Case Hardened - Aftermarket Siler Type Screws...

[Chris Evrard]

Hey All,

It has been a while since I posted. About a year! Anyhow I had an idea a few years back to try making case hardened screw sets for Siler locks.

Now I know full well that no one in THIS forum would EVER wallow out a screw slot!!! Myself included..... ha,ha,ha,ha! But you never know about that rascally fellow who buys or gets his hands on your rifle after the fact. Chris Laubach and I refer to this fellow euphemistically as "Bubba."

Anyhow, I talked to Bodycote (my local metal "treatments" place) about case hardening 12L14 screws to a depth of about .003-.004. The idea is to resist deformation of the screws during the myriad of assemblies and disassemblies performed during the building of a rifle, while still retaining the core strength of the screw, keeping it from being brittle all the way through.

It would also have the benefit of prolonging the slot in the top jaw screw, which will be horsed on regularly for flint changes, adjustments, etc. In addition the frizzen and sear would ride/rotate/pivot on hardened screw surfaces, which could have some added benefit as well.

Anyhow, I was curious to get the thoughts of you rifle builders out there. Do you all think there would be a benefit? No benefit? Any thoughts at all?

Full Disclosure! I have started making 150 sets of these screws as a test. Nothing is for sale yet (and may never be if it doesn't work out!!! Ha!) I know price of the kits would be the most pivotal factor. In my initial calculations I was coming up with a $40-$45 price range.

Oh and I should also mention that these screws are single point cnc turned, the finish is great to start out with, but they could be polished to a brilliant shine with very little work, and without compromising the hardened surface. Each thread is single pointed as well. I will include a link to a Youtube vid of some shop work on them below.

Again, curious for any thoughts!

Youtube vid.....



Best

Chris Evrard

[Craig Wilcox]

Nice shop there, Chris.  I'm afraid my machining is limited to my files and my Foredom!

[davec2]

Chris,

For what it's worth, I case harden the heads of all of the screws on any of my guns (i.e. butt plate, lock bolts, tang bolt, top jaw, cock, etc....) just to keep the slots from deforming.  I like your idea.  Don't know if it will sell, but I like it.

[wattlebuster]

Very interesting video. Your work looks to be very precise. No wonder the Virginia lock I bought from you is so smooth an sparks like a welder

[Daryl]

Chris,

For what it's worth, I case harden the heads of all of the screws on any of my guns (i.e. butt plate, lock bolts, tang bolt, top jaw, cock, etc....) just to keep the slots from deforming.  I like your idea.  Don't know if it will sell, but I like it.

As does Taylor - an automatic step in gun building.

[P.W.Berkuta]

Impressive  . Is there a market out there for them ---  . I know for sure buggered up screw slots are the sign of "Bubba" at work. I case harden all my lock screws and other gun screws with the old formula of Kasenit which I have enough to last my life time. For the average Joe gun owner I think he would buy them but that would be only one set per gun lock. Maybe he has 3 guns but his income will only allow him to buy one set ---. Not every gun has Siler locks and also some folks just don't care if they bugger up screws. I guess you just have to test the water and see what happens

[Scota4570]

You're probably way ahead of me, but by two thoughts are: Polish them by tumbling to even up the finish and obliterate the machine marks.  Then pack harden them in mass, probably bone meal and or with ferriocyanide (sp?).  No colors needed. 

Great shop!  It is like a candy store of  machine tools. 

[Chris Evrard]

Very interesting video. Your work looks to be very precise. No wonder the Virginia lock I bought from you is so smooth an sparks like a welder

You are very kind. Thank you!

[Chris Evrard]

You're probably way ahead of me, but by two thoughts are: Polish them by tumbling to even up the finish and obliterate the machine marks.  Then pack harden them in mass, probably bone meal and or with ferriocyanide (sp?).  No colors needed. 

Great shop!  It is like a candy store of  machine tools.

Great minds and all.............Lol.

I am experimenting with wet tumbling to remove what little machine marks exist. They come off the lathe almost ready to go. That is the benefit of a high positive rake insert like the one I use. You can get some great finishes in 12L14, even if the insert doesn't last quite as long. Really the only machine marks are on the head from the cut off tool. And that is what I am experimenting with the wet tumbling and ceramic media for.

As for hardening en masse, That is what Bodycote will do. They can give me a precise hardened depth. They use a gas process in atmospherically controlled furnace. The screws come out looking kind of gun metal gray.

I must admit I do love my shop, which I guess is a good thing as I have to spend 50 hours a week there!

Best,

CE

[Chris Evrard]

Attached is a close up of a sear screw so you can see just how clean they come off the lathe......

Not much polishing to do at all.

[Bob Roller]

I always thought "Bubba" was a guy that will never get out of prison,has the IQ of a potted plant
and can throw King Kong out of a saloon and occasionally "married" someone who likes children
in an unacceptable way. .
Bob Roller

[Rawhide Rick]

I always thought "Bubba" was a guy that will never get out of prison,has the IQ of a potted plant
and can throw King Kong out of a saloon and occasionally "married" someone who likes children
in an unacceptable way. .
Bob Roller

I can’t offer anything to the discussion, but that was funny.

[Curtis]

Excellent idea Chris, only time will tell if the market will bear the price point. Looks like high quality work! 


Curtis

[Jim Kibler]

You might consider flipping the screw around so that the head is furthest from the spindle. It might make turning a little trickier, but your head will be exposed and can be finely finished.  I believe Omniturn sells a live tool as well that could be used to slot in the lathe.  Use an angled part off tool in order that a minimal tit is created and you might be able to finish these in one operation. 

Jim

[Dphariss]

At final assembly I either clean up the heads the assembly screws or fit new ones then caseharden them. However, it is best the draw them back to a blue temper since I have occasionally had them chip at the edges of the screw slot if not tempered. I suppose that straw color would work too.
Dan

[Chris Evrard]

You might consider flipping the screw around so that the head is furthest from the spindle. It might make turning a little trickier, but your head will be exposed and can be finely finished.  I believe Omniturn sells a live tool as well that could be used to slot in the lathe.  Use an angled part off tool in order that a minimal tit is created and you might be able to finish these in one operation. 

Jim

One op would be great, although I've never been able to figure out a way. There will be a tit on the part no matter what. The part off tool used is an angled insert. It minimizes but doesn't eliminate the tit in this material, at this diameter, etc.

The tit on the head is removed during slotting so you get a "free" op. Removing the tit on the threaded end would be a major pita and would have implications for the thread as well.

Anyhow the head finish is pretty killer to begin with.

[Bob Roller]

My locks in years long gone had drill rod screws until I bought a bunch of 12L14
bars that were .157 diameter which is the same size as the drill rod I used.
I have always tried to copy the English screws as found in their high end locks
and never hardened any of them.They were also mostly 4x40 threads and some
were 4x48.One thing I have noticed about the people on this forum is that most
seem to go for better rather than cheaper so offering upgraded screws should fit
right in.
I also don't remember when I quit the drill rod and went to 12L14 for lock screws
but do remember the company I bought the 12L14 from was closing and I bought
all the .157 they had for very little money .
Bob Roller

[Tim]

What hardening compound do you guys recommend a guy use to case
Harden the tang and cock screws on my Kibler SMR kit.
My rifle came with a chambers late Ketland lock.