blocks for hardening lockplates

[J.D.]

I made a block for hardening a coupla lockplates and was wondering how y'all block the plates you harden, to prevent warpage.

The block was made of 3/8 square stock, cut to the length of the plate. Holes were drilled for mounting screws but only two holes on the plate line up with the block. Only the forward lock bolt and sear screw holes line up with the block.

In this case, I'm not necessarily after colors, so the block sits directly on the outside of the plate. Do y'all block the inside of the plate, in addition to the outside, to prevent warpage, or does everyone only use one block?

Is 3/8 square stock wide enough to prevent warpage?

Just trying to flatten the learning curve, a bit.

Thanks and God bless,
J.D.

[Rolf]

Jerrry, if the block is on the inside of the lock plate, won't this stop the kasenite from hardning this side of the plate?

Best regards

Rlfkt

[J. Talbert]

Jerry,
When you say that you "go thru" the hammer hole, do you mean that you put a bolt thru the tumbler hole?  If so, would this not block carbon absorption to a part where you most want it, or am I misunderstanding something?

Thanks
Jeff

[J.D.]

Thanks Jerry, that is a big help. I think I have a piece of 3/8 plate that might work. Using small nuts for spacers is a great idea too. Never thought of that.

Does the plating on the nuts affect the case colors...in the event that I happen to get some colors? Or do you burn the plating off before blocking a plate?

I assume, and yes, I know all about making assumptions, that carbon will migrate through the inside of the plate to harden the tumbler hole, in the plate.

Or, maybe the bolt going through a spacer cut with a concavity into the bottom to allow carbon to find it way into the tumbler axle hole?

Just kinda think'n...typ'n out loud, so to speak...type.

God bless

[J.D.]

Thank you for that information, Jerry, that is what I was looking for. You are truly a wealth of information.

Rolfkt,

I'm not an expert on pack hardening, so I'm probably not the best person to answer your question, however, Kasnsit isn't used in pack hardening. Parts are packed in a crucible with wood charcoal, charred leather, and charred bone meal, in any or all of those combinations. The crucible is then covered with a loose lid and placed in a furnace to heat to 1550 degrees for as long as necessary to get the depth of hardening required, for that part.

There are several threads in the old archives on pack hardening, case hardening, and color case hardening that explain the process much better than I can. A good place to start is with the "Casehardening with bonemeal" thread.

God bless.

[Acer Saccharum]

Rofkt and Jeff bring up a good point about the carbon getting into the tumbler hole.

What I wonder is this: when the parts are in the closed crucible, does the carbon enter because it is a carbon rich ATMOSPHERE? Or from contact with carbon only?

C'mon you scientist gun builders .......  What say you?

It might require some experimentation.


By the way, I use tubing spacers between the lockplate and the backer bar. perhaps some cross holes drilled in the tubing spacers would allow the carbon to enter the tumbler hole.

[Z. Buck]

ok Acer, my SWAG (scientific wild a$$ guess) as an amateur  is that it is the atmosphere just like in a torch or forge there is a section of the flame that adds carbon, a part that removes carbon, and part that is neutral, without metal testing equipment it would be hard to tell, but my basis for this guess other than reading old books on forging, is from when i used to work in a glass blowing shop and made little beads and what not, in a torch flame if you held glass rod in the right place it would actually absorb carbon and get to look like black chrome or really highly polished graphite, neat effect but hard to control, also happened a few times when i didn't want it to... anyways that is the end of my conjecture for the night

[Acer Saccharum]

Zack, without having the proof to back it up, my guess, too, is that it's a carbon rich atmosphere that will permeate every nook and cranny within the crucible. As long as the steel is the right temperature, it will absorb the carbon.

That's my guess.

Somebody please set me straight.

Acer

[Acer Saccharum]

The backer bar gets casehardened too, so do all the steel screws you use. Use new screws every time because they get brittle after one time through.

Jerry, do you use stainless screws? I assume they are not as affected by the heating/cooling?

The backer I use is 1/4" x 1 1/2" x 6. It's too hard to drill now. I'd have to anneal it if I want to put different holes in it.

[J.D.]

Screws on the lock being hardened need to be hardened too, so why not use lock screws that might be long enough, to secure the block?

Granted, most lock screws aren't long enough to secure the block to the plate, but some large locks have a screw or two that are long enough, so why not use them?