Charlotte Posted June 4, 2009 Share Posted June 4, 2009 (edited) F-N a few thousandths of hardening for "cherry red " is often enough to last for a long time on a polished shaft that is well lubricated. I suggest you try an experiment. make two identical leaf veining dies, harden one, and forge equal numbers of leaves into them. After one hundred leaves; which one is producing the best leaf? Point being: A few is a relative term and case hardening is a technique for tools that get serious use. I have cased fullers because I like leaving a good finish and fit. Many people case harden A36 tools they make for Smithin Magician type dies. 4140, or 5160 is the choice alloy. Finding it and buying in 3/4"x2" gets to be a little expensive for most folks. 4140 blank dies from Blacksmiths Journal are 12 bucks and mild steel are 5 bucks. Finished dies run around 60 bucks. Personally if I take the time to make a die then I'm going to spend a few minutes make sure that it lasts as long as possible. Edited June 4, 2009 by Charlotte spelling Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted June 4, 2009 Share Posted June 4, 2009 FN---it was a sort of gedanken experiment to get folks to think about situations where it would be a good idea to case harden. Actually we smiths would be in Hog Heaven if folks used the *best* alloys for stuff instead of the cheapest that will do; we'd save a lot of money on high alloy steels mining the scrap stream! Quote Link to comment Share on other sites More sharing options...
evfreek Posted June 4, 2009 Share Posted June 4, 2009 Hi fisher norris. Yes, a few thousandths of an inch is not much. With a good pack case, you can get a bit more, maybe up to 50 thousandths. Have you ever tried to hob a gear in a mill? Some gears will gnash if they are more than a few thousandths off. So the conventional Internet wisdom about a few thousandths of case hardening being useless since it wears off rapidly to soft metal is pretty much true, but for this practical matter, it is wrong. It is exactly those few thousandths of an inch that are important. One question I have about "Cherry Heat": what makes it different from Kasenit? I saw a demo of cherry heat. When the piece was quenched rapidly, there was a pronounced "crack" noise. The demonstrator said that this was due to the solidified shell of the case shattering due to some sort of volume change, possibly martensite transition expansion. One of the fellows in the audience did a demo later with kasenit, and did the exactly same thing, even making the point to the audience that you had to hear the "crack" else it was no good. He even did the quenching motion correctly, swinging the bar in an arc so that it gets in the water quickly. But, no "crack". After the third time, he gave up and tested the piece with a file. Full hard!!! Everybody was scratching their head until someone realized that the first demonstrator used cherry heat and the current demonstrator used kasenit. That finished tool looked hard to me. I wouldn't have minded using it. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted June 5, 2009 Share Posted June 5, 2009 The two are different formulations and Kasenit produces more toxic compounds on heating. Used to be that kasenit was substantually cheaper and more widely sold but since I still have my first can I don't know what the current price is. I've never used "Cherry Heat" I was aquainted with a proprieter run machine shop that use nothing but Chery Heat. My personal intrest in the web site is that Wilcarbon Pack case hardener listed by the same people. I bought 10 feet of 3/4x2" A36 that I'm going to turn into Smithing Magician dies. When I get them finished to spec I'll pack case harden so about 1/64 inch. These will be finishing dies. Quote Link to comment Share on other sites More sharing options...
fisher_norris Posted June 5, 2009 Share Posted June 5, 2009 it seems that case hardening is very useful and but as all i have is 5160 and coil springs i wont be needing it soon! thank mechanics and nice repair shop owners and friends who are friends with the nice repair shop owners! Quote Link to comment Share on other sites More sharing options...
Charlotte Posted June 5, 2009 Share Posted June 5, 2009 Congratulations on your good fortune! Quote Link to comment Share on other sites More sharing options...
MattBower Posted June 8, 2009 Share Posted June 8, 2009 The main active ingredient of Kasenit appears to be sodium ferrocyanide. Interesting stuff. It's not as scary as it sounds; it's actually a food additive! But it does evolve hydrogen cyanide gas when it decomposes (which happens at about 800 degrees F). Quote Link to comment Share on other sites More sharing options...
short swing Posted June 28, 2009 Share Posted June 28, 2009 Thanks alot you guys. When you realize that you know everything, and someone teaches you something. Its like learning to speak agian. Quote Link to comment Share on other sites More sharing options...
rockstar.esq Posted June 30, 2009 Share Posted June 30, 2009 Just out of curiosity, is there any enhanced corrosion resistance using any of the proscribed methods? I recall hearing about lever action rifle receivers getting bone charcoal case hardened which leaves a mottled and colorful finish not unlike a bluing. Not really a super strong finish but certainly better than bare steel. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted June 30, 2009 Share Posted June 30, 2009 Rockstar, The finish you are talking about is called "color case hardening" . It is a very thin oxide film that appears when a superficialy case hardend steel item is rapidly quenched in high oxygented water. To appear all the steel must have a very smooth 1500 grit or better finish. In general the more highly polished, and lower in carbon content, plain carbon steels are the less prone to rust. Color case hardening is done to reduce wear and because it is pretty. Any protective effect is a result of polish and oil coating over the oxide. Quote Link to comment Share on other sites More sharing options...
MattBower Posted June 30, 2009 Share Posted June 30, 2009 Boy, it sure is pretty! Too bad it's too fragile for a lot of the applications that interest me. Quote Link to comment Share on other sites More sharing options...
Pannoowau Posted December 11, 2009 Share Posted December 11, 2009 thanks for the posts.... really its look good... keep on posting guy.... __________________Compound Interest Formula Quote Link to comment Share on other sites More sharing options...
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