Timber Framers Guild Forums Tools Tool Forum tapping out chisel edges

I've now got my 2 chisels straighened out. I had to use a combination of hydraulic press (and being careful) and peening. Then when I was satisfied when holding up my combination square straight edge, I started lapping them on plate glass with wet/dry paper starting at 180 grit. It takes a long time to take a couple thousanths off. I got my 1.5 inch chisel where I want it, but am still working on my 2 inch chisel. I'm hoping that with normal use and care, my chisels won't deflect or lose the straighness that I've now got them to. I would think that mallet blows should not be enough to do this. There should be enough spring back in the chisel as well.

I know I shouldn't say this, but perfection in sharpening chisel edges, whatever philosophy you adhere to, is basically a waste of time, propounded by non-producers, in the commercial sense.

If, by whatever means, I get a good edge, ie shaves off my forearm, that's good enough for me: for a minute or two:ie before the chisel gets hammered in whatever situation I am putting it to, gapped, or whatever.

Today I gapped a Japanese mortise chisel I was given 10 yrs ago on a nail inside a 200 yr old door: I reasoned, that is good service. I'll regrind it on my Tormek as quick as I can, it reduces it a bit, but it will probably last me out.

Planes, maybe...but chisels:no.

had to take a pic of this, one of my favorite plane blades(a stanley sweetheart), fallen victim to a hemlock knot....

"400 is in the tempering range"

This is true, and the reason why I advocate using that temperature. It will be the minimum temp that chisels will be tempered at, and that would be if they are a medium carbon steel. Higher carbon steels need to be tempered at an elevated temp in my experience. Heating to that temperature will not open any can of worms with the steel, but you might not want the handle on it when you do it.

" if you are going to go that far, you could just reforge the end and retemper"

Partly true, and reforging would indeed be way too much work. Again, the temperatures that I mentioned are not sufficient to remove the temper from the chisel,(BTW, what Mr. Davidson is doing up there is forging, just not at a high temp) Typical ranges for hot forging carbon and low alloy steels is in the range of 1600 to 2300 degreesF, a far cry from what I had mentioned.

Believe it or not, a standard practice in industry to relieve grinding stresses, ect, is to bring the part up to the final tempering temp and hold for an hour or three.

Brad -180 grit sounds too fine to me, I often use 40 and 60 to take down a bad back.

I hear what you are saying about a coarser grit. The 180 will definitely take longer, but I'm almost there now. I have a chip (was a defect in the chisel) in the corner of my 1.5 inch chisel and about .125 needs to be ground off the chisel to get past it and back to a full square edge. Today I am going to set up on the surface grinder here at work (with coolant) and it will probably take a couple hours to grind it down. I'm setting up at 25 degrees.
One thing I was taught at my introductory timber framing class...
"Perfection and Grace puts a smile on your face". Corny but true to a craftman.