.  I clearly need to learn more about the properties of different metals.

I'm happy to pull myself up the learning curve.  Can someone recommend a good reference guide?  Or, a good source for metal to use on a spring latch (my father-in-law has a farm with a good supply of discarded metal).

Many thanks,
Bill

[44-henry]

You need to start with high carbon steel to make a spring and following that you will need to heat treat it. No shortage of information on these topics exist, if you want something in writing Howes Modern Gunsmith Volume 1 & 2 are good places to start with lots of information on this and other areas, though it pertains to more modern firearms (at least modern for the 1930's). You could salvage your steel from some items (old files, leaf springs, etc.) but you might just want to purchase a piece of known alloy and skip the guess work. I You can purchase flat ground 01 from a number of suppliers (Enco being one) and the stuff is relatively cheap and easy to work with.  Before I had access to more sophisticated heat treat equipment I made a spring for an underhammer action by heating the part just beyond a point where it lost its magnetic attraction and than quenched in a pail of old motor oil to harden it. I recall just hanging a magnet conveniently over my workbench and heating the part with an oxyacetylene torch, testing it every so often to see when the magnet wouldn't touch it. Following that I stuck the parts in a sardine can and covered them with the same oil I quenched in, heated this from the bottom with a propane torch until the oil boiled and than ignited it with the torch. I just kept relighting it until the oil burned completely off and the part was finished. It was crude, but it did work at least with simple tool steels. I will admit that it smoked something awful and wouldn't probably win the affection of your neighbors in town, but it did work (though I was somewhat hesitant the first time I tried this, half expecting to see my handmade spring break in two). The method works because the burning oil is about the right temperature for a spring temper. This method won't work with a lot of modern tool steels that require different temperature ranges, but still works fine with basic alloys.

[Jim Kibler]

For a catch spring like Beck used, the travel is small enough that a piece of mild steel will work fine.  No need for higher carbon material.  If your low carbon spring didn't work, I would think it was for other reasons.

[JDK]

I still find the small booklets by Kit Ravenshear invaluable.  They are still available through TOW and probably others and at about $6 a piece you can't beat the price.

Enjoy, J.D.

[b bogart]

A piece of metal banding (think shipping pallets etc) would do for that !

[Bernard]

Band saw blades are also good for making light springs. I make a lot of leaf type springs from pieces I cut off an old truck spring leaf. One of these leaves will last a long time.

[Jim Kibler]

The question was regarding the catch spring on a Beck styled rifle, not the kick open spring.  Material from banding stock, band saw blades etc., is much to thin.   Again, no need for any high carbon material or heat treatment.  A piece of mild steel will work fine.

[Dave B]

This may be over the top but it was helpful to me to know much more about what things are made from if you have these things in the pile at the farm.

[Long John]

Dave,

Thanks!  I saved that one!

John Cholin

[Don Getz]

Are you talking about a catch that has a button to push on the top, or heel of the buttplate?   If you are, as Bernie said
above, a piece of band saw blade works great.  After all, we are talking about moving a hook about 1/16"........Don

[Vomitus]

Grass and leaf rakes,the metal flimsy kind.

[Eric Smith]

Thanks Dave. I saved it , too.

[LRB]

  Mr Kibler is correct on this type of latch. There is no need whatever to use more than mild steel. Even a hammered out nail would work for this. The catch does not have to move far enough to need any more return power than mild steel offers. If your spring did not work, there has to be a reason other than the steel.

[JBlk]

If you are using salvage material for your projects a good rule of thumb is to determine what the application of the material was used for originally.If you are making springs look for something that had to flex yet not break such as pitchfork tines or hayrake teeth.The steel used for the most severe service will usually have the highest carbon content and be the hardest to work with.Go to your local library and see if they can get you a copy of Charles McRavens book entitled Country Blacksmithing.This book is out of print but it is written in a manner that you can easily understand and apply.

[JDK]

Grass and leaf rakes,the metal flimsy kind.

I saved ever one of these from an old broken rake....but I save everything.

I like them as they have plenty of spring and are thicker that hacksaw blades.  The width is adequate to make all sorts of stuff.

Enjoy, J.D.

[Jay Close]

In making door locks, both iron cased and stocklocks, I've used simple mild steel for spring that don't have much travel. The "trick" is to work harden them by hammering the spring cold. This will stiffen the metal and increase its "elastic limit" --- the amount it will bend and return to its original shape. I've even done this with true wrought iron. Works surprisingly well. Like anything, it can be over done and a crack develop, but you'll have a functioning spring well before that danger arises.

[Bill-52]

Thanks everybody for all the advice on fixing the problem, sources of information, and sources for appropriate steel, all of which is very helpful.  And thanks Dave for the Junkyard Steel table; this will be invaluable for sorting the steel at the farm.

Jim is correct.  My question is regarding the Beck style catch spring in which the button goes through the buttplate.  The travel to engage/disengage the hook going through the patchbox lid is very small.  There is an example in the ALR museum, second picture down, at:

http://americanlongrifles.org/forum/index.php?topic=4005.0

I suspect my error was in testing the flex in it's very roughed out form.  I'll finish the shaping and hammering and then test.

Again, thanks everybody.  I'm always grateful for the expertise here and open sharing of experience.

Bill

[Jim Kibler]

Although hammering to work harden wont hurt, it's not necessary on a spring such as this with so little travel.  The elastic limit will not be reached during the function of the spring.  Also, work hardening will have little effect on the stiffness of the spring. 

[bob in the woods]

I actually made one of these ' springs ', out of a piece of brass.  It works fine .