Bevel Setting a Wedge

Okudo Wedge 1

Breadknifed Wedge vs Okudo Suita

I've had this heavy grind razor sitting out for while - steel seems good, but it had a pronounced frown. It’s a Christoffersen Wedge, made in Solingen, imported by Christoffersen in Minnesota – probably early 1900s, the grind is heavy, maybe 1/8 hollow.

 I've been thinking about how to approach it - and I decided to bread knife it.

 I didn't have to BK it, I wanted to. This illustration is a basic outline of the blade’s frowing bevel and edge. 

I have two new Okudo Suita that I've been bouncing back/forth with, and I figured a shoot out with a very difficult blade would shed light on a few things. 

 I BK'd the frown out so the new 'edge' started at the apex of the frown, right at the cutting edge.

Doing so left a portion of the existing bevel in place, it ran in both directions, heel/toe, for a decent distance. the new start point for the edge/bevel is shown with the dotted line below. 

 I have Okudo Tomo, but I also wanted to check into using a DMT to slurry them. Normally - I wouldn't do this. They're a bit soft and the last thing I need is a diamond stuck in one or both of them. But - I also have to finish lap both of them so I figured there was no real danger; a stuck particle would get lapped out. So I went for it.

 Using a 325x, 600x, and a 1200x credit-card DMTs on two Okudo suita I counted laps and did my best to keep all other factors as consistent as possible; amount of slurry, stroke type, etc. For each round, the DN was throroughly cleaned and rinsed.

 I checked the bevel's progress as I went along - after each session on each stone I put the 10x loupe to the bevel to gauge the scratch pattern and progress.

 Strange thing - the slurry from the 325 and the 600x DMT left a more pronounced scratch pattern, significantly so, but the slurry from the 1200x DN gave a finer scratch pattern but the odd thing is that this was the most efficient slurry. Yes - the slurry from the 1200x DN cut more steel more quickly than the slurry from the other two.

 How did I determine that the speed was going down with using the coarser DMTs?

Witness marks on the blade allowed me to view the reduction in the size of the existing peice of the original bevel.

Similarly - the slurry from my Okudo Tomo gave a finer scratch pattern than the 1200x DMT, but it reduced the size of the existing bevel at just about the same rate.

 I equate the shrinking of the existing bevel as steel being removed; that bevel had a completely different scratch pattern and angle so it was very easy to map the progress. The area of the bevel I’m referring to is the red section in this next drawing. 

Both Suita returned identical results. They were sold as Okudo, but they're totally different types; one is either Hon or Shiro – possibly Habutae, the other is a typical Renge Suita. Both stones have very similar hardness, but the Habutae is markedly faster and finer.

 I have no real conclusion after this. Logic says that the coarser DMT would generate larger particles; it did that exactly, the scratch pattern told the story there. But it also stands to reason that the larger particles would remove more steel if the time and pressure used were the same, and they were – but that’s not what happened.     

Normally - I won’t use a DMT to slurry anything, and choosing a Suita to set the bevel on a BK’d wedge is too slow and it wastes too much stone. To be honest, I won’t usually buy a frowning blade unless it’s dirt cheap and, generally speaking – I’ll normally choose to hone the frown out before I bread knife it.

So I have a lot of things going on that would not normally occur individually, let alone simultaneously. At the end of the day - I think I learned a lot from this little venture. 

© Keith V Johnson 2014 - 2018