Hamaguri edge and Flat bevel

[Brian Holcombe]

I wanted to detail a hamaguri bevel and flat bevel for interest of discussion;

Flat bevel (without micro bevel)

http://i27.photobucket.com/albums/c181/SpeedyGoomba/E60D43C2-9419-4C27-9044-3624EAAA4340_zpsvca2ddg3.jpg

Zero distortion in the reflection

http://i27.photobucket.com/albums/c181/SpeedyGoomba/D77CD9DC-BB93-444A-8ECD-B7D24A53F261_zpsdmnncrce.jpg

Hamaguri (curved) on the left

http://i27.photobucket.com/albums/c181/SpeedyGoomba/DDAB5842-9001-4853-A5C9-D58C220A560A_zpspihps7ii.jpg


Hamaguri on the left again

http://i27.photobucket.com/albums/c181/SpeedyGoomba/AF49221F-CE2E-41F1-8CD4-7AC578DE623C_zps2vomenrw.jpg


I thought I would take a moment to detail these since they were discussed in the freehand thread. Basically the only way to make a hamaguri edge is in fact freehand, however it's not always wanted. Only in certain circumstances would you want one, really anywhere where you need something super strong but not necessarily as sharp.

I've been chopping rock maple and so my bevel is a hamaguri, if I were working softwoods I'd probably reduce it or remove it to be more like the paring chisel.

[Derek Cohen]

Brian, I am curious about the need for a hamaguri bevel (and just so you know, this is the first time I have heard the name).

As you know, I work almost exclusively with hardwoods. Most of them are no doubt much harder than the rock maple you are using (with which I am familiar).

My slicks are by Kiyohisa (as you may recall), and these are only pushed. They have a 25 degree flat bevel, since I wish them to be traditional.

I only freehand chisels (mostly other blades as well), so when it comes to my Koyamaichi dovetail chisels I go down a non-traditional route. I hollow grind them, and do so almost to the edge of the bevel, using a Tormek (to keep any heat down). This method ensures really fast re-sharpening (as I hone on the hollow). These chisels get wacked into some seriously hard, abrasive and tough wood yet have never chipped or failed in any way that would make me question the method of preparation.

Now a hollow grind is the very opposite to a hamaguri bevel. Why do you think that this (extra) work is really needed?

http://i13.photobucket.com/albums/a262/Derek50/Chisels/Kiyohisa/11.jpg

http://i13.photobucket.com/albums/a262/Derek50/Chisels/Koyamaichi%20chisels/Stu-chisels4.jpg

Guess which is which. :)

Regards from Perth

Derek

[Christopher Charles]

Makes sense. Rock maple? Now I'm curious...new project?

C

[Brian Holcombe]

Chris....nah, same project just more of it, lol. I'm using maple for the drawer sides.

Derek, I won't say it's required by any means but a combination of a hamaguri bevel and a very hard cutting edge makes for a chisel that goes a great deal of time with just the plain strop between sharpenings. However, in my experience still makes a very clean cut.

Those Kiyohisa's are damned sexy and 25 degrees is very impressive, especially in the woods that you cut. It's a testimate to the quality of Kiyohisa.

Do you maintain your bevels in the traditional method on the Kiyohisas?

I have worked on Ipe with handtools, so I understand your pain, lol.

[david charlesworth]

Brian,

A simple sketch shows that, at the same sharpening angle, the flat bevel has more metal supporting the edge than the elegant convex curve.

I have never been able to fathom the purpose of the curve. (Except for levering with mortice chisels).

Help?....

David

[Brian Holcombe]

Do you feel it impossible that there is a practical advantage to the shape that may be easily overlooked? Is it possible that the extreme edge being at a high angle is better than having the full bevel at that angle in some aspects.

It's not proper to lever out with Japanese mortise chisels, they are made with a very big section of hard steel at their edges and so the extreme edge can chip if you lever with them. I've found this edge to be easier to chop with than a flat bevel at the same ultimate edge angle.

[ian maybury]

Definitely no claims to expertise or historical knowledge made here.

Judging by the ever eminent Mr. Google just now 'Hamaguri' (clam shell) seems just to be a general Japanese term that's applicable to all sorts of edges - including especially chefs knives, swords and who knows what. While there's not much mention of it in connection with chisels, the purpose seems basically as Brian suggests to be to deliver a thicker and more damage resistant edge. It also in the case of chef's knives allows a usefully flat/shallow/almost vertical bevel on the cutting side, but helps to separate away the cut piece of wet whatever to the other with minimal suction/stiction.

Judging by the many pages of minutiae coming up on the web it seems as in most of these things originating in the east there's a tendency for various western groups to get cultish, mysteryish and one uppity about them.

it seems likely though (??) that the reality is pretty straightforward - that it's the edge you end up with if you run into a problem with a single bevel edge ground at some existing angle chipping, and put a steeper microbevel on to strengthen it. Rounding over afterwards may deliver some benefit in certain situation (when chopping on chefs knives above?), or maybe it's mostly aesthetic?

Must say my way of looking at this sort of stuff (hollow bevels/flatbevels/microbevels) is that it's another practial technique to have available in the armoury - to bring out if problems arise. There's by definition no ideologically absolute right or wrong - in that a very good quality chisel may function perfectly well at a given angle with a hollow or a flat bevel, while one with poorer steel or heat treatment may in the same situation chip like mad and benefit from said micro bevel....

[Brian Holcombe]

I feel similarly to Ian, I'm not part of the cult, but I like and take alot of aspects of it, the Hamaguri edge partially being one of them;

This is after a full day of chopping dovetails;
http://i27.photobucket.com/albums/c181/SpeedyGoomba/F8CF4B9D-CEC2-43D2-935C-186240097858_zpsowlnacp7.jpg (http://s27.photobucket.com/user/SpeedyGoomba/media/F8CF4B9D-CEC2-43D2-935C-186240097858_zpsowlnacp7.jpg.html)

Having used plenty of chisels and variety of edges at this point I think it's significant.

[Malcolm McLeod]

Brian,

A simple sketch shows that, at the same sharpening angle, the flat bevel has more metal supporting the edge than the elegant convex curve.

I have never been able to fathom the purpose of the curve. (Except for levering with mortice chisels).

Help?....

David

Pardon the intrusion, as I'm WAY out of my element here...

But I saw a special on one of the big-number TV channels about Japanese swords and this curved sharpening. The theory presented was that the blade presented less surface area in contact with the material being cut, and so less friction. Essentially 2 points of contact: one tangent contact of material on the curve wedges the already cut material out, allowing the second actual cutting edge to penetrate deeper.

[ken hatch]

Brian,

The bevel on the first chisel looks like it was finished on a natural stone, a beautiful bevel. It's a sick puppy that loves a beautiful bevel.....:), That or older than dirt.

ken

[Reinis Kanders]

Looks great!
Roughly how long does it take? Do you do this for special occasions?

[Brian Holcombe]

Ken, Oh, do I love a nice bevel :D Thanks for the kind words, both were actually finished on the same Nakayama asagi, but the hamaguri bevel will mute the contrast in some lights.

BTW, Have you noticed your Kikuhiromaru to show a damask pattern in the jigane? I found it in mine and I am assuming currently that it shows from a great deal of cold work?

Reinis, thank you! Doesn't take long, I make a flat bevel first then work it a bit more freehand when I want the bevel to become a hamaguri shape.

[Stanley Covington]

I have never heard the term hamaguri used for chisels, but only for swords and knives (and chonna, but the shape described is different than for sword or knife). It translates to clam, a good descriptive word for the curved bevel.

A curved bevel is very handy when the chisel needs to be used to make a scooped cut. Much easier to do than with a straight bevel. It is a common sharpening technique for carving chisels, therefore.

Geometrically, it clearly gives the thin metal at the cutting edge more support than a straight, flat bevel, but in deep cuts, it experiences increased friction. If you are chopping hard and fast, and keep the bevel oiled, this is not a bad thing because it tends to kick the waste out of the way with more force.

There is a tendency, even among skilled professionals, to unintentionally gradually abrade the bevel a bit shallower (lower) with each sharpening. When the angle gets too low, the edge starts to fail, and the craftsman then hand grinds a secondary, steeper bevel, and the curved bevel is created.

But there can be no denying that the curved bevel takes longer to sharpen, so except in the special cases mentioned earlier, most guys will make an effort to work the blade gradually back to a flat bevel.

A curved bevel makes no sense for a push chisel, except, as mentioned above, for carving or making scooped cuts.

All that said, there is nothing physically wrong with a curved bevel: They cut just as well as a flat bevel of the same degree of sharpness.

弐円

Stan

[Brian Holcombe]

Thank you Stanley, I appreciate your weighing in!

[Pat Barry]

This is what my bevels always seem to look like when I freehand hone them. I always thought it was undesired. Seems to me there is no benefit regarding freehand paring but for chopping with a mallet it does improve the edge support.

"BTW, Have you noticed your Kikuhiromaru to show a damask pattern in the jigane?" --- WTH does this mean? Way too out there for my understanding.

[Brian Holcombe]

Jigane is the soft steel/iron that makes up the supporting side of the lamination. Hagane is the hard steel which makes up the cutting edge and face

Damask, with regard to steel generally refers to layered patterns. This is a faint damask, which I've come to find out is from the age/composition of jigane (soft steel backing).

[ian maybury]

Hi Pat. It seems like a curved bevel cuts just fine - even judging by my fairly informal and DIY oriented hand sharpening over many years. :)

Chances are that the bigger issue with round bevels is that it's still necessary to precisely control the actual bevel angle right at the cutting edge.

If it starts out as a more shallow a 'V' than the steel can handle in a given situation then it will likely chip.

If you allow the chisel handle to drop even a little while honing a round bevel it will likely lever the cutting edge up off the stone and mean that there's no actual sharpening going on. If we don't have tight control of our honing angle the consequence of this can be that we're inclined to lift the handle a bit more every time we sharpen to ensure it doesn't happen. (maybe to reduce the amount of honing required too). Then the bevel angle at the edge gets gradually steeper.

Stropping may be a bit more tolerant of bevel angle inaccuracies, but only for a while…

The bottom line seems to be that there really isn't any free lunch - there's various means of honing and final sharpening, but pretty much all (once you're planning to use a tool for more than a honing or two) require good control of the bevel angle....

[david charlesworth]

The curved bevel works extremely well for for upside down or carving work, but it does not have more steel supporting the edge, if the sharpening angles, at the tip, are the same.

David

[ian maybury]

It's relative/down to where you start from/how you conceive of the convex being formed David. No debate - just differing scenarios.

If you create a single bevel cutting edge at a given angle, and as you imply create the convex curve by removing metal solely from further behind that edge/from the back of the chisel - then the bevel angle right at the cutting edge must remain the same and the amount of steel actively supporting the edge and the chip resistance the same.

If alternatively you add a micro bevel over an existing single bevel cutting edge and fair that in (the way a convex is most likely to arise in practice? - as a response to a chipping problem) - then it will as micro bevels normally do steepen the bevel right at the cutting edge from the original angle - and result in a stronger and more chip resistant edge.

[Brian Holcombe]

Ian's experience matches with mine. I rarely setout to create a hamaguri bevel, instead it's an imprecise microbevel and works in a very similar fashion. I do find in many chopping scenarios that a microbeveled or convex edge chops easier than a steep flat bevel.

[Matthew N. Masail]

My reason for liking a curved bevel is simply that I feel it allows me good control of the bevel angle when sharpening, I know when I am at 30+-so I also know when I'm a bit less or a bit more. a flat bevel would be impossible (or horribly slow) to alter mid sharpening, but a curved bevel allows me to feel for and adjust that shape of the bevel and the angle of the final edge. I do it every day at work with chisels. it also means I never grind them.

[ken hatch]

Ken, Oh, do I love a nice bevel :D Thanks for the kind words, both were actually finished on the same Nakayama asagi, but the hamaguri bevel will mute the contrast in some lights.

BTW, Have you noticed your Kikuhiromaru to show a damask pattern in the jigane? I found it in mine and I am assuming currently that it shows from a great deal of cold work?

Reinis, thank you! Doesn't take long, I make a flat bevel first then work it a bit more freehand when I want the bevel to become a hamaguri shape.

Brian,

Sorry to take so long to answer....I was in Mexico with MsBubba and the critters trying with great success to find the 20 lbs I'd lost over the last two months. Life isn't fair 2 months to lose, three days to get it back :-). Anyway I hadn't noticed a damask pattern before but then I hadn't looked. When I looked at a couple of the Kikuhiromaro's this afternoon it didn't jump out but maybe the light was wrong or it could be a different finishing stone.

ken

[Brian Holcombe]

Sounds like a great vacation :D

Turns out, I think it's a quality of the old stock chisels (1980's), but I'll find out in a few weeks when some newly made ones arrive. Yours are newer or older?

[Kees Heiden]

That Damaskus pattern, isn't that from the wrought iron used? Wrought iron has a layered structure too, just like Damaskus, it's just not made like that on purpose. So, the pattern is usually not very visible.

[Brian Holcombe]

That's my understanding as well, though I'm curious to know how the wrought is produced, I see some comes from unique sources but not sure how that plays into the effect.

My original guess was quite incorrect, it's my current understanding that evidence of cold work is more likely to be present at the lamination line, however someone with more knowledge of the subject might be able to enlighten me.

[ken hatch]

Sounds like a great vacation :D

Turns out, I think it's a quality of the old stock chisels (1980's), but I'll find out in a few weeks when some newly made ones arrive. Yours are newer or older?

Brian,

New stock. They are a bit of work to prep but once ready the Kikuhiromaro's are very nice. I need more chisels like I need more wives but both Iida Tool and Japan Tool know how to push my buy button. Stu does a pretty good job of button pushing as well. Sure is hard not to whip out the AmEx.

When you think about how Japanese chisels are made and the tradition they come from, they are one of the great bargain of the world as well as works of Art. Some day I will forget about trying to justify them as tools and just buy to own and hold.

ken

[Brian Holcombe]

Lol, I know the feeling.

My old stock Kikuhiromaru were the same way, fairly involved to setup, but once you do they're super easy to maintain. For as hard as these edges are, they're not chippy at all.

I definetly agree, by contrast knives can be incredibly expensive and I'd venture to guess it's not much easier to make a chisel.

[ian maybury]

Been doing a little reading on Kikuhiromaru chisels on the web prompted by this thread (always interested to know more), and ran over related stuff on other brands like Tasai. It's a bit of an expensive minefield to a person coming in cold, isn't it?

Some beautiful stuff (that ultimately tips over into art/collector territory), but equally so many differing types and potentially different applications, and so hard to distinguish what's what in terms of quality - with even counterfeits in the mix too. The sort of territory where if you're buying it likely pays to know your way around...

[ken hatch]

Been doing a little reading on Kikuhiromaru chisels on the web prompted by this thread (always interested to know more), and ran over related stuff on other brands like Tasai. It's a bit of an expensive minefield to a person coming in cold, isn't it?

Some beautiful stuff (that ultimately tips over into art/collector territory), but equally so many differing types and potentially different applications, and so hard to distinguish what's what in terms of quality - with even counterfeits in the mix too. The sort of territory where if you're buying it likely pays to know your way around...

Ian,

you have broken the code. Safest is to find someone you trust to help, not fool proof but......

ken

[Brian Holcombe]

It can be a bit daunting, basically it depends on what kind of work that you do, your tolerance for sharpening and your sharpening methods.

When I decided on Kikuhiromaru I knew I wanted very hard chisels that were easy to sharpen on natural stones. Luckily I also have a stone that loves alloys but it's more aggressive than the one I use for carbon steels and so the edge is ever so slightly less fine. My further refinement of requirements was that I wanted something that would not chip easily. The combination of requirements provides a chisel that is very durable, very hard, easy to sharpen and can provide a very sharp edge.

If you are working very hard woods all the time you may want an alloy, but I know people who do work very hard woods with white steel with great success.

Sometimes the best way is to simply try a variety of brands and see what you lean toward, they have nuances like wine or whisky.

The brands/makers I have tried are; Tasai, Kikuhiromaru, Yamahiro, Koyamaichi, Ouchi. I have a scraping chisel from Takahashi so I don't really count that in the mix. Waiting on some Konobu as well.

If you want striking chisels than next you get to figure out exactly what handle material you prefer :D

[ian maybury]

:) Combining your two posts. Put them together and you end up with the problem of trying to figure out what you really need, then finding a trusted source and communicating that to them. There's a lot to be said for living close to a few people with a lot of experience in the field, as it otherwise risks becoming a bit of a lottery. Failing that it's a learning road i suspect. Trouble is it's a moving target - it seems that it's possible to almost indefinitely go on finding ways in which we would like to further refine our requirement.

I bought a set of Matsumura white steel bench chisels a few years ago based on the usual magazine recommendations, and while the the steel seems pretty damn good by normal standards (but they haven't had heavy use since i've mostly been on shop set up or interrupted by health issues) they needed huge amounts of back flattening work to eliminate most of the effect of a slight curl in the blade. (below as posted once before - funny how a camera sometimes decides a surface is shiny, and sometimes not when they look similar to the eye)

I've thought since that maybe i was picking up some subtle vibes about forums to the effect that they might in retrospect be made to a price (?) and hence less well finished/that maybe a short cut is taken by e.g. grinding of the backs before final tempering/maybe a final step is omitted (again who knows ?) for volume distribution through wholesalers/to permit an extra mark up in the chain while still permitting making the usual noises about hand forging by dedicated master smith xyz?

A set of long handled paring chisels and a couple of fishtails by Koyamaichi in white steel from TfJ last Christmas based on recommendations from here were a nice step up for very similar money - decent steel, more precisely forged and ground, and dead flat backs.

Seems like you're another step up the epcking order again Brian...

323324323325

[Brian Holcombe]

That's nice work Ian!

Koyamaichi, Tasai and Ouchi are very easy to setup in my experience, Kikuhiromaru and Yamahiro have been more work. Yamahiro was the most work in my experience, of the group. The reasoning, in my understanding, is that they're geared toward consumers who would rather be able to determine everything from the get go than to have everything pre-determined for them.

Meaning they would rather work with a slightly curved back knowing that they have more steel to work through before the sides start to thicken, and they would rather grind their own bevel than have one pre-set that they have to change. So I have kikus with two lands flat and the sides are untouched, I will be able to work with them for many years before I start to thicken the sides.

Yamahiro and Kikuhiromaru have had super accurate handles that were very easy to setup. Most I just drove the hoop down, some I had to adjust slightly, before peening the wood.

Tasai sends them with the hoops already set.

None of them were particularly difficult, but some took a bit more fitting work, but your mileage may vary, as they say.

I wouldnt let this become too daunting, of the variety of brands I've used I've been quite happy with all of them. I feel pretty spoiled with everything from the Koyamaichi blue steel parers that Stu had special made for me all way on through the Kikuhiromaru, Tasai and Yamahiro. All awesome, just different.

Also, I dont want to proclaim myself an expert here, far from it, just passing along personal experience.

[ian maybury]

Think i probably ended up taking a bit more off some of the backs to get them flat than i really needed to Brian, but c'est la vie.

I guess another view is that once you get above a certain threshold there may be detail differences, but everything should be functional unless you get a bum example.

:) It's in my case definitely a budget determined matter of using what i have and sticking with it unless real problems emerge...