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I was wondering if anyone knows how to heat treat or temper chisels. I bought these beatufiul Bubinga handled chisels, paid extra for the sharpening service. 3 or 4 whacks with the mallet into my Bubinga condor tails and it was dull. Very disappointed, any way to harden them?
Check threads in the neander forum. Those guys are constantly doing this sort of stuff.
Bill, the problem is knowing what tool steel they are made of because the requirements for heat treating vary greatly. If they were mine and I had decided they were useless as is I would remove the handles, heat the chisels to bright orange or cherry then put them in a 5 gallon can of vermiculite to anneal until they cool. Then reheat to orange and quench in oil to harden. Then very carefully heat the shank above the cutting edge and watch the colors run towards the edge and quench in oil when the edge is straw colored.
All the while knowing this may not be the right procedure for the tool steel the chisels are made of and they may still be useless when you are done not to mention the toxic smoke from the quench oil and the possibility of burning yourself if you aren't setup to do this kind of stuff. You might find a local hobby blacksmith that could do this for you but you can probably see this may all be more trouble and expense than it's worth.
I have made very good chisels out of coil spring doing the above but I have a forge and everything else needed. I don't make tools out of scrapyard (unknown) steel anymore. It just isn't worth the trouble and the danger of a tool spalling off a piece of steel when you are using it because it was incorrectly heat treated.
+1 on what Chris is saying. They are probably oil hardening steel but there is also water and air hardening steels. Oil is the most commonly used. I hope it is a quality steel that will harden properly. You really only need to get the first inch hot for the quench. When you do quench them move them around in the oil in a stirring motion because the oil boils at first contact and by stirring you get a faster quench which is important in consistent through hardening. Where some welding gloves if you have them because you will get a flame up at first contact. Disappointing that they aren't what they should be. Good luck.
What chisels are we talking about here?
As Joe said...what kind of chisels are they? There are chisels made for wacking, and chisels not made for that. My first though is a chisel made with Bubinga handles might be a nicer paring chisel vs a typical bench chisel???
JeffD
I have found this utube link extremely valuable if you are tempering steel,you still need special tools/anvil/heat source etc.
http://www.youtube.com/watch?feature...&v=qQ9eysoFjsk
Im out of town right now but when I get back I'll post the info & pics. I got them from Woodcraft.
Don't waste any more time on a bad product. Send them backQuote:
Originally Posted by Bill Wyko
New chisels will often be a little soft at the end and will take a few sharpenings or even a little grinding back to the point where they're hard enough to function well. The sharpening angle could also be problematic. If it is too shallow, they will not hold up when chopping in a hard exotic wood like bubinga. You could try putting a microbevel on them and see if they hold up better, but if you got them new from Woodcraft and aren't satisfied, I would just take them back. I certainly wouldn't waste my time heat treating them.
FWIW, my experience with WC's sharpening service has been that it isn't worth the money. The blades I've seen that had the sharpening service applied to certainly would cut, especially compared to a blade that had nothing done to it (assuming we're not comparing to how LV ships their blades out); but were far from what I'd consider sharp. They also did nothing to the back of the blade. I certainly wouldn't expect what I saw to hold up to mallet blows. I would be tempted to actually sharpen the blade to proper sharp before use and try again. Certainly would try that, and maybe even hitting the grinder for a bit (on occasion a new chisel gets a little fragile at the edge and needs to be ground back before hitting good steel) before attempting to re-temper the steel or sending it back.
Perhaps you've done these things, you don't mention.
Have you dulled all the chisel yet? I'd be tempted to try something like shaving end grain on a soft wood, or the arm-hair or paper slicing tests to see if what they shipped you was actually sharp.
FWIW, I believe the Woodcraft chisels are CRV steel if I remember correctly (edit - just checked, if you're talking the woodriver chisels, yep, CRV) - with no background in metal working I have no idea if that changes the re-tempering process, but it gives someone with more knowledge a starting point.
All the above advice has been good. You can attempt to tell what kind of tool steel they are made of by googling a spark test chart. Different tool steels make different looking sparks when being ground on a bench grinder. If you can determine whether the steel is oil hardening or water hardening,you will know what to quench it in at least. As said,CRV steel is likely oil hardening.
A problem that hasn't been mentioned is that,since the chisels already have the bevels ground on them,the front and back sides of the chisel will have different surface areas. The chisels will likely warp when you quench them. They may also cup across their width. That certainly happens with beveled plane irons. I have warped a few over my learning curve years!
Another problem is,you still cannot tell if the steel has a decent amount of carbon in it. Even if you get them harder,the chisels may not hold an edge very long. The Woodcraft chisels are from China. Somewhere I saw what the carbon content of Wood River plane irons was. I wasn't impressed with their carbon content.
If you can return them,it would be the best resolution since you may ruin them trying to fix them. If they look like you have been grinding their bevels,the store may not take them back,unless they have a liberal return policy. I think Wood Craft would take them back.
If I were you, I would take them back. That being said, any chisel you plan on using on Bubinga needs to have a fairly steep bevel angle(I would start at 30deg. for any chopping). It can certainly be applied as a micro-bevel. That should enhance the edge retension by quite a bit. And make sure the back is flat.
I agree with the others who think you should seek remedy with Woodcraft first. That, after trying a steeper bevel angle or two. I didn't see mention of a brand but if the steel is not "up to it" you won't improve them by re-heat treating them. Or the steel may be an alloy that isn't easily hardened by home-shop methods. In any case, once you try, I doubt WC will let you return them. But if you must, please read this for more info. Remember please to Always Think Safety (Hot-oil! Red-hot steel! Smoke! Fire!) Let us know how they turn out. Good luck.Quote:
Originally Posted by Bill Wyko