Rehardening frizzens - one size fits all? Musings for metallurgy masterminds....

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A couple thousandths are plenty for lock plates and tumblers and sears. Frizzens wear more. When I deep pack case harden I add mild steel tie wire 1/16” thick. After quenching it snaps like glass and so it must penetrate pretty deep.
I made an interesting discovery/observation some years ago on charcoal case hardening depth by accident. I was using some shim stock for blocking and after roughly six cycles of use on various rifle actions I was casing I decided to see how far the carbon had penetrated by bending (worry-ing) the shim stock until it broke. Even after half a dozen case cycles in bone and hardwood charcoal mix the skin had only penetrated maybe .005- .006 , The core was still completely soft and malleable.
 
There’s waay too much hardening of frizzens by people with very little experience in hardening and tempering steel and who don’t have much knowledge outside of what they get online.

First is assuming the frizzen needs hardening. Not getting sparks? TEST for frizzen hardness before deciding that’s the issue.

Second is not understanding the limitations of kasenit and cherry red, as outlined above. It hardens less than paper thin. But there’s always the possibility that the frizzen had enough carbon to harden through and through when surface hardening and quenching.

Then there are those who don’t think tempering is required, especially at the toe and where the face meets the pan cover.

We are in the times of YouTube and Internet forums where many think they can get a bit of advice and do anything. It’s easy to end up worse off than before the “fix” was started.
Well stated Rich :thumb:
 
I made an interesting discovery/observation some years ago on charcoal case hardening depth by accident. I was using some shim stock for blocking and after roughly six cycles of use on various rifle actions I was casing I decided to see how far the carbon had penetrated by bending (worry-ing) the shim stock until it broke. Even after half a dozen case cycles in bone and hardwood charcoal mix the skin had only penetrated maybe .005- .006 , The core was still completely soft and malleable.
Had it been water quenched directly from the forge?
 
A couple thousandths are plenty for lock plates and tumblers and sears. Frizzens wear more. When I deep pack case harden I add mild steel tie wire 1/16” thick. After quenching it snaps like glass and so it must penetrate pretty deep.
Jerry Huddleston once said he could get as much as 1/32" depth on some parts, but said he wasn't sure if he get more than that, and I think he said .020 was not a problem.
 
Jerry Huddleston once said he could get as much as 1/32" depth on some parts, but said he wasn't sure if he get more than that, and I think he said .020 was not a problem.

I often hear people say they desire parts to be through hardened, as in 100%. Does this need to be achieved with industrial equipment? Rather than small shop equipment?
 
I often hear people say they desire parts to be through hardened, as in 100%. Does this need to be achieved with industrial equipment? Rather than small shop equipment?
I believe that depends more on the alloy. 1095 is not considered a through hardening steel. About 3/16" is what I have read from most bladesmiths for 1095, but I believe O1 is or is close to be considered though hardening because of the alloys in it. It is my assumption, in general, steels requiring a fast cooling quench are not deep hardening because of the short time involved in the quench in order to beat or lessen the formation of pearlite.
 
Results pending on lock kit from 1972

Tips from fellow forum members who are more up to date on this process are much appreciated :thumb:

This was a lock kit minus the sear & fly I acquired years ago while actively building & restoring muzzleloading
firearms in my then well equipped shop.
Current shop is now a spare bedroom equipped with a couple workbenches, gunsmithing tools I kept & lots of hand files since
downsizing 3 years ago due to age & health issues.

Hardening & tempering process I'm using,, results pending.
I'm using a propane torch with a concentrated tip with propane as fuel & Cherry Red to do the surface hardening,
my container of Kasnit must still be packed from our move.


After making a new sear & fly that were missing, all components were fitted & polished for best function,
the springs were already tempered.
*Apologies, didn't think to take photos of the assembled & polished lock prior to hardening & tempering
All screws were heated to a royal blue & dipped in canola oil.
Photo shows parts after being heated to cherry red, dipped in Cherry Red & quinched in Canola oil.
** Toe & pan area of the frizzen was held by a wide jaw pair of vise grips to try & prevent overharding & risk of breakage where the frizzen & pan area merge.
**Lock plate TIP; To avoid warpage of long thin parts,,, hang, heat & 'quench' vertical while suspended on a wire.
TIP; The hardening compound Cherry Red leaves a hard to remove crust on parts.
On a lark I found that soaking the already cooled lock components in rubbing alcohol overnight has made removal
of the messy & stubborn crust much easier !
>Photos; show the lock's springs & fire blued screws along with blackened parts after removal of the hardening crust.
Parts will tempered at 400 degrees on a cookie sheet in kitchen oven for an hour.
 

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Results pending on lock kit from 1972

Tips from fellow forum members who are more up to date on this process are much appreciated :thumb:

This was a lock kit minus the sear & fly I acquired years ago while actively building & restoring muzzleloading
firearms in my then well equipped shop.
Current shop is now a spare bedroom equipped with a couple workbenches, gunsmithing tools I kept & lots of hand files since
downsizing 3 years ago due to age & health issues.

Hardening & tempering process I'm using,, results pending.
I'm using a propane torch with a concentrated tip with propane as fuel & Cherry Red to do the surface hardening,
my container of Kasnit must still be packed from our move.


After making a new sear & fly that were missing, all components were fitted & polished for best function,
the springs were already tempered.
*Apologies, didn't think to take photos of the assembled & polished lock prior to hardening & tempering
All screws were heated to a royal blue & dipped in canola oil.
Photo shows parts after being heated to cherry red, dipped in Cherry Red & quinched in Canola oil.
** Toe & pan area of the frizzen was held by a wide jaw pair of vise grips to try & prevent overharding & risk of breakage where the frizzen & pan area merge.
**Lock plate TIP; To avoid warpage of long thin parts,,, hang, heat & 'quench' vertical while suspended on a wire.
TIP; The hardening compound Cherry Red leaves a hard to remove crust on parts.
On a lark I found that soaking the already cooled lock components in rubbing alcohol overnight has made removal
of the messy & stubborn crust much easier !
>Photos; show the lock's springs & fire blued screws along with blackened parts after removal of the hardening crust.
Parts will tempered at 400 degrees on a cookie sheet in kitchen oven for an hour.

OOPS ☹️
All parts cleaned up great except the lock plate.
I had polished the lock plate & all components prior to starting hardening & tempering.
All came out perfect except the 'hardened' lock plate now has shallow freckling on both sides due to surface carbon loss.
Be very pleased if anyone has instructions on how to encourage the carbon gremlins to return home to save me resurfacing labor 😁
Once lock plate is finished I'll assemble & post how sparky the lock is.
 

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I harden plates to speed up lock time & hardened & quenched the plate vertically to avoid warpage & that worked.
Sometimes the bird of paradise flys up yer who-haw :dunno:
Always best to have a plan B ready.
 
I had my frizzen for my .50 harden, last year. Worked fine for a few shots, at a event where i was talking about flintlocks, went to cock the gun and the frizzen broke at the heal.
Who ever hardened it didn't temper it after coating and hardening the frizzen. Don't use that gunsmith again.
 
1) They are super narrow. Can’t think of many frizzens that narrow.
2) Not all hacksaw blades are simple high carbon steels with predictable, simple heat treating and tempering requirements
Ok, but begs the question, why do so many claim how well hacksaw blades work? Personally, have a small oven and just case harden any frizzens that need help, then draw back. I know the Kasnet and Cherry Red creates no more that .001” to .002” case hardening if their instructions are followed, so almost useless for frizzens in my opinion, unless frizzen steel is hardenable. Curious why so many claim low temp soldering to a frizzen of hacksaw blades are an answer?

If I were to use a hacksaw blade, I would use one of the ‘all hard molybdenum’ industrial ones that I have a drawer full of. Figure I would grind to shape and use a low temp high strength silver solder to attach. No post solder heat treat required. But I have to admit, I haven’t tried it, but it is on my low priority to do list. Believe they are wide and hard enough. At least they cut most any soft steel, including 4140 pre hardened (RC 30) without issue. Recently retired, so no current access to hardness tester to confirm actual hardness.
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One thing that I haven't seen mentioned is the annealing of the arm of the frizzen after hardening the entire piece and not just the face, to relieve brittleness and prevent breaking or cracking in operation. Is that something anyone worries about?
 

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