Replies

1. 
   vonmagnuson | Aug 26, 2010 12:13pm | #1

   Thanks for posting that link.  Great how-to. 

2. 
   EdHarrison | Sep 19, 2010 03:28pm | #2

   Follow-up Question

   Derek, I'd like to resurrect this thread and ask a follow-up. I'm getting ready to heat treat some chisels this week with the goal of following the procedure listed in your link, along with the comments by Ron Hock. They are 1980's Stanley butt chisels in some wide sizes that I need for letter carving - one of them is 2 inches (50mm) wide. I'm hoping that they are O-1 and the formula will work and I will end up, after heat treating, quenching and tempering, with RC 60-62.

   The question is this: If they already have a bevel and an edge (they are sharpened, in other words), do you grind some of that off before you heat treat? If you leave the sharp edge that's already there, do you assume that it will be unusable until you grind it back somewhat after you are done with everything? I am confused about ruining an edge by blueing it, versus heat treating it.

   The photo attached shows the way that I do my chisel handles. These two didn't need to be heat treated because they are already the way I like them and they sharpen and hold an edge predictably and the way I like them - the short one is a Millers Falls and the long one is an 70's vintage Sandvik (an underrated chisel, imo).  The plastic handles get cut off and replaced with wooden ones - I only used the ebony because I had some scraps in my shop for over ten years - reading about the ebony trade in Madagascar, I would not think it socially responsible to buy it nowadays. I have about nine or ten more chisels to do, some will be heat treated, some not.

   Thanks, EH

   
1. 
   derekcohen | Sep 20, 2010 10:49am | #3

   Hi Ed

   Six of one and half a dozen of the other ...

   If I leave the bevel in place, I will end up grinding it back a little as the edge is likely to be a little brittle. And if I grind the edge flat before heat treating to avoid the problem associated with thin steel, then I still have to grind a new bevel.

   "Blueing" an edge is generally the term given to the involuntary overheating of a blade on a grinder. This will soften the steel. "Heat treating" involves deliberate heating to either harden or temper (soften) the steel. If you have an edge that folds it is too soft and you will want to first (over) harden the steel, and follow this by softening it to a desired level of hardness (tempering). If the steel chips it is likely to be overhard and it will need to be softened. Tempering is best done in an oven, contrary to my article, which was simply a demonstration of how the process can be done quickly.

   Those are really nice handles. I like the ebony one particularly. And I'm not surprised by your comment about Sandvik - after all they are the descendents of Berg.

   Regards from Perth

   Derek