Hardening with Kasenit - advice?

[MRA]

Hi folks

I have just made a jaw for a small 4-jaw lathe chuck which was missing one. I'm rather pleased with myself - it is the most accurate bit of milling I have done at home, on a very home-made machine.

But - it is soft - mild steel. I'd like to harden it, and I have some Kasenit which I have used once before - but not where dimensional accuracy is important. Does anyone have much experience with this stuff? I'd be interested if anyone can tell me if my probable approach - make a sealed container, put the part in with the powder, and leave it in the woodstove all night - is likely to result in distortion or not. I suppose if it distorts a bit I can try to dress it up with a Dremel, but it would be nice to keep this to a minimum.

I'd add a photo of the part, but I don't have a camera at the moment. It's a small part - the chuck is a 3.1/4" Burnerd; an older one of these

https://www.ebay.co.uk/itm/334619741884
cheers
Mark

 

[Jasonb]

I'm not sure case hardening would do a lot, actual jaws are fully hardened not just the surface that you get with case hardening.

But when I use the stuff I heat the part to red heat and then coat it with the powder, heat again and quench. You can do the heat/powder cycle a couple of times to get a slightly deeper skin but it will still have a mild steel core.

 

[trlvn]

There was a Youtube video recently where the guy tried to work out a home-workshop process for case hardening. Might give you some pointers:



Craig

 

[MRA]

There was a Youtube video recently where the guy tried to work out a home-workshop process for case hardening. Might give you some pointers:



Craig

Thanks Craig, that's just what I needed. It was good to see some discussion of home-made carburizing materials - I have some branded stuff, but it will be fun to try something made at home too. I liked his packing containers sealed with clay too - lots of good ideas there.

 

[Steamchick]

Interesting.
Some bits of my limited knowledge:
As a lad I had a good hot wood fire going, with thick bed of charcoal at the bottom and through air supply, and my boss told me to drop some machined parts into the red-hot charcoal to give the steel some case-hardening.
He also had some old shoes he had collected, so another time he told me to wrap the parts tightly with the leather from the shoes and secure with iron wire, then drop those into my fire, which wasn't so hot that day, just poor soft-wood.
When there was no fire available, we used paraffin blow-lamps and Casenite, or sugar if we had no Kasenite! (We had 2 brands, with alternative spelling).
Another time I blunted some HS drills on some mild steel brackets that I had Sif-bronze brazed to some exhaust pipes using a carbon-arc torch. Once through the case-hard surface the mild steel was Normal beneath.
My school teacher told us about medieval blacksmiths who fed donkeys lots of turnips, but no water to drink, then collected their pee for quenching hot iron, to harden the surface. The modern method uses nitriding powder (High N Fertiliser can be used) or ammonia flames in a furnace for nitriding. (e.g. the Nitrided steel Piston rings in your car's engine).
Japanese sword makers clad Samurai swords in clay, of varying thickness, so the steel is hardened and tempered differently by the different heating beneath varying thickness of clay. Hard at the cutting edge, but softer beneath through to the core and back of the blade to resist cracking.
Romans with wrought steel bladed swords (designed for stabbing) often snapped when hit with a Phoenician bronze sword, because the bronze sword was more fatigue and crack resistant, but the edge dented when hit with a steel sharp blade.
K2

 

[Gordon]

I thought that Kasenite was now illegal. Is it still available? Pretty dangerous stuff in any case. Emitted cyanide gas if I remember correctly.

 

[methuselah1]

I thought that Kasenite was now illegal. Is it still available? Pretty dangerous stuff in any case. Emitted cyanide gas if I remember correctly.

Well, I don't know about cyanide gas (there are many different CN compounds- not all are deadly) but the fumes are certainly pretty acrid (ammonia) so it's best used with a window open.

The difficulty in the UK was that our Kasenit company went bust; the American branch didn't, but it led to a supply crisis around 1995. These days, any gunsmithing concern will supply a similar compound, decanted into small quantities. Peter Dyson springs to mind- there will be other suppliers.

-Andrew UK

 

[MRA]

Here's a pic, in case anyone is interested. The Burnerd part is on the left, and my approximation on the right. It appears to work; as to how hard...well, harder than it was!

 

[HMEL]

Hi folks

I have just made a jaw for a small 4-jaw lathe chuck which was missing one. I'm rather pleased with myself - it is the most accurate bit of milling I have done at home, on a very home-made machine.

But - it is soft - mild steel. I'd like to harden it, and I have some Kasenit which I have used once before - but not where dimensional accuracy is important. Does anyone have much experience with this stuff? I'd be interested if anyone can tell me if my probable approach - make a sealed container, put the part in with the powder, and leave it in the woodstove all night - is likely to result in distortion or not. I suppose if it distorts a bit I can try to dress it up with a Dremel, but it would be nice to keep this to a minimum.

I'd add a photo of the part, but I don't have a camera at the moment. It's a small part - the chuck is a 3.1/4" Burnerd; an older one of these

https://www.ebay.co.uk/itm/334619741884
cheers
Mark

Go to u tube tubalcain #717 he has a two part video on this stuff.
Trick is control of the temperature and time element involved tubalcain ie mrpete actually uses kasinite.

 

[a41capt]

Well, I don't know about cyanide gas (there are many different CN compounds- not all are deadly) but the fumes are certainly pretty acrid (ammonia) so it's best used with a window open.

The difficulty in the UK was that our Kasenit company went bust; the American branch didn't, but it led to a supply crisis around 1995. These days, any gunsmithing concern will supply a similar compound, decanted into small quantities. Peter Dyson springs to mind- there will be other suppliers.

-Andrew UK

Actually, cyanide bound to the various salts are indeed stable as you’ve stated, but once their pH is reduced, they liberate cyanide as a gas that is indeed very toxic. It has a high affinity for the iron bound in your mitochondria, effectively shutting down cellular energy production and killing the exposed organism unless an antidote, usually a nitrite/nitrate preparation is introduced.

This nitrite/nitrate converts some of the iron in hemoglobin (formation of partial methemoglobinemia) thereby creating a higher outside iron concentration and changing the osmotic gradient. This draws the cyanide from the cellular mitochondria and reversing the poison, and with the additional application of sodium thiosulfate, allows excretion through the kidneys, and well, I guess we all know where that ends up.

This is a much abbreviated explanation from my toxicology training, but explains how a cyanide bearing compound becomes deadly.

Now, Hydrocyanic Acid? Well, that’s a horse of a different color since it’s already a liquified gas under pressure!

John W