Author Topic: Chambers' top jaw screw (Read 6094 times)

D. Taylor Sapergia · « **on:** November 25, 2017, 05:41:28 AM »

...cannot be case hardened!!! It, apparently, is high carbon steel already. In the process of case hardening the screws for my Kibler kit build, I included the top jaw screw. I got it hard alright!! My advise: don't.

smylee grouch · « **Reply #1 on:** November 25, 2017, 05:49:21 AM »

Yike's , never dreamed that those would be that hard. I have used that lock on several rifles but never tried to harden them. Glad I didn't. Thanks for posting.

flinchrocket · « **Reply #2 on:** November 25, 2017, 06:21:44 AM »

Could that be caused from some ceramic contamination during the casting process?

rich pierce · « **Reply #3 on:** November 25, 2017, 06:35:28 AM »

Looks just like perfectly hard steel, not tempered, when it snaps, like a file.

SingleMalt · « **Reply #4 on:** November 25, 2017, 07:08:14 AM »

Who'd have thought?

bob in the woods · « **Reply #5 on:** November 25, 2017, 07:29:16 AM »

That may be true of the top jaw screw alone. My experience in the past , with the other lock screws, is that they are rather soft. I've fire blued a few of these top jaw screws, but never have case hardened them . Was the case hardening done in a container, and then quenched, or did you use something like kasenit on it ? I usually use kasenit on the cock, the frizzen, and the lock plate . Never had any problems with the results. Thanks for sharing your experience .

Bob Roller · « **Reply #6 on:** November 25, 2017, 05:13:33 PM »

Quote from: SingleMalt on November 25, 2017, 07:08:14 AM

Who'd have thought?

I have made more than a few flint locks and never even thought about
hardening a top jaw screw.

Bob Roller

David Rase · « **Reply #7 on:** November 25, 2017, 06:55:27 PM »

Taylor,
I have color case hardened quite a few complete locks and just recently had my first casualty when a frizzen snapped. Did you draw back the part after hardening?

My first impression was of a cam shaft that broke into 3 pieces when I threw a rod in an old 292 ford Y block I once owned. Removed the timing chain cover and was able to remove the timing chain gear along with about a 4" stub of camshaft.... and then a smaller 3" section and then the rest of it.

Sorry about being off topic, seeing your 3 piece broken top jaw screw photo first thing this morning reminded me of a flash from my past.
David

D. Taylor Sapergia · « **Reply #8 on:** November 25, 2017, 07:43:57 PM »

I like to harden all lock screws, and have never had an issue before. The bridle, sear spring and sear screws are fine case hardened. I used a compound called "Hard and Tuff"...a green coloured powder that I got from a saw mill some thirty years ago. It really penetrates. But this top jaw screw was obviously tool steel, and should have been drawn to at least dark straw. I hope Jim Chambers will comment on the carbon content of the various screws in his locks. I had also done the cock screw - the one that retains the cock to the tumbler, but having ruined the top jaw screw, I tempered the hammer screw back to dark blue. All you need is a 6 x 40 hardened filler stud in your tumbler.

flinchrocket · « **Reply #9 on:** November 25, 2017, 08:08:21 PM »

A couple years ago I used the TOTW French Tulle lock assembled by Chambers. It was a really nice lock,but I am convinced the tumbler screw was stainless as it would not take any kind of browning solution. I'm sure it wouldn't case harden. Since then I've seen pictures of guns with that lock and they all have a shiny tumbler screw.

jerrywh · « **Reply #10 on:** November 25, 2017, 08:50:00 PM »

I case harden every screw on every lock I use but I always draw them back to about 400° Never had one break. I have had frizzens crack.

D. Taylor Sapergia · « **Reply #11 on:** November 26, 2017, 03:28:44 AM »

I drew this one to orange and quenched it in water @ room temperature. Like glass. Never again, perhaps.

Bob Roller · « **Reply #12 on:** November 26, 2017, 05:06:45 PM »

A lot of my locks had screws made from o-1 drill rod.
I have never heard of a bridle screw wearing out
or a sear screw either so never hardened them.
About 15 years ago I bought a lot of 12L14 that
was exactly the size .157 or 5/32 for lock screws
from a company that was going out of business'
I think some of the screws used by L&R are also
hardened so be careful there also.

Bob Roller

Jim Chambers · « **Reply #13 on:** November 26, 2017, 05:25:35 PM »

As far as I know our top jaw screws have always been made out of just plain old leaded screw stock, nothing else. Normally, the only problem we have with these is guys "dry firing" the lock without a flint in the jaws. This results in the top jaw screw being bend due to inertia. When the cock suddenly stops the large mass of the ball part of the screw tends to keep going resulting in a bent screw. But, I've never seen one of these break into three or even two pieces.
Now, Track of the Wolf has their own screw machine, and they have been making replacement screws rather than buying screws from us. God only knows what material they use in making their screws.

SingleMalt · « **Reply #14 on:** November 26, 2017, 05:55:42 PM »

Quote from: Jim Chambers on November 26, 2017, 05:25:35 PM

Now, Track of the Wolf has their own screw machine, and they have been making replacement screws rather than buying screws from us. God only knows what material they use in making their screws.

That's a nice bit of information to know. If I need a replacement screw, I'll go to the manufacturer rather than Track.

D. Taylor Sapergia · « **Reply #15 on:** November 26, 2017, 07:25:31 PM »

Thanks for replying Jim...good info. This screw came from my Kibler kit. The lock is finished nicer on the inside than usual...mainspring polished and beveled, for example. I like screws that are resistant to screw driver wear - that's why I harden them. but I'll know now to draw the temper @ 400 for an hour in the future. By the way,, the frizzen does not have a rebounding issue on this fine lock! Happy with that.

P.W.Berkuta · « **Reply #16 on:** November 26, 2017, 08:12:04 PM »

I have snapped several 10-32 tang screws below the 82 degree counter sink head after I casehardened them with the old Kasenit compound. I did not stress relief or temper them back after doing the case hardening.

Bob Roller · « **Reply #17 on:** November 26, 2017, 09:22:58 PM »

Quote from: Jim Chambers on November 26, 2017, 05:25:35 PM

As far as I know our top jaw screws have always been made out of just plain old leaded screw stock, nothing else. Normally, the only problem we have with these is guys "dry firing" the lock without a flint in the jaws. This results in the top jaw screw being bend due to inertia. When the cock suddenly stops the large mass of the ball part of the screw tends to keep going resulting in a bent screw. But, I've never seen one of these break into three or even two pieces.
Now, Track of the Wolf has their own screw machine, and they have been making replacement screws rather than buying screws from us. God only knows what material they use in making their screws.

Jim just described candidates for the BoneHead Award,snapping a flintlock with no flint or
wood dummy to take up the shock.TOW sent me a TVLLE flint lock kit a while back but I
have yet to hear why.David R told me about a new screw machine they had acquired for
their own shop.I may see if I can get that kit together but shop work is not a priority.
My wife has breast cancer,early stage but we are requesting a full body scan to see if
there are any more "suspects".Her energy level is way down from where it usually is.
.
Bob Roller

Robby · « **Reply #18 on:** November 26, 2017, 11:37:40 PM »

God bless you and your wife Bob. Best to you.
Robby

elkhorne · « **Reply #19 on:** November 27, 2017, 07:05:15 AM »

Bob,
Our prayers are with you and your wife. Cancer is a bad villain and too many people are fighting it but it gets very personal when it is someone very close that we love like our family members. I pray for peace and healing for you all and all I can say is trust God. Let us know how things go.
elkhorne

RockLock92 · « **Reply #20 on:** November 27, 2017, 07:58:37 AM »

Quote from: Bob Roller on November 26, 2017, 05:06:45 PM

A lot of my locks had screws made from o-1 drill rod.
I have never heard of a bridle screw wearing out
or a sear screw either so never hardened them.
About 15 years ago I bought a lot of 12L14 that
was exactly the size .157 or 5/32 for lock screws
from a company that was going out of business'
I think some of the screws used by L&R are also
hardened so be careful there also.

Bob Roller

I can verify that some L&R screws are. The rifle I’m working on now has an L&R lock (I didn’t know better at the time I purchased the components) and I had a hard time shortening the bridle screw because it was hardened and was digging into the cock. I wound up having to grind off the amount I was hoping to slowly file off. I’ll never buy another L&R lock again...

D. Taylor Sapergia · « **Reply #21 on:** November 27, 2017, 07:19:47 PM »

I made myself a jig plate out of 1/8" steel for shortening screws. Tap drill and thread the plate for the screws you frequently have to shorten. Run the screw into the plate, extending the amount to shorten, and grind them off. Removing the screw cleans up the burr.

smylee grouch · « **Reply #22 on:** November 27, 2017, 07:42:44 PM »

If you go to any good hardware store they will probably sell a "screw checker" plate much the same principal as Taylor's plate. These plates have many different sizes along with drill sizes that you can do what Taylor has done. Handy tool for sure but maybe not as durable as Taylor's.

D. Taylor Sapergia · « **Reply #23 on:** November 27, 2017, 07:55:57 PM »

Good tip SG. Mine started out at 1/4" and in places is down to 1/8". I use a 6 x 48" belt grinder to do the grinding, but one of the bench models with 1" belt would work fine too...or a disc sander mounted in a drill press...or

D. Taylor Sapergia · « **Reply #24 on:** November 27, 2017, 07:57:02 PM »

...and one of the nice features of L & R's locks is the nice quality hardened screws.

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Author Topic: Chambers' top jaw screw (Read 6094 times)