I have always struggled with getting my chisel backs flat. In the past I had been able to get all but the last couple of millimeters flat (the part that needs to be flat)
A little history first. I took a Rob Cosman class up in Calgary probably about 10 years ago. It was a good class, but Rob's procedures can be a bit on the prescriptive side. In the class he had us start the back flattening at our coarsest stone. If you have shaky technique you can actually make a whole heck of a lot more work for yourself (I know I did on a brand new set of LN chisels). I realized later (much later) to start with the finest stone and see what you are dealing with, which I felt was a great improvement and was a little impressed with myself until I watched Deneb Pulchaski suggest the exact same thing in a LN video from quite a number of years ago.
During this quarantine, I figured it was time to get all my chisels up to snuff including a set of Hirschs I have been avoiding dealing with since my small set of LN chisels was such a pain to get flat. (side note: a single edged razor blade was the easiest way remove the lacquer coating on these) So I ran through the process, all the way up to a 16000 Shapton GlassStone. I still had issues with the very tip. I kept backing off, going to coarser grits, even getting down to my 140 Atoma diamond plate. Still no dice. After doing a hack job on most of the set, I realized it must be my technique (not that that was much a surprise) My technique was to hold the tip flat on the stone with one hand and move the chisel with the other, holding on to the part off the stone. I realized that I must be rocking the blade by pushing from further back on the chisel.
Now the insight
Looking around to observe other techniques, I saw Derek's webpage https://www.inthewoodshop.com/Woodwo...%20Blades.html (from 2007 no less) on lapping the backs of blades, where he has a plane blade held by a magnetic base to focus all the forces on the front end of the blade. I realized my issue was due to pushing the chisel from a distance away from the leading edge I must have been rocking it. Not having a magnet available, I thought I could use a stick on wire clip (little nylon clips with peel and stick adhesive on the back) to put a handle on the tip of the chisel to be able to manipulate it on the stones. I couldn't find where my stash of those clips areThen I realized I could use tape and put a little tab on the end of the chisel. Basically putting a loop in the tape (make it like an upside down T)
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So with the tape tab the only place I was touching the chisel (handle was free floating off the edge of the stone) I worked my way from 1200 Atoma, 4000 Shapton GlassStone, 8000 Shapton GlassStone, 16000 Shapton GlassStone. I did have to spend a bit of time on the Atoma to erase my prior sins
Quite a bit less frustrating than my prior "technique" (if you could call it that). I do like the Atoma plates and wished that they would go to finer grit. I guess DMT has an 8000 diamond, might try that.
I'm happy to have figured out a method that I can manage. And thanks to Derek for showing the magnetic base as a handle, which gave me the insight to how I was screwing things up
John
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Originally Posted by John Stankus
