Thread: Advice Please.. first Japanese chisel

Paddy

I would just use a coarse water stone to square up the edge, then take it to progressively finer stones as per your normal sharpening routine. The blade is laminated and it's only a relatively thin layer of hard steel you need to work through, so it shouldn't be that difficult, or overly time-consuming.

Once you flatten the back properly, you'll reclaim a bit more real estate between the edge and the hollow. You'll also find that as you keep sharpening, the front edge of the hollow will gradually move back. The hollow you have on your chisel will have no effect on its life. I've seen photos of Japanese chisels that are less than an inch long still being used. Japanese plane blades are a different matter, and need to be tapped out when you hit the hollow, which is a skill in itself, but not chisels.

I've seen some people hollow grind Japanese chisels, and they seem quite happy with the results. I don't and I don't like it, but that's only my preference.

Hope this helps

Des

Des is correct re squaring up and also the hollow moving back.
I've always hollow ground my Jap. chisels and have no problems.

Originally Posted by Paddy

Treated myself to a 19mm IYORI chisel whilst on the MIK stand at the wood show.

When I got home noticed that the edge had been ground on a skew of about 5 degrees. Also that the hollow grind on the back came within 1mm of the edge (even less when the skew is removed.

Paddy, have you contacted MIK to see if they will replace it? This may save you more time than reworking it!

Originally Posted by Paddy

What is the best method for squaring up the end. I have been told that the steel is too hard for diamond stones and damages the stone.

I frequently use my diamond stones to rework old Japanese blades and can't say I have noticed any problems yet.... regularly flattening my waterstones with my diamond plates probably has a greater impact on them. Quality of the diamond stone may be an issue.

As suggested by Des, start by flattening the back. Also see the Sticky posts from soatoz (our resident guru) at the top of this forum on preparing a new Japanese chisel.

Originally Posted by Paddy

With the amount of material to removed, would not do much good to the water stones.

Well, that's just what waterstones were developed to do. Just start with #800 or #1000 stone and go from there.

Originally Posted by Paddy

Don't want to hollow grind as per normal chisel.

I wouldn't and soatoz recommends against it... see his Sticky posts.

Originally Posted by Paddy

Also, how much flat would you expect between the hollow grind and the cutting edge... I would have thought 5 mm would be more reasonable, or chisel life would be short.

Not sure what your thinking is there Paddy... it seems the other way around to me. The smaller the flat between the cutting edge and the hollow, the more cutting steel is still available for future sharpenning. The purpose of the hollow is to reduce the amount of hard steel to be flattened and of course the hollow will travel back with the edge as you sharpen the bevel and occasionally re-flatten the back. I have a couple of very old Japanese chisels that are almost down to the shaft and as can be seen from the attached photos (this chisel just as I received it from Japan), with only 10mm of useable blade remaining there is still a 1mm flat between the hollow and cutting edge .

Happy honing

Neil

Thanks guys for all the suggestions. As I have no experience with Japanese chisels, thought it would be wise to seek advice prior to getting on to MIK.

Sorting this one out will be part of the learning curve for me. Whilst I have always kept the backs of my chisels ,flat and polished. have never considered the need to remove material. .

Paddy

I would use a belt sander to square up the bevel. The skew is too great to do by hand - unless you have a 300 grit waterstone or 80 grit sandpaper... and a lot of patience.

I would use a 60 grit belt (this may be coarse but it will run cool), then 120 grit.

Once the bevel is squared up, then I go to my waterstones. I use Shaptons and go to a 1000, then 5000 and 8000. I may go to a 12000 for paring chisels.

Note, I keep the bevel flat - no hollow grinds on Japanese laminated blades please. Don't forget to hone the back of the blade. This is what keeps the hollow at bay. Hone the back to the same grit as you finish the bevel.

For the record I have a large number of Iyoroi chilsels, both bench and slicks. The bench chisels are ground at 30 degrees and the slicks at 25 degrees.

Regards from Perth

Derek

Only took me about 45 mins to get a great result. Started with the diamond stone and finished with water stones.

Found that the two faces of the chisel were not paralell, which made it impossible to mount in a honeng jig. Just used a fine file to correct the angle (almost 0.5mm thicker one side than the other!)

Think I am going to become a convert, have already switched to draw saw's.

Thanks for the advice ...............Paddy

Originally Posted by Paddy

Treated myself to a 19mm IYORI chisel whilst on the MIK stand at the wood show.

...
What is the best method for squaring up the end. I have been told that the steel is too hard for diamond stones and damages the stone.

...
Paddy

I have followed the thread with interest and thanks to all as I have no experience in these chisels though I do have one in a drawer waiting for me to get to it. Noone commented on the quoted statement. Surely there is no steel too hard for diamond or am I missing something ie the sadhesive between the diamond and the plate?

Pusser

Pusser

Can't see why the chisels would damage diamond stones any more than just normal wear and tear. I don't have any diamond stones so no experience there, but I do have one of Shapton's diamond reference lapping plates, and use the back for refining the edge on chisels and plane blades every now and then - I've not noticed any unusual wearing or damage to the diamond layer.

Paddy

You'll find that all of the standard-use Japanese chisels (and plane blades) are wedge shaped. That's how the hollow works. Hope you enjoy your chisel. They hold their edge well and really are a pleasure to use.

Des

Thank, I could not see why any steel would be too hard for diamond (against the laws of physics captain! as Scotty would say).

Good luck in Japan - you might get to see the home made bandsaw that featured elsewhere in the forum)

Pusser

I've never heard of steel damaging diamond stones either.. but it was one of the guys on the MIK stand that mentioned it to me!! I don't think that he was suggesting that the steel damaged the diamonds , but that the chisel dislodged them from the surface.

Caused no problems with my stone.

Paddy

As you are saying diamond is the hardest thing there is. Steel being softer will be cut by diamond. The laminated steel is usually between RWc 60-63. There are machining tips made from Boron Nitride that can machine metal that is up to RWc 68 at 200m/min!!!!!! Diamond is harder again.

I have had many japanese planes and chisels and have had no problem hollow grinding them first the finishing them on a waterstone. I got a big bundle of second hand ones and some had chips and so on that really had to be ground out. I use a wheel that is intended for carbide and am careful not to overheat the blade and have had no trouble at all.

Once the blade is in decent nick there is no need to grind it again. When it starts to lose it's edge a few quick minutes on waterstones will get it back to a razor sharp edge.

Studley

Originally Posted by Paddy

I've never heard of steel damaging diamond stones either.. but it was one of the guys on the MIK stand that mentioned it to me!! I don't think that he was suggesting that the steel damaged the diamonds , but that the chisel dislodged them from the surface.

I'm no expert on diamond abrasives, just 20 years of experience in using them in various forms, but my impression is that the MIK guy is right. Quality is all down to the matrix bond that holds the diamonds.

In the case of my 16" stone cutting circular saws (which start life with about a 12mm diamond matrix layer) the bond is designed to gradually break down to release the outer diamonds as they 'dull' to expose fresh cutting diamonds. To freshen up a blade I slice up old silicon carbide grinding wheels...like a hot knife through butter . It's the matrix I'm grinding away and that releases the 'used' outer diamonds.

My dremel-type diamond bits seem to work the same way, only in miniature.

But my diamond plates and 'stones' appear to have a single, or very thin, layer of diamonds that are held in a very strong bond that is not designed to release diamonds in the same way as the above applications. In fact, in the case of the larger plates, the flatness of the cutting surface is the required characteristic and any loss of diamonds would detract from that. As the diamond itself doesn't vary all that much in its quality, it's the bond that determines the 'quality' for the designated purpose, and price is likely to be a good indicator of that quality.

I have one credit card plate that I have used an estimated 20,000 times to sharpen everything from carbon steel to tungsten carbide tips (and everything in between) and, although now far from its best performance, I'm far from replacing it.... always immediately available in my top pocket... it's cost me 0.375c/use so far and counting down...

Neil

Originally Posted by derekcohen

I would use a belt sander to square up the bevel.

I would use Derek's belt sander method for this initial re-shaping phase if I already had his setup. One of these days I may reach the tipping point where I have so many blades to rework that I will stop doing it the long way and take time out to make up my own rig. Until then.....


Neil

A number of knowedgable woodworkers, who know steel, strongly recommend against diamond stones for blades. These include Steve Knight (Knight planes) and Larry Williams. Larry wrote (on Knots):

The diamond stone ... will last longer cutting honing stones than it will cutting steel. This is because the swarf created on the stone is granular and on steel it's stringy. The stringy swarf of steel wears away the matrix the diamonds are mounted in.

I have a few DMT diamond stones, some have been used on steel and some are reserved for waterstones. There are some blades - the thin/narrow ones - that I will only hone on diamond as they would chew up a waterstone.

Another alternative, which I have used with much success, is diamond paste on hardwood blocks. Make your own (renewable) diamond stones. And they are cheap!

Regards from Perth

Derek