Hardening Frizzen face

[leanin chair]

Anyone had any experience hardening a frizzen using casenite?

 

[robinghewitt]

Wipe the face with oil and press it into the casenite to get a good cover, get a bucket of cold water, some tongs if it's pistol sized and clamp it in your vice face up.

Apply heat to get it up to an orange glow, sprinkle on more casenite and cook foe a minute or two.

If big, undo vice and allow it to fall in the water. If small use the tongs and hurry it into the water with a swirl.

If it doesn't pop when it hits the water then it wasn't hot enough, so warm it up and try again.

 

The Squire's advice is excellent - do it his way and you'll have a good result. I like to do them a couple times, minimum - it seems to get the case in deeper.

 

[leanin chair]

Thanx Squire & Daryl. Took 2 trys, but I'm getting sparks now. Also have hairline cracks in the frizen now. Do you think I might have been better quenching in oil instead of water?

 

[robinghewitt]

Oil is even more of a shock than water because the iron can't form an insulating steam jacket around itself.

Surface cracks are not usual :: but they should only be in the hard case and not the soft core so they shouldn't be a problem.

 

Make certain your flint is positioned for best results. At 1/2 cock, the normal position is just touching, or just barley clear of the frizzen - 1 or the other. As soon as it's knapped, it will be clear of the frizzen. When knapping the flint that's in the frizzen, support the bottom surface of the flint with a finger as you knapp (strike)downwards along the cutting edge. The finger underneath helps support the bolster/sear engagement against the shocks of the tapping.
: A sharp flint produces the most sparks. Look to see where the sparks go. Invert the flint to see if that's in improvement. Some locks prefer the bevel up, some bevel down.

 

[musketman]

Traditional Case Hardening is done by packing the soft iron or steel parts in a cast iron box, together with a mixture of charred bone meal, leather scraps or parings from hooves etc. The top is wired in place and sealed with fireclay.

The entire box is then heated in forge or furnace, to a medium red heat for several hours, after which it is removed, the wires clipped and the entire contents dumped into clear cold water.

 

[Zonie]

... Also have hairline cracks in the frizen now. Do you think I might have been better quenching in oil instead of water?

Hopefully the cracks are just surface cracks and don't penetrate very far.

IMO, water quenching cools the material much faster than oil quenching.
Although the water turns to steam rapidly, the water races back onto the steel as soon as the steam bubble moves away from the metal. The cold water then returns to chill the metal again. Water absorbs heat much faster (and gives it off much faster) than oil does. That's the reason most cars use water instead of oil in their radiators to cool their engines.

Oil on the other hand forms a layer which although it may temperarly make smoke tends to cling to the metal and protects it from additional cold oil coming in contact with the metal too rapidly.

One of the problems with adding a case hardening to a frizzen is it is impossible to know what material the frizzen is made from.
Siler for instance uses a thru hardening material which must be oil quenched. Water quenching will crack it.
Before applying Casenit or other carburizing materials, it is wise to just heat the part up until it is bright red/yellow and quench it in oil. If this hardens it to a "file hard" condition, it is a oil hardening steel and must not be water quenched. It also will need to be tempered so it isn't so hard that it breaks when it is used.

Frizzens made from low carbon steel will work best with water quenching and because the material below the case stays ductile, it won't crack. Low carbon steel will not harden below the "case" depth.

If your small cracks are in the thicker area of the frizzen, it is probably ok. If the cracks are in the thin areas like where the screw passes thru the frizzen, they will get worse, leading to possible failure.

If the frizzen cracks are on the sides, right at the "L" where the face meets the underside and if they go thru this thin area, you can keep them from getting worse by grinding them away. You must remove enough material so that you get rid of the full depth of the crack.
Although this sounds like your weakening the area (which you are), by removing all of the crack, you will have stopped a future failure.
Cracks are known as "stress risers". The bottom of the crack is so very small that any stress applied to the part will concentrate at this location. The stress at this point can exceed 300,000 PSI which is well above the tensile strength of any steel. This will cause the crack to grow deeper until the part fails.

The idea of removing material to get rid of the cracks can also be used at the thin area where the frizzen screw is located.

Whether your frizzen is oil hardening steel, or low carbon steel, it would be a good idea to temper it before using it.
This can be done by polishing the surface to a bright appearance and then SLOWLY heating it until it turns a light yellow. You can water quench it from this temperature without harm.

I'm keeping my fingers crossed for you.