Flintlock Frizzen Hardness

mooncoon

mooncoon

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A question for those who case harden frizzens ; what colour do you draw the hardness to when casing the frizzen on a flintlock ? I normally draw it to medium to dark brown but th sparks tend to be small and sparkly. On quality original locks, the sparks are often dark yellow and relatively large and much more likely to ignite the priming charge. I would think there must be a balance between hard and soft where the frizzen sparks with large yellow sparks and does not wear away too quickly. Too soft and no sparks

cheers mooncoon
 
Not a direct answer to your question, but a properly hardened frizzen should be at RC 60 -62. The precise hardening and tempering temperatures would depend on the composition of the steel. I have no particular expertise in the area, but would likely heat the frizzen to non magnetic, quench in warm oil and temper at 400 degrees F. In my experience, tempering based on color can be pretty iffy, but a light straw should yield something in the ballpark. Medium to dark brown would be around 480 degrees, which would likely result in a softer than optimal frizzen.
 
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Has anyone ever checked the RC rating of a frizzen from an original lock with excellent sparking performance?
Does the exact composition of the frizzen face make a difference? I suspect there is more to it than just hardness.

The frizzen on a high grade English shotgun I have made in 1822 was made with a separate face.
Years ago there was a batch of internal spring military locks sold off. Those sparked like crazy and also had faced frizzens. The sparks hissed and overflowed the pan.

Mild steel must be case hardened to spark. But do the best sparking locks use case hardened frizzens?
I think a lot of modern cast frizzens use 6150 steel.
 
Just went through this with a baker lock from TRS that would not harden - also not a direct reply but:

I think (I don't know) the colour of sparks are determined by the material - you hear anecdotes that a good machinist can tell the type of steel by the colour and length of spark.

The baker lock, I tried to harden it twice, simply wouldn't harden. Finally called TRS & got some interesting info.
"Cherry Red" may be the only Kasenite substitute we have, but apparently it does not work for frizzens.... I wound up sending the frizzen back & Jesse said he would send me some stuff to add to the cherry red to make it work (still waiting)

They are also recommending annealing the tail only ... which seems logical.

My question (that I have asked a bunch of people a bunch of times) is "how many kicks at the can do we get?" Harden it once and that's it - you will need to case harden thereafter or do we get a variable number of tries depending on the carbon content? Are we burning carbon off each time we try to heat the part?

You see knife makers on that knife making show that I can't remember the title of right now taking 2 and 3 tries at hardening a knife ... THEN the judges keep on about "he's gonna burn that steel ... too hot... too hot!!" does that mean the carbon is being burnt off (is that even a thing?)
 
The steel in Chambers and, I am quite certain, Kibler frizzens is 1095. The maximum amount of carbon in steel is 2%. Ten Ninety Five has .95% carbon. Sixty one fifty has .48% to .53% carbon. As I understand it, the friction heat ignites the carbon particles in the steel, so boosting the carbon content at the surface (case hardening) should increase performance.
 
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my understanding is that carbon penetrates the steel by .001 inches per minute of being at red hot. Over time it wears away and has to be redone in addition to the frizzen face being ground to a smooth curve. After many shots even a high carbon frizzen will develop a couple of ridges or ripples that slow the flint down and reduce sparking. I think role of carbon is to harden the steel enough that scraping tiny bits off creates heat and the harden the material, the higher the temperature but also the smaller and brighter the spark and the faster it cools off before reaching the priming powder. It occurred to me after posting that I could draw the temper in molten lead using a high temperature thermometer to tell exactly what temperature I was drawing to. Alloy lead melts around 550 F so I will try that temperature and see what happens.
In reply to Tiriaq, I have seen some original frizzens that have been shoed but also original frizzens that were not shoed and through large yellow sparks
I continue to marvel at how small differences in design make the difference between a good well sparking lock and one that works poorly and wonder how much experimenting with small changes in design it took, back in the 1600s to come up with a good lock

cheers mooncoon
 
Look forward to hearing the results, but believe drawing the temper at 550 F is too high, and will result in a too-soft frizzen.
Wouldn't be the first time I was mistaken:rolleyes:
 
I tried drawing the temper with molten lead at about 550 F; puzzling thing is that the portion that was near the surface oxidized to blue while the body of the frizzen face was brown. Either way, the frizzen didn't spark . Since I already had the lead molten, I decided to preload the main spring more (I draw the temper to between 720 and 740 F) It would seem I preloaded too much and I have almost finished its replacement :>( The lock is a cheap one further compounded by having the internals from spare parts of poor design, so I am also in the last stages of making a new tumbler, which I should have done in the beginning. At this point I am holding my breath that the lock will spark.
Worth mentioning that I filed the square section of the tumbler by holding it in a 4 jaw chuck on the lathe and using the jaws to guage when I was filing a square; don't know why I never thought of it long ago.
In reply to sean69, I think a machinist might be able to guess the identity of the steel by the sparks if they worked with only a few grades of steel but doubt the method would work on a piece of scrap ; the sparks would show only that it was high, medium of low carbon.
also relative to Tiriaq and shoeing a frizzen face, garden shovel blades would probably be a good source of material because they seem to be a high carbon steel
Anyway, I will report back in a day or two when hopefully the lock is out of my hair

cheers mooncoon
 
You should be drawing the temper at 400 degrees to achieve RC 60 -62. Your kitchen oven is likely a good place to do the job. I would also pack (case) harden the frizzen by packing it in charcoal in a confined (not completely airtight) container and heating to cherry red for an hour or two. Carbon penetration is generally assumed to be .003" to .005" per hour.
 
In reply to sean69, I think a machinist might be able to guess the identity of the steel by the sparks if they worked with only a few grades of steel but doubt the method would work on a piece of scrap ; the sparks would show only that it was high, medium of low carbon.
Click to expand...

So I got interested (OCD actually) and went to track down the origins of the anecdote .... turns out it is not an anecdote at all - you can determine at least the family (if not grade) of steel using a "spark test" https://en.wikipedia.org/wiki/Spark_testing

a particularly interesting wiki!!

600px-Spark_testing_2.png
 
The saga and frustration continues; finished the spring and tumbler, decided to case the frizzen some more although the first casing should have been enough. No sparks or only an occasional one; guess I will knap the flint and preload the spring a bit more. Frustrating and baffling because I have cased a number of frizzens over the years and they have always sparked although often after the first 6 or 7 strikes then they would spark regularly
Some original locks spark like examples G and H above with big long lasting orange sparks while most modern locks spark more like example C and D

cheers mooncoon
 
I remember one frizzen that just would not spark no matter how it was heat treated. Ended up sweating on a shoe - then the lock worked just fine.
 
Success at last; I tried striking the detached frizzen on a flint spall to see if it would spark similar to using a flint and steel to start a fire; no luck so I thought I would start over again and heat red hot, quench then draw to the very beginning of brown, which I expected to be too hard; it sparked a little striking free hand but when I put it in the lock, it sparks quite well although the sparks are bright and sparkly unlike the large orange sparks I would have preferred. Makes me think I have been drawing frizzens a bit too much in the past

cheers mooncoon
 
Re: spark tests

Setting aside the more exotic materials, it’s the number of bursting sparks that gives you an indication of the carbon content of steel. However, this is not a reliable test with all grinding compounds. Aluminum oxide gets used but I was taught to only use carbide wheels.
 
Sparks of my original French Maréchaussée 1802 pistol, whose frizzen has been hardened by Bernard Riendeau of Noyan.




2024-06-23 Pistolet An IX.jpg
 
Sparks of my original An XIII pistol (1804), original hardening.
These pistols had no aiming aids and were known for shooting very high.
Notice the laser like bullet track that hits the wooden wall.


2023-08-13 (2).jpg
 
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