| Joel's Blog|
| Built-It Blog|
| Video Roundup|
| Classes & Events|
| Work Magazine|
|The Tools of Stropping - 04/09/2013|
|Chris Pye's Woodcarving TV and Choward's Comes to TFWW - 04/02/2013|
|Combo Saw Filing Questions Answered - 03/27/2013|
|The Work Magazine Reprint Project One Year Anniversary and Index - 03/12/2013|
|Tell Us What You Think - 03/05/2013|
|The Mechanics of Stropping - Why Stropping Works - 02/26/2013|
|Things To Do This Weekend - Both Here and in London - 02/19/2013|
|Our Showroom Will Be Closed Feb 18, 2013 in Honor of President's Day. - 02/17/2013|
|Tools for Working Wood Opens a Pop-Up Shop - 02/12/2013|
|In The Belly of The Bevel - Or How To Ineffectively Sharpen Anything - 02/05/2013|
|Friends and Family - 01/29/2013|
|In Praise of Shadows - 01/15/2013|
|Treadle Lathe At 3rd Ward Show - January 4-5 2013 - 12/28/2012|
|The Drill Bits Are Here! The Drill Bits Are Here! - 12/26/2012|
|Choosing a Set of Carving Tools - 12/18/2012|
|Decorative Art and a Walk Through Central Park - 12/11/2012|
|Clamps For Christmas - 12/08/2012|
|Cheap!!!! The High Cost of Discount Culture - 12/06/2012|
|Is This Tool Sharp? - 12/04/2012|
|A Quick Update On My Last Blog On Mortise Benches Etc. - 12/02/2012|
Hours: M-F 9:00-5:00, closed Sat,Sun
Our Guarantee & Return Policy
Shipping and Sales Tax Info
Phone: 800-426-4613 or 718-499-5877 Visit Us in Brooklyn: Directions to Our Showroom
© 1999-2019 toolsforworkingwood.com
Powered by 01 Inc. Coded entirely in NYC
Is it simply incorrect, or a bad idea to hollow grind Japanese Tools?
Glad you opened this kettle of fish! No doubt a common problem.
What you didn't stress is the concept of convex bevel honing vs.honing a hollow or flat bevel. In the latter the edge is always in contact with the stone and only maintaining the angle is important. One or two strokes will sharpen the edge. The downside of this is that periodic regrinding is required. However, in the former case of a convex bevel a completely different concept is working. Here the edge is not sharpened but rather "exposed." Metal is removed from the belly of the bevel so as to work toward an edge that thus becomes sharp. Periodic regrinding is not needed. Watch Sellers sharpen. He starts always with a coarse stone and drops his angle as he pushes forward on the stone - affecting the belly of the bevel. So, in summary, convex bevel sharpening requires a completely different mind-set vs. micro bevel or flat bevel or hollow bevel sharpening.
You hone as normal starting at 30º but dip the handle as you go, to round the bevel slightly, but under the angle, not over. You keep going until you can feel a burr across the whole width. If this doesn't come up quickly (i.e. you are sharpening the belly as in your drawing) you move to a coarser stone and remove the belly until it meets the 30º edge. Then back to finer stone as necessary.
Paul Sellers does a good video of this http://www.youtube.com/watch?v=a6ykVzL2VAM and see other comments in his blog.
I hollow grind Japanese chisels but not all the way, ject to get rid of any belly. It's certainly non-traditional but it works and saves me time - so by definition it isn't wrong. If you want to be traditional don't do it.
I do mention starting at the belly method and then wiping out at the edge, which is a three word summary of what Paul Sellers teaches. You lift the tool as you go to insure contact. As I said above, it works, it's easy to teach, easy to learn, nothing wrong with the method. I think maintaining a flat is less work, just requires a slightly longer first lesson and more practice. In either case at some point you end up with a very steep angle which really should be ground. And in Paul's method sharpening paring chisels to a very low angle (15-20 degrees) will quickly result in the bevel angle being higher - which defeats the purpose of the very low angle (although I don't think Paul uses long paring chisels - but I could be wrong).
Needless to say you have a method that works, my point is that a lot of people don't have a method that works, or a method that works inconsistently. The reason is they don't realize that they are polishing a belly not sharpening an edge via one method or another.
I like it personally, because I can FEEL when the cutting edge is starting to abrade. I'd been doing the hollow grind and eclipse guide for 10 years and find the Sellers method faster and WAY more relaxing.
I sharpen pretty much the way you do but my point is that a lot of people have trouble sharpening because they are sharpening a belly without even realizing it. I don't have an axe to grind with any method that actually works.
I might have misunderstood Paul's method, I'm certainly not suggesting that it is ineffective, I don't think not having to ever go to a grinder is a good or bad thing. I hollow grind because it's faster, the end result is hopefully the same.
I discovered it for myself http://owdman.co.uk/howto/howto.htm
I think it was fairly normal, before the honing jig and accessories became so popular.
The key thing is to get a full width burr without lifting the handle and steepening the bevel.
Re: convex bevel sharpening.
With all due respect, I think that you are still stuck on the idea of sharpening the edge - and thus steepening it. So, you say, "In either case at some point you end up with a very steep angle which really should be ground." In reality if you change your point of view toward removing the belly of the bevel so as to expose the edge then you will see that the angle never grows, unless you want it to. You sharpen to remove the belly not to sharpen the edge. As you remove belly behind the edge you will reach the edge and a wire will form if you go far enough - but, a sharp edge can be had with out turning a heavy wire edge as you creep up on it gradually removing belly. Of historical interest most old tools seem to have been sharpened with a convex bevel. Also, Samurai swords are sharpened this way.
If you look at the method I was taught (click the link to Maurice's lesson in the blog) you can see it is pretty easy to maintain a bevel over time. I have tools that haven't been ground for decades but get sharpened regularly. Most retain the same angle, some get steeper over time when I am sloppy. For the past few years, since Barry Iles taught me to grind, I find hollow grinding everything saves time and effort.
I don't understand how having any belly allows you to have the ridiculously low angles you find on paring chisels or carving tools used for softwood. (as I am doing more and more carving my tools are going to lower and lower angles).
In any event whatever technique you use isn't the point of debate here. There are many ways to skin a cat. Each method has pros and cons. The point of this blog is that at some point of your sharpening you are sharpening at the edge. Lots of people aren't and don't realize that's why they are having trouble sharpening. I was just hoping to point that out.
N.B There is plenty of historic documentation that suggests that hollow grinding was a common, regular activity. That many old tools have rounded bevels isn't any indication of what was considered the most efficient way of maintaining a tool. The tools that were ground regularly would have worn out years ago and not survived. If we took the condition of antique tools found in the wild as any indication how they were used when they were used regularly the only conclusion would be all tools were dull and usually a little rusty.