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sharpening... the never ending questions

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sharpening... the never ending questions

#1

sharpening... the never ending questions

Jonathan Ronnow, Sweden

>I was searching the archives for people who sharpen japanese tools with oilstones, by hollow-grinding and the using the hollow to index the tool against the stone. I found lotsa other posts, some rather amusing and well worth reading.

Preferences vary and some people love their sharpening systems and will fight for them. Well I for one love microabrasives, I can get my tools as sharp as they can be, and probably too sharp for my woodworking skills. Im not saying this to brag, but rather to give a background information.

So. I have the veritas guide which I use with the microabrasives. Excellent control, fast honing and all of that. But then came along a coarse/fine india stone, and the wish for a translucent arkansa or perhaps a fine ceramic stone. Why? Some time my blades will be too short to clamp in the guide, and setting up the glass plates with the abrasives and guide and things out in the field is sometimes a bit of a hassle. So, two slow-wearing oilstones and a strop seems to be a nice alternative, and a bit easier to haul around. And yes I can admit that the article at the museum store is inspiring...

Anyways. How will the oilstone road work together with my japanese chisels? Various written advices say that the hard steel in them might fracture if presented to a hard abrasive, and that hollow grinding might weaken them.

I understand that I might get less penetration if I raise the bevel angle to compensate for weakness, but thats a tradeoff Im accepting. After all Im not in such a hurry...

Bob Smalser, you show oilstone honing in your latest tutorial, and also own japanese mortising chisels. Do you hollow grind them?

Jr

Re: sharpening... the never ending questions

#2

Re: sharpening... the never ending questions

Wiley Horne--Glendora CA

>Hi Jonathan,

I think you're on the right track. I am a recent convert to hollow-grinding (thanks Bill Tindall + C&W) and here's why: I find that getting to a primary burr is the step that takes time, not honing to a final edge. With a hollow- ground blade, there is very little work to get to a primary burr.

As to the Japanese blades, I haven't had enough time to evaluate the results of hollow grinding. However, the argument against hollow grinding is that it is cutting away the support for the hard steel. But yesterday, I hollow ground a 1/2" Japanese mortising chisel. And what happens is that the hollow is long and shallow, so that very little backing is removed. And this is using a 6" grinder.

I am very stoked about hollow grinding, and am wondering why it took me 10 years to get around to it. Once the blade is hollow ground, you can get to a primary burr almost instantly, and it is easy to hold onto the desired bevel angle. That is, I don't have the tendency to begin creating secondary bevels when freehand sharpening.

So even though I am a beginner at hollow grinding myself, I strongly encourage you to give it a try, including with the Japanese blades.

The big issue for me was to not burn or 'blue' the edge, or even get close to bluing it. Bill Tindall's advice here worked out perfectly: Make numerous light passes, side to side, each time removing very little metal. I took a long time on that mortise chisel blade, but it barely got warm to the touch. This was using an 80grit vitrified ruby wheel from Japan Woodworker. I handheld the blade, and used the toolrest which comes with the Baldor grinder as a rough guide. In other words, you don't need to jig the blade IME.

Once you've hollow ground the blade, it doesn't take much metal removal to get it sharp, so I would think the oil stones would work fine. That's what Bill and Larry use at C&W. I like diamond myself. But it really doesn't matter what you use IMO, because most of the work has already been done by the hollow grinding.

Wiley

Re: sharpening... the never ending questions

#3

Re: sharpening... the never ending questions

Jonathan Ronnow, Sweden

>well, you made me try hollow grinding two of my japanese chisels last night. They are the cheapos that japan woodworker sells under the japanese woodworker brand, so I guess they are softer than the Iyoroi and Matsumuras. I will let you know when Ive whacked some wood with them. I used a tormek for the grinding so my hollow is even shallowe than yours I think, and can easily be honed away.

Time will tell. Bummer I got teased by Rob Lee about the new honing guide..... gotta have it =)

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