sharpening chisels

[dirtydeeds]

ive not got japanese chisels

i sharpen my (western) chisels at 25 degrees then hone at 30 degrees, a double bevel


i am told that japanese chisels are sharpened and honed at the same angle

my three questions are

is this correct about japanese chisels

if it is correct, why do they do this (the japanese dont do anything by halves or for no reason)

is there any benefit in sharpening and honing my western chisels at one angle (in my case 30 degrees)

[sainty]

Jun 14, 2008 21:47:52 GMT dirtydeeds said:

my three questions are

is this correct about japanese chisels

if it is correct, why do they do this (the japanese dont do anything by halves or for no reason)

is there any benefit in sharpening and honing my western chisels at one angle (in my case 30 degrees)

Cant hep you on the Japanese side of things I'm afraid. The reason (one of the reasons) that we westerners grind and hone at different angles is because your honing stone doesn't remove material very quickly/efficiently. If you were to hone the whole "ground" face of the chisel every time you needed to sharpen you would be there for a long time. There is a school of thought (Jacob) that says you should have a rounded grind on your chisel, and eliminate the need primary/secondry and microbevels, (yes, three angles, which is easily achieved with a honing guide) it is also easier to sharpen by hand this way therefore speeding things up. I think that it is fair to say that this is a disputed method but it is not a method that I have tried myself.

The construction of Japanese chisels is different to that of western chisels. There are two laminations of steel, the cutting edge is made from a much harder steel and the back is much softer. The theory being that the cutting edge can sharpened to a very sharp edge but the softer back prevents the chisel being too brittle when struck. It might be this laminated construction that lends itself to a single honed angle. As I don't own any japanese chisels though this is strictly theoretical information that I can give you. I'm sure that there will be plenty of people out there that can offer real experience!

rgds

Sainty

ps you have started a thread about sharpening, I hope you can control it!!! ;D ;D ;D

[promhandicam]

Jun 14, 2008 22:15:59 GMT sainty said:

. . . you have started a thread about sharpening, I hope you can control it!!! ;D ;D ;D

more or less my thoughts too when I saw it - unless it is a deliberate wind up!

Anyway, regarding Japanese chisels - I do have some and I have honed them in the same way you talk about honing western chisels. It would take forever trying to hone the whole face each time particularly as sainty mentions, the cutting edge is very hard.

HTH,

Steve

[dirtydeeds]

sainty, you have a similar idea to mine

it must be a good idea

BUT

you are not quite sure why

[dirtydeeds]

this is no wind up. i dont know and would like to know












but a reply like this could be a wind up

[engineerone]

i know that i am going to regret this but

most japanese chisels are designed to be bashed with a hammer, so it might have been considered in japan that in view of the way the chisels are made, a single bevel would be logical.

as i have said before i was surprised to find on some of my late father's chisels which i had not seen before, and he was no woodworker, but a stone mason, there were in fact two bevels, and also he had flattened the back(face)

based on nothing but my own experience (limited ;D) i think most english chisels other than mortice ones are not necessarily designed to be wacked with a hammer/mallet thus with hand work, there is more accuracy and freedom of movement with the double bevel. but only in a cabinet making type environment.

the advantage of the double edge is that you do not have to re grind too often. in my case i take it off the tormek, and then add the secondary bevel, and strop. gives a long lasting edge, but i will not need to grind for sometime.

i have the understanding that the "average" japanese carpenter have mainly used waterstones for their sharpening, so it might seem easier to produce one bevel only.

however, without a jig it is almost impossible to absolutely ensure that you keep to the same angle all the time, so i think they all have micro bevels.

i wonder how long it will be before i have to remove the hollow on the back of my japanese chisels

paul

[mrgrimsdale]

There is a school of thought (Jacob) that says you should have a rounded grind on your chisel, and eliminate the need primary/secondry and microbevels, (yes, three angles, which is easily achieved with a honing guide) it is also easier to sharpen by hand this way therefore speeding things up.

Yes thats it in a nut shell

I think that it is fair to say that this is a disputed method but it is not a method that I have tried myself.

You should try it!
It may well be disputed but it is the way everybody used to sharpen before they started worrying about it and began burbling inanely about bevels, jigs etc.
It's a bit like the planing thread - if you think about it too much it becomes impossible, or you have to go on a course!
It works really well - all my stuff is sharper than it ever was, with much less effort, with just one double sided oil stone. Well 3 actually - but more by chance than choice. One alone would just about do.

cheers
Jacob

[Alf]

Jun 14, 2008 22:15:59 GMT sainty said:

The construction of Japanese chisels is different to that of western chisels. There are two laminations of steel, the cutting edge is made from a much harder steel and the back is much softer. The theory being that the cutting edge can sharpened to a very sharp edge but the softer back prevents the chisel being too brittle when struck. It might be this laminated construction that lends itself to a single honed angle.

I think the construction probably has a lot to do with it. The soft backing to the hard steel means there's no saving in time by using a secondary bevel, as opposed to the case with Western chisels with hard steel right from front to back. Of course there's possibly an element of "a wise old man wrapped in rice paper at the top of Mount Fujiama told us it must be so, so that's what we do" as well, but who knows? ;D

Cheers, Alf

[modernist]

Jun 15, 2008 7:37:14 GMT Alf said:

I think the construction probably has a lot to do with it. The soft backing to the hard steel means there's no saving in time by using a secondary bevel, as opposed to the case with Western chisels with hard steel right from front to back. Of course there's possibly an element of "a wise old man wrapped in rice paper at the top of Mount Fujiama told us it must be so, so that's what we do" as well, but who knows? ;D

Cheers, Alf

I think that's right, especially so if you use a waterstone which cuts quicker and should not have any problem with the softer backing.

I've always sharpened mine in the Western way but with a tormek and waterstone which is quick easy and effective (and a Veritas honing guide). Like Jacob my chisels area sharper than ever.

Having said that I use the triangular section cabinet making type, no doubt someone can tell me the Japanese name and I tend to use them only for fine hand work as they are prone to chip at 30deg if walloped. they are definitely sharper than western style.

Theres more than one way to skin a cat

Brian

[andy king]

Jun 15, 2008 7:23:13 GMT mrgrimsdale said:

It may well be disputed but it is the way everybody used to sharpen before they started worrying about it and began burbling inanely about bevels, jigs etc.

cheers
Jacob

Everybody? Not me. I was taught to freehand a secondary bevel by people far older and wiser than i'll ever be and i bow to their knowledge every time.

[mrgrimsdale]

My theory is that "secondary bevel" only meant anything to those using a grindwheel.
Many wouldn't have had access to one and would have done all their sharpening on a flat stone by hand - in which case primary/secondary bevels become meaningless. You only need to remember to grind on the coarse side at an angle less than the desired honing angle. Round convex bevel is easier/faster than a flat bevel. Thats all there is to it.

cheers
Jacob

[modernist]

ground or stoned it must always have been easier to touch up and edge if it were narrower, notwithstanding the round bevel school.

Brian

[engineerone]

so how is a so called round bevel anything other than a double bevel ;D

my recent experience with chopping mortices in oak and cherry as well as dovetails in those materials plus cedar is that although the tormek edge is quite good, a flat strop and touch up on a stone, or diamond is even better.

the cut is then clean and rather like a knife through butter, even with a japanese chisel and no mallet/hammer.

paul

[mrgrimsdale]

ground or stoned it must always have been easier to touch up and edge if it were narrower, notwithstanding the round bevel school.

Brian

Yes. A convex bevel (in good nick) has an infinitely small bevel to touch up i.e. it only reaches 30deg at the very edge, and thereafter it is less. Which is why it is faster. Also easier - you don't have to struggle to maintain a fixed 30deg, you just have to ensure that you don't exceed it.
Is there a "round bevel school"? Who else is at it? Hands up!

so how is a so called round bevel anything other than a double bevel

If anything it's an infinite number of bevels: all angles from 30 down to zero (or something less, doesn't have to be zero).

cheers
Jacob

[modernist]

I'm just in the middle of gluing up some 3m frames so I can't indulge in the sharpening war till later ;D

As I was cleaning them up this morning with my waterstoned LN I thought it can't get any better than this. Slightly curved cutting edge, sharp and fine, I had the 110mm wide middle stiles smooth in 3 or 4 easy stokes with a finish like glass and no visible scallops.

Each to their own

Except

Whether the secondary bevel is flat or curved is irrelevant. the bit your touching up is the final edge in either case. Personally I'd rather knock back the secondary area from time to time on the grinder than file away at it on the stone every time I sharpen

Off to glue another frame

Brian

[derekcohen]

Hi Jacob

While not disputing that you are able to achieve a sharp edge on you chisels with a rounded bevel, I am curious to understand how you use your chisels.

I use both Western and Eastern chisels. I do not hone secondary bevels on any, with the exception of my mortice chisels. I view a rounded bevel and secondary bevel to produce the same problem, that is, you can only use one side of the chisel.

Don't you also use a chisel bevel down? When I do so, the bevel effectively becomes the back of the chisel. Accuracy will be affected unless this is flat. So both rounded and secondary bevels become the equivalent of backbeveling a chisel (and you know what DC -the other DC - has to say about that).

As I mentioned, the only chisel I add a secondary bevel to is a mortice chisel. I aim for 35 degrees on top of a 20 degree primary bevel. This is not to make sharpening easier, but to aid the blades' edge penetration into the timber (20 degrees enters more easily than 35 degrees), while aiding edge retention.

It seems to me that a great deal gets spoken about honing a chisel blade for the ease of obtaining a sharp edge. However, while sharpness is important, I prefer think of how sharpening affects the way a tool may be used, and this is one factor which determines how I will do it.

Regards from Perth

Derek

[mrgrimsdale]

Hi Derek
Interesting point (no pun intended)! I'll have to think about it.

OK thunk as follows: yes I do use chisel bevel down e.g. clearing out a housing. Can't see it makes any difference the convex bevel, if anything there's an advantage in that you get a precise graduated change of angle if you tilt at all, perhaps?
On the job you are not able to see exactly where the bevel is contacting the wood so I can't see it makes any (much) difference whether its convex, flat, 2 or more bevels. You do it by feel.
Come to think - a hollow ground bevel might be problematic compared to the above.

I'll think on!

cheers
Jacob
PS

you know what DC -the other DC - has to say about that

No I don't know - am still banned from over there.

[andy king]

Jun 15, 2008 10:21:59 GMT mrgrimsdale said:

My theory is that "secondary bevel" only meant anything to those using a grindwheel.
desired honing angle. Round convex bevel is easier/faster than a flat bevel. Thats all there is to it.

cheers
Jacob

A theory. Simply that, but not proven.
As for a your round/convex bevel being faster? I dispute that as well. I'll freehand hone any iron to razor sharpness in seconds if the initial primary bevel is good, where as trying to find where you last left off by round honing could have you faffing around before you find the right spot to raise a wire edge.
Rounded honing was instilled in me as bad technique by my peers and I still bow to their superior knowledge.

[engineerone]

well maybe it's me but

my mortice chisels are tormeked, then quick rub on the diamond and finally a good strop both sides on leather. nice polish

anyway have just cut two 3.8th mortices about 3/4 deep and same long in cherry, by hand, not even a mallet

took about 20 minutes each including measuring and then levering out the waste, and fettling the joint with the tenon.

sure if i did more it would be quicker, but happy to be able to use hand pressure alone ;D

so my chisels must be sharp too

paul

[dirtydeeds]

my left forearm generally has no hair because i test the sharpness of the blade with a dry shave

if you can dry shave with a chisel it IS sharp

it also means that you can shave hinge mortices to depth with wrist presure alone

[Alf]

Hi Derek - long time no speak!

Jun 15, 2008 17:11:30 GMT derekcohen said:

Don't you also use a chisel bevel down? When I do so, the bevel effectively becomes the back of the chisel. Accuracy will be affected unless this is flat.

Two things occur to me in response to this. First, exactly how accurate does one need to be when using a chisel bevel down? I can't, off-hand, think of anything, but it is Monday morning. Secondly, I can't recall ever having any trouble working a chisel bevel down off a secondary bevel. Whatever the bevel it's still a matter of feeling for, and then holding it at the right angle, innit? I'm all for the natural jigging provided by a tool set up in a certain way, but this one doesn't strike me as a good argument to relinquish the benefits of hollow grinding and secondary bevels.

Oh, and for the benefit of all, a word of warning on the low primary/high secondary bevel on mortise chisels. It's okay on Oval Bolstered MCs, but don't try it with a crappy 1960s Marples sash mortise chisel - it probably won't cope with the extra penetration if my broken example is anything to go by...

Cheers, Alf

[mrgrimsdale]

Jun 15, 2008 19:27:03 GMT engineerone said:

anyway have just cut two 3.8th mortices about 3/4 deep and same long in cherry, by hand, not even a mallet

took about 20 minutes each including measuring and then levering out the waste, and fettling the joint with the tenon.

sure if i did more it would be quicker, but happy to be able to use hand pressure alone ;D

Yebbut yer sposed to hit a mortice chisel with a mallet - that's why they are like they are. Then your little mortices would have taken about 1 minute instead of 20. Yer not sposed to scrape & scratch them out

cheers
Jacob
PS and Alf, how did you break your sash chisel? I bet you were levering
Not what sash chisels are designed for
They are intended for narrow but deep mortices such as you need for through glazing bar tenons, most often found in sash windows typically 2 to 3 inches deep, 1/2 inch square. Hence the name of the chisel.

[derekcohen]

Hi Derek - long time no speak!

Hi Alf. Yes it has been far too long. I must hang out here more.

I can't recall ever having any trouble working a chisel bevel down off a secondary bevel. Whatever the bevel it's still a matter of feeling for, and then holding it at the right angle, innit?

I agree. At the same time I find that working with a chisel that is held BD is often called upon in situations that require greater precision - usually in tighter areas but usually because paring BD exerts more control over the grain (in my opinion . It helps then to be able to use the bevel as a guide.

I'm all for the natural jigging provided by a tool set up in a certain way, but this one doesn't strike me as a good argument to relinquish the benefits of hollow grinding and secondary bevels.

I hollow grind all my non-laminated blades. I do so at the angle I want to hone them so that the microbevel/secondary bevel is co-planar with the hollow. (This also makes freehanding honing a doddle - which seems to be the topic in the latest FWW mag, which I have yet to read). So the bevel remains effectively flat.

Thoughts?

Regards from Perth

Derek

[Alf]

Thoughts? Erm, I dunno. Evidently I must be considerably more skillful than yew* sounds boastful, rude and incredibly unlikely! But after all the bevel is still there, to guide you. Oh well, it's so flippin' long since I did any timber torturing it's probably best if I sit on my tongue anyway!

Cheers, Alf

*apologies to Harry Enfield

[mrgrimsdale]

Jun 15, 2008 18:51:54 GMT andy king said:

snip
trying to find where you last left off by round honing could have you faffing around before you find the right spot to raise a wire edge.

You start by honing at 30 deg. If you don't get a wire edge fairly quickly you back it off by being more vigourous but at a lower angle, and then revert to 30 deg. If not good enough you back off again but on a coarser stone. Sounds fussy but in fact is very quick and comes naturally once you have the routine sorted out.

Rounded honing was instilled in me as bad technique by my peers and I still bow to their superior knowledge.

Rounding is deprecated because it usually means lifting the angle to get a wire edge sooner - altering the angle until it need regrinding. You avoid this by 'dipping' to deliberately create a convex bevel but with an edge staying at the angle you want, and backing off the rest of the bevel at the same time.
Doesn't take long to get it. A visual guide to 30deg can help, such as this cheese shaped wedge at 30deg, with pencil line at 25, sitting between a fine and a coarse stone.



Here's a convex bevel on a 2 1/2 inch chisel. Apologies to those who have seen it before!



cheers
Jacob