Thread: should new chisel edges be square?

If you are talking about the angle of the side wall relative to the back of the chisel, typically they are tipped in by a degree or two. This prevents binding if you are using the chisel to lever out a chip.

If you are talking about the angle of the cutting edge relative to the sides, that should be square, but that's something I would just take care of myself, as I would sharpen a new chisel myself before using.

I agree completely. I sometimes find new nomi to be off, and just square them up on the first polish and honing.

I'm talking about the angle of the cutting edge in relation to the sides

thanks both for the quick replies twill get the waterstones out!

Paul

Believe it or not - you should be at least thankful that they come with an edge (although these days, most tools do. But I found some of mine to be a little off as well). Sometimes, you get brand new tools without a sharp edge, just the initial bevel angle established. Imagine having to remove about 1 mm of depth just to make a rough-ground edge and then have to complete each tool with medium and fine stones (times the number of tools in the set). Same for new kanna (its no fun having to remove the same 1 mm of depth across a 65 or 70 mm edge, believe me). You may have read previous threads lamenting the slow progress when trying to remove lots of metal.
If you ever chip an edge (my guess is you probably will - no reflection on your skills or abilities, its just inevitable) you will have the pleasure of removing enough metal (maybe a lot) to make the chip disappear. It will make straightening a crooked edge seem not so bad.
Anyway, welcome to the forum.

Steve

p.s., you can gradually even out the edges over a couple or more sharpening sessions with larger chisels. It can be tiring doing a lot of sharpening at one time when there are lots of stones to go through or much metal to be removed. Sharpening when tired is not recommended as inattention can be both dangerous and provide inferior results.

Hi Steve

thanks for the advice

these are my first new chisels since I started out with a couple of Stanley 5002s 15 years ago. Everything else has been second hand and has generally been put to a 240grit waterstone to get a rough straight edge before working up through honing and polishing stones. I bought these on recommendation as I'm doing more woodwork now so I think I'll do one at at time starting with the small ones! Having sorted the backs out would you start with a 1200 grit or take off the edge with a 240 first to straighten out the edges?

thanks

Paul

Paul,

As far as a starting grit goes, its up to you. Certainly, with small chisels 1.5,3, 6 mm), 1200 will be fine as there isn't that much metal to remove. You would save a step not starting with a coarser stone, but you can. With the larger sizes, its a trade-off between more work on the 1200 and skip the coarse, vice a bit faster starting with the coarse and having to add in the medium (although it doesn't take much time on a 1200 to remove the 240 marks). You could try starting on the 1200 and see how its going speed-wise and go back to the 240 if it seems too slow.

Or - you could do like I do - use the chisels as they are and then deal with straightening the edges at the same time you're removing the chips

Steve

Hi, Paul (and you other reprobates),

Welcome aboard (I forgot to say last time).

I know it's considered sacrilege, but when I receive a tool with blunt edges, I use a Jet waterstone sharpening wheel. Clearly, you don't want a hollow grind, so I use the side of the wheel, which is quite flat, or otherwise can be trued with little trouble.

This is especially helpful when you have to sharpen a whole new set.

The key is to be really careful of your angle: it's (to me, at least) a little weird to work on the vertical, and finding whether you have to skew the blade this way or that to get the smoothest finish possible.

As a rule, I'm a purist. Would much rather do it by hand. But I also often just don't have time or energy to put in so many hours of work starting on a kanna or nomi blade -- or worse, a whole set of them -- that have arrived blunt.

You should definitely hear what the others have to say on this, too -- they may well blast me off the forum for suggesting such a callous approach...

I'm not saying it's the ideal approach, Paul, just that in a jam, you can get good enough quick results to move on to the medium grit stone with a fair edge.

Good luck!
Becky

Hi Becky,

Well, why not? So long as you are careful not to overheat the edge, I suppose any method is valid. Me, I'm too cheap (maybe stubborn, too, but not a purist thing) to spend money on a machine when I have the stones and the time. Certainly, for those of you who need to make a living using your craftspersonship, saving time is usually a higher priority.

Also, I (we) know there are some out there who have no qualms at all about hollow grinding and micro/secondary, etc. bevels, so whatever works is up to them. (although, I object when I hear somebody - I recently read an article - who uses Japanese tools and sharpens them with Arkansas oil stones - talk about wasted potential)

I believe (just my opinion - no proof or basis in fact) that tools that come with a skewed edge are done on a machine anyway. I can't imagine a living human spending the time to sharpen edges by hand and accepting (or the boss who's paying them) anything but perfectly square. Machines save time and labour, and if a side effect is a slightly off square edge, well the end result is a more economical price. I doubt that expensive tools would ever be sold this way, as one of the reasons they are expensive is they are sharpened by human hand (which is costly). Tools which are sold with dull edges (the purchaser is expected to sharpen them) are slightly less expensive because of this fact. Again, this is all conjecture on my part.

Steve

Freedom to create
Is impossible for those
Who slave to the way

Originally Posted by yojimbo

Clearly, you don't want a hollow grind....

Becky - do you say that for aesthetic or technical reasons?

Neil

Hi, Steve and Neil,

First:

So long as you are careful not to overheat the edge, I suppose any method is valid.

That's why I like the Jet -- it's cheaper than Tormek, and is also water-cooled.

Neil -- I shouldn't have said "clearly" -- that was pedantic of me. While I'll sometimes use a hollow grind, and always a micro-bevel, on Western tools, I much prefer to keep J tools flat. I find that if you take the time to sharpen and hone with waterstones, they'll hold an edge pretty much forever. As I noted in another thread recently, I worked not too long ago with a timber nomi, carving a large piece of Matsu. That nomi held its edge for two solid days of pounding, with barely any honing (on a strop with green rouge) needed. It was amazing. So I don't see the need to use either a hollow grind or a micro-bevel.

Just me, y'know. My "clearly" was totally out of place.

I've read some posts by woodworkers (possibly here, but maybe elsewhere -- can't remember) who complain that they have to resharpen too often, and so they use coarse stones or grinders to restore a good edge. I generally find that if you take the time to work the metal on a kanna or nomi thoroughly through medium and fine grits, working out all the scratch marks at each stage, and doing so long enough that the (natural) stone material compresses itself into a finer and finer grit, the time spent is far less than doing a quick sharpen and then having to resharpen often.

This, then, is the main reason I prefer the flat bevel.

Hope I've been lucid -- a little short on sleep...

Becky

There is no problem grinding Japanese Tools on a bench grinder. Just don't overheat them or you can muck up the temper of the steel. With Plane Blades they have a hollow in the back you will have noticed if you have one.

Guess how they put that in there? They use a really big grinding wheel and just grind it out. It is all productivity and if you can't belt the work through your shop you are in trouble.

I did notice references to micro bevels. This is a popular technique with Western Blades. The Western Blades are made from different steel to the Japanese ones. When you sharpen a big problem due in large part to the blade being hard all the way across is that you get a bit of rolling as you sharpen and so put a shoulder on the blade. Effectively a blunt blade. So to get around this raise it up and put a tiny micro bevel on it. This means the bevel goes all the way to the edge.

Back on Japanese blades the back is soft. If you just keep the weight of your hand on the edge you are trying to sharpen the soft stuff on the back will look after itself. Of course holding the lot on the stone while just trying to keep the weight on the sharp edge makes it very easy to sharpen by hand.

Hollow grinding is no issue. Grind the blade ready for the stone and stone it off sharp. If there is a good edge and some hollow left it is no issue. As you sharpen the hollow will disappear.

If your blades are chipping consider the angle of your bevel. A really small sharp angle will expose a lot of the hard brittle steel without the support of the soft steel. This makes it very easy to chip. Remember that Western Blades include stuff like Chrome and Nickel that gives them good toughness. Angles that might seem just fine based on western blades may not be very good on Japanese Blades.

Studley

Becky, Steve, Studley, et al

OK, we are on the same page on this one. Power grind if you need to remove large quantities of metal but do so carefully to avoid de-tempering and de-laminating the blade... another recent thread on this board (What do you use for removing a lot of metal?) also covered that topic. Also worth mentioning, while on the topic, the slower surface speed of a belt sander is less inclined to 'burn' the cutting steel and maintains a relatively flat bevel.

Otherwise, the combined thin hard cutting edge layer + soft backing layer(s) of Japanese blades don't need hollow grinding and micro bevels for regular sharpening the way solid steel Western blades do. Although, I have read that master sharpeners in Japan will give a top class kanna finishing blade a one stroke 'micro-micro' bevel.

Having said that, an aesthetic has developed around the Japanese blade due, in part, to its flat bevel, with high class blades giving some attention to the soft layer/s which is/are polished as part of the sharpening process. Such things as the Jihada/Jigane grain in the soft layer/s and mokume-gane (damascus style lamination) are admired and appreciated. Hollow grinding would obliterate some/much of that detail.

Anyway, that is why I asked Becky if it was for technical or aesthetic reasons that you wouldn't hollow grind Japanese blades.

Neil

All well said, Neil. Though I've never tried the sander... kinda makes my teeth hurt to think about it...

Also might mention the beautiful haze created by natural waterstones, which I believe is called kasumi. Man-made stones will give you a spectacular mirror finish, but I have to say, I prefer the cloud-like haze from natural stones.

Anyone want to discuss uradashi as a footnote to Studley's post? Anyone with more experience than mine? (Uradashi, for the uninitiated, is the method of hammering down the back hollow so that it again meets the blade, once the blade has been sharpened past the first border of the ura/back hollow of the blade.)

And -- slightly off-thread here -- anyone have a technique for cutting down large waterstones that won't kill either the stone or every saw blade you own? Bought a gigantic zebra stone, and need to cut it into more economical pieces so I'm not always removing more stone than I need to in order to flatten it. Wore one saw (a fairly solid but inexpensive one) down to little bitty nubby teeth...

Sorry for the tangential query, but... well, I'm here, so I thought I'd ask...

Thanks, folks.
Becky

Hi Neil,

I won't hollow grind a laminated blade because I feel you weaken the tool (there is less metal behind the edge) and its ugly and it does obscure the hada (I do like to "see" the ji-gane - and its not so much a function of a "high class" tool, its just the steels used by the blacksmith to make up the ji-gane, sometimes there is a contrast which is visible, other times not). Again, I know people do it and don't seem to have a problem. Its not so much about right and wrong ways to do things, just different strokes for different folks.

I wonder when the "masters" add there one-stroke micro bevel? I doubt it is when the blade comes off the finishing stone (but I don't know that), but rather at some point after using the blade awhile when they are able to sense the change in cutting ability and know such a technique will be of benefit vice going back to the stones. I know Odate, for one, is opposed to the concept of a micro bevel.

Steve

I just read Beck's reply, so will add some comments in here.

Uradashi - I'm no pro, but have done it against a block of wood with good results. Others preach using a metal backing, but again - more than one way to hammer your back (or shoulder?). Key point is to be accurate with your hammer taps.

As to the big stone, my suggestion would be to use a tile/ceramic type blade (one which can be used dry - less complicated unless you have the proper watering system with the saw) in a table saw or skill saw. Failing that, maybe a hacksaw with a supply of cheap blades.