Strategy For Chisel Backs
Posted: Fri Aug 25, 2017 6:02 pm
Hi all, first post here. Hoping someone out there has an idea for working these chisel backs. I found this set on ebay about a week ago. I have been casually looking for a 10 piece set with the kaku-uchi shape, so when these revealed themselves for a couple hundred bucks, I figured I did not have much to lose and clicked buy.
They arrived this morning (fast shipping!) and here is how they look with the lacquer off and a quick pass on the lapping plate to see what kind of shape the bevels were in ( I think "convex" would be the the appropriate descriptor).
And here is a shot of the stamp. Some of the handles still had their sticker, which read "Narumiya Sato"
So far so good. The superficial rust, stains on the handles, and rounded bevels were all to be expected on this cheap used set. I went to work lapping the backs so that I could get these bad boys sharpened up.
As I draw the first chisel across the stone I feel a disturbing rocking and feel a corner dig in (keep in mind the ura looks brand new). I get confused and see if there is a chunk of dirt or something on the stone that is causing the chisel to rock. No dice, stone looks clean, and back of the chisel looks like it just came from the smith's shop. So I reference the back of the chisel on my DMT plate (flattest thing I own) and the chisel is rocking back and forth like crazy. There is a clear "high axis" from the back left to the front right corner. Below are two pictures with me pressing on the respective "low spots" with a .020 feeler gauge underneath the resulting gap.
I think maybe this a just a bad apple, start checking the others it the set -- and they almost all have the same issue with the exception of a few of the smaller sizes.
So where to go from here? Should I rub these against a lapping plate for the rest of my life? I am sure I could eventually get them flat, it would take some time and create a very asymmetrical wear pattern on the ura.
Should I just focus on creating a flat behind the cutting edge? I would be able to get the chisels sharp, but couldn't use the chisel back as a reference when paring.
Can I beat these with a hammer a little bit to try in move the back into a single flat plane? Like an aggressive version of tapping out?
Any suggestions appreciated.
- Jack
They arrived this morning (fast shipping!) and here is how they look with the lacquer off and a quick pass on the lapping plate to see what kind of shape the bevels were in ( I think "convex" would be the the appropriate descriptor).
And here is a shot of the stamp. Some of the handles still had their sticker, which read "Narumiya Sato"
So far so good. The superficial rust, stains on the handles, and rounded bevels were all to be expected on this cheap used set. I went to work lapping the backs so that I could get these bad boys sharpened up.
As I draw the first chisel across the stone I feel a disturbing rocking and feel a corner dig in (keep in mind the ura looks brand new). I get confused and see if there is a chunk of dirt or something on the stone that is causing the chisel to rock. No dice, stone looks clean, and back of the chisel looks like it just came from the smith's shop. So I reference the back of the chisel on my DMT plate (flattest thing I own) and the chisel is rocking back and forth like crazy. There is a clear "high axis" from the back left to the front right corner. Below are two pictures with me pressing on the respective "low spots" with a .020 feeler gauge underneath the resulting gap.
I think maybe this a just a bad apple, start checking the others it the set -- and they almost all have the same issue with the exception of a few of the smaller sizes.
So where to go from here? Should I rub these against a lapping plate for the rest of my life? I am sure I could eventually get them flat, it would take some time and create a very asymmetrical wear pattern on the ura.
Should I just focus on creating a flat behind the cutting edge? I would be able to get the chisels sharp, but couldn't use the chisel back as a reference when paring.
Can I beat these with a hammer a little bit to try in move the back into a single flat plane? Like an aggressive version of tapping out?
Any suggestions appreciated.
- Jack