Frizzen Hardening

[White Oak]

This is a carry over from the flint lock forum on Allan locks. Wanted to ask questions and present my ideas here as this is where it seems to fit.Yes I will do a search on hardening but am looking for criticism on my method first.I have no experience with flint locks although I hope to own some one day. My current guns are all percussion.
Long story short, a friend has a frizzen that is either soft or low in carbon. Has asked me to harden it for him. I am a machinist and have the facilities to do so and agreed to try it. I have been given instructions about hardening it and judging the hardness by color during the process but having never done this feel more comfortable using what I know and altering it if necessary.
I understand that the frizzen should check between 50 and 60 on the Rockwell C scale. Plan on checking that first. Already checked it with a file and it appears soft.
Plan is to put it in the oven and bring it up to 1750 for 1 hour. We normally use 1 hour per inch of material thickness or 1 hour min. on thinner materials. After 1 hour, air quench only. This will bring tool steel up to about 64 rockwell.
Drawn back at 400 dergrees for 1 hour will bring the hardness down to about 55 give or take. Problem is I have no idea of the make up of the frizzen. I do not want to make it so brittle as to brake either.
There is no doubt that the problem is the frizzen. While I have no flint lock experience, the gun owner has been shooting them for years. The gun did fire when he acquired it about 10 years ago. No spark now.
Any suggestions, comments or criticism , constructive or otherwise will be welcome. Believe me, I can take it. :surrender:
Thanks in advance,
Ed

 

[rich pierce]

Usually O1 etc and an oil quench is recommended. Then check with a file. It should be glass hard. Then temper as you suggested all over in an oven then drawndown the hinge area and teat that rides on the spring to clock spring blue while keeping the frizzen face cool.

 

[Tumblernotch]

I've been using the method that Bud Siler recommended with his kit locks for years and I get a good spark. Heat the frizzen to a bright red and quench in clean oil. (I just use clean motor oil). After it's cooled, wipe off the oil and polish the face. Find a shallow pan or lid that you can put about 3/8" to 1/2" of clean sand on. Lay the frizzen on the sand so that you can see the face good. I usually put the lid on the kitchen stove burner but you can use a Coleman stove or whatever. Turn the heat on and keep an eye on the face. When it gets to a light straw color remove the frizzen from the heat and set aside to air cool. It will last for years because it's tempered all the way through.

 

[Zonie]

While reading thru your post I thought you were doing fine until you got to the "air quench".

Unless you are making a brand new frizzen out of air hardening tool steel, air quenching will not cause the metal to harden.

Most of the better locks have oil hardening steel frizzens so quenching it in 120-140 degree F oil is most likely to give you the hardness you are after.

Some of the old imported locks used case hardened low carbon steel.
With these frizzens a water quench is about the only way to get them to harden.
If the case is worn away, all the heating and quenching in the world won't harden them unless a new high carbon case is made.

I agree with the straw yellow temper on the upright part of the frizzen. A blue spring temper is good for the corner where the pan meets the upright face of the frizzen and the lower area that contacts the feather spring.

 

[dikman]

The reference to "air quench" has me slightly perplexed. Normally, if you bring most hardenable steels up to their critical temperature and let them cool in the air all that does is anneal them.
Generally, they need sudden cooling in either water or oil. I'm aware that earlier frizzens were case-hardened, but assumed that modern ones would use some sort of high-carbon steel, mainly because it's probably easier for the manufacturer to harden the whole thing rather than mess around with case-hardening a part of it.

Zonie appears to have confirmed my thoughts.

 

[LRB]

Your recipe is for air hardening tool steel. I don't know of anyone making frizzens from that steel. 1750° for an hour will produce large grain in simple steels and common tool steels, and you will have a weak structure. To play it safe, I would suggest a heat at 1475°, and a soak of 5 to 10 minutes, quench in a warmed thin oil such as canola. Temper at 375° for an hour. With a simple propane torch, heat the pivot area and tail to blue and try it out. Your other choices would be to pack harden or half sole it with 1095, or a piece of file steel.

 

[Vaino]

My guess is that it was case hardened and it's worn through.....tool steels are hardened through out their thickness. 50 RC is too soft for a frizzen striking surface.....slightly above 60RC is correct. Air hardening steels aren't suitable for frizzens....they spark less because of the chrome content.

Why not call Pete Allan and find out if he did indeed make the lock and what steel was used in the frizzen. He could also give you hardening and tempering instructions. Why guess?.

Also....did your friend try to harden the frizzen before giving it to you?......Fred

 

[White Oak]

Thanks everyone for the suggestions. After some discussion we changed our method completely. Maybe for the wrong reason but I believe it worked. My fear of heating the entire piece was making it brittle. We heated the frizzen face to red with a torch and held it at that temp for a short time. Oil quenched. Frizzen originally checked 40 RC. After quench checked 58 to 60. Not familiar with frizzen terms but the other portion or "leg " seemed uneffected and still checked around 40. I do believe that at its thickness it must be hardened all the way through. I can easily use the sand method here at home tomorrow.
I will find out early next week if we have sparks.
Answers : Great idea to contact Pete Allan. Not sure where to find him or positive that this is his piece but that is an excellent suggestion and if problems arise I will certainly try.
No, the owner has never tried to harden this.
As far as air quenching tool steel we do it regularly. May start out at 20RC and usually ends up at a max of 62-64 and is often drawn back for machining purposes. I realize that the frizzen is not tool steel. Not knowing what the material was is part of what caused me to rethink my method.What ever it is it seemed to accept the hardening quite well with a torch and oil.
I have to say that I believe a lot of dumb luck came my way on this one. Hardness seems to be there.Don't believe it was weakened anywhere in the process. Hopefully I can complete the face area and achieve the straw coloration.
Thanks again for all comments. Good or bad this has been a learning experience.
Take care,
Ed

 

[LRB]

If all you got was 58/60 Rc, you do not want to temper it. If the frizzen is indeed high carbon, which it may not be, you did not get it fully hardened, or the Rc tester gave a false read. That sounds like an Rc reading from a medium carbon steel like 4140, or similar type, if you are confident that you got as hard as it will get. Another possibility is from using a quench oil not matched to the steel, and it cooled too slow. You may not have had enough heat. "Brittle hard" is what you should be going for. That's why you temper afterwards. Judging heat by color is a poor way to go. Red color is subjective to the viewer. Not all see the same shade of red, and it takes practice and experimenting to be able to judge color closer than a 50° difference. In a low light setting, you can see red while the steel is below non-magnetic. Your aim should be one or two shades of red beyond non-magnetic.
What sort of Rc tester are you using?

 

[White Oak]

Not certain of the brand of tester. Is used by our QC dept. and was checked on a master before using. Quite certain the readings are correct. I was very hesitant to do this going by color only. As you say ,it would take a great deal of experience to do so. That I aint got.I agree that at that hardness it should not be tempered in hopes of keeping what we got. If that is enough?
This is why I originally had planned to use known temps and methods in this attempt. The big unknown was the makeup of the material. Hind sight being 20/20, I should have tried to contact the maker and learn more. Still not absolutely positive of who that is. I normally do not take on projects with unknowns like this. I presented all of the negative possabilities to the owner from a broken frizzen to at best no spark. He had no interest in going anywhere else with the gun.Said it hadn't fired in many years anyway. Believe me, if something goes terribly wrong I won't leave him hangin. I know it sounds like closing the barn door after the horse is out. Right now I believe the best I can do is try what I have and go from there. Thanks for the heads up on the tempering. I was thinking the same thing but would have gone ahead with it.
This has been a learning experience for me and with every post I learn more.
Thanks again,
Ed

 

[LRB]

The main reason I said don't temper was the hardness you got. Any softer and there just is not going to be much spark, if any. If you could get at or near 65 Rc, you would want a slight temper. Somewhere from from 375° to slightly more.

 

[Stophel]

Not all see the same shade of red, and it takes practice and experimenting to be able to judge color closer than a 50° difference. In a low light setting, you can see red while the steel is below non-magnetic. Your aim should be one or two shades of red beyond non-magnetic.

I don't ever see steel glowing red at all! It starts glowing a dark orange. For me, hardenable heat is VERY BRIGHT orange.

 

[Tumblernotch]

I call dark orange red. But like you I like a bright orange for hardening. Some steels I have to heat almost to a welding heat. Usually just a fairly bright orange.

 

[LRB]

I don't know about exactly how to put this to practical use, but table salt melts at 1474°. a perfect quench temp for carbon steels with more than .80% carbon content, such as 1090, 1095, 52100, and 01, although 01 needs needs soak time at that temp. I guess one could practice reading the color seen on scrap steel by using the salt under controlled light conditions.

 

[mooman76]

Good post. I want to get into flint some day when I have more time to dedicate to it and need to learn all I can.

 

[rustyh]

When you say lay the frizzen in the sand so you can see the face, are you putting the pan cover into the sand or laying the face of the frizzen on the sand, and watching the back of the frizzen to turn straw yellow.
Can you have a frizzen that is too hard? I have a spare one that doesn't spark and doesn't cut with a file. I am going to try to reharden it but wasn't really sure how until this thread started.

 

[rich pierce]

You don't need to reharden if its too hard. Just temper it.

 

[Tumblernotch]

I lay it almost on its side. The heat comes through pretty much from the back side. The pan cover and toe area are a little deeper in the sand and get more heat and actually get a little softer than the frizzen, but not much. You can get a frizzen too hard and it won't spark as good and will wear a flint quicker and actually break one. The sparks you get are tiny pieces of steel and if the frizzen is too hard they're just not gonna peel off. A medium to light straw yellow color works for the cast steels on Siler and L & R locks. From what I've seen the light straw (harder) temper works best with the Siler. (These are frizzens actually cast by Bud Siler). I've only tempered one for a Chambers lock and it seems to be about the same. Some locks seem to like a darker straw temper ( a little softer). An L&R I did recently is this way. I believe a lot depends on lock geometry, or the angle that the flint strikes the frizzen. If you can get the perfect angle with a good flint you can get good sparks at spring temper. But you're going to wear out the frizzen faster.
BTW, as Rich said you don't need to re-harden if you can't cut it with a file. Just draw the temper. If you go too far though, you'll need to re-harden.

 

[rustyh]

Thanks for the info I'll give it a try this weekend.

 

[White Oak]

Just thought I would let you guys know the results of my first and hopefully last frizzen hardening experience. Atleast unless it is my own.
But you know what they say, God looks after idiots and even a blind squirrel occaisionally finds a nut.The gun belongs to a friend of mine who lives about 40 miles away but he mailed the frizzen to me and I back to him. $1.50 each way, cheaper than gas.After I sent it off I dreaded the phone call he promised to let me know if it worked. Wondered if it would spark? Worse yet, would it brake? :idunno: Call came tonight from a very happy guy on the line. The frizzen sparks! Lots of sparks! White sparks! After 35 shots it was still in one piece!The gun that hadn't fired in 10 years was now working.This is not a brag or a gloat guys. Just relief. The only confidence I had was in the numbers I had seen during the process.Wick, I thank you for your input and don't doubt you one bit but upon doing a google search for frizzen hardness I found 56Rc recommended. Our frizzen hardened to 58 to 60 and I do believe it is hardened through.This is also why we did not draw it back. Didn't want to lose what we had. Don't know the terms but the other areas of the frizzen still checked 40Rc which made me believe they were uneffected and not brittle. So hoped it wouldn't brake.
How long will it last? :idunno: I dunno but I would hope until the steel wears too thin as I believe it is hard through.
If I had to do it again I would once again go with the numbers. I would put it in the kiln at the temp that Wick suggested and heat the entire thing. Then draw back the areas that need to be. Going by color takes a lot of experience and I respect anyone who is capable. I am not. What is cherry red? Eveyone sees differently. The heating beyond magnetic would be helpful but for myself I would prefer the Rc scale.
Don't know if I said so earlier but I had some selfish reasons for attempting this. See, he also has a 54 cal Renegade flint lock that he bought incase he was unable to get this gun working. He told me if the frizzen worked he would be willing to sell the TC. He asked tonight if I wanted it. I said absolutely but told him to hang on to it until he was certain that all was well with this gun.
Guys, a whole lot of dumb luck came to play here but I couldn't be happier that it is working.
Thanks again for everyones input! :bow:
Take care,
Ed