I figure most folks here have seen how them thar' high-falootin
Japanese chisels have a concave bottom so that, when lapping the
bottom, the only material you have to remove is on the perimeter... not
in the middle. (If not, here's a pic:
Supposing that I wanted to have this nice feature on my existing,
non-stratospherically-priced chisels, does anybody know any relatively
easy way to achieve this? Perhaps with a conical grinding stone mounted
in a drill-press?
Alternatively, does anybody have any tricks for automating the laping
process? I've lapped a few of my chisels but, with the larger ones like
the 1.25"... that's a lot of material to remove. It sure would be nice
if there was some contraption that I could clamp my chisel and stone to
and it would just grind them against each other for an hour while I
went to get a sandwich. Anybody seen something like this, or shall I
design one myself?
for a joiner's chisel you want the face flat, no? - otherwise it would be
really tricky to use sometimes; and when you remove the bur you don't
actually take off any steel from the flat side, you just bend the burr one
way and then the other until it breaks off.
Less material to remove when you hone them, I figure.
Well, if you were in a situation where you couldn't rest both sides of
the chisel against the workpiece (and were too stubborn to just reach
over and grab a narrower chisel), then you'd have problems. However, as
long as both sides of the face are touching the work, it doesn't matter
if the material in the middle of the chisel is flat, coved, or *gone*
True, but I'm trying to resurrect a couple of chisels that I wrecked
early on in my woodworking days. I had some craftsman chisels and
needed to get the milling-machine marks off of the face to get it nice
and flat. "Hey, my belt-sander platen is flat! I'll just hold them
against the sander while it's going!". So, I used my belt sander to
sand the tool marks out. What I discovered too late was that the
sanding belt wanted to ride a little above the platen (on a little
cushion of air), so I was depressing the sanding belt just slightly
when I'd press the chisel face against it (imagine placing your chisel
against a mattress or pillow). This caused there to be more sanding
force against the corners of the chisel and now the chisels have little
"chamfers" or slight round-overs on the corners of the face.
Now, you're probably thinking: "You're trying to salvage a 'crapsman'
chisel? C'mon! Just toss 'em and go buy another set... or go buy some
*real* chisels!". Well, I *did* buy another set and I sharpened them
properly the next time. But I still want to see if I can recover
these... just in case I, someday, come across some *nice* chisels with
the same problem at a yard-sale... or if I someday cause this problem
to some of my nice chisels.
Think of it this way... this month's issue of FWW has an article about
how to recover from joinery goofs. Think of my project as trying to
discover how to easily recover from sharpening goofs.
The blades are hollow-ground to make sharpening easier. An often-asked
question is what to do when the blade is ground down so far that the hollow
reaches the cutting edge. This is actually not a problem - regular
sharpening and honing of the face moves the hollow back so that a straight
edge is automatically maintained. In fact, overenthusiastic sharpening or
grinding of the face by some users enlarges the flat between the edge and
the hollow-ground part of the chisel.
Fri, Sep 1, 2006, 12:04am (EDT+4) email@example.com
(The3rd Earl Of Derby) doth burble:
<snip> This is actually not a problem - regular sharpening and honing ofthe face moves the hollow back so that a straight edge is automatically
maintained. In fact, overenthusiastic sharpening or grinding of the face
by some users enlarges the flat between the edge and the hollow-ground
part of the chisel.
Where did you come up with that little tidbit? I don't think so
Justice was invented by the innocent.
Mercy and lawyers were invented by the guilty.
What do you think the "face" of a chisel is ?
If you have a modern cheap Japanese chisel with a back hollowed by
grinding, then occasional grinding of the _back_ will make this hollow
shallower and will also move its edge away from the cutting edge.
Working on the edge or face of the chisel though won't shift it.
In this discussion, I've been considering the "face" to be the big,
flat side of the chisel that that faces *away* from you when the chisel
is in its retail package. It's the side opposite the one that has the
bevel cut into it. It's the thing that has a hollow in it on Japanese
chisels. It's the thing that sharpening articles tell you is just as
important to have flat and smooth as the bevel.
It appears some people are calling this the "face" and others are
calling it the "back". Norton Abrasives calls it the "back face", of
To avoid any further confusion, I suggest that we drop the usage of
both of those terms and henceforth refer to it as the "snorfl". :)
Agreed.... which I, believe, is what the other poster meant when they
...assuming that, when they said "face", they were referring to the
OK now you are closer than you were when you started. Now all you need to
do is to grind the center of the chisel to meet back with the corners. Use
the fine wheel on your bench grinder. The closer you get to a sharp edge
the greater the risk of getting too hot, have a can of water close by and
quench often. When you get close to your desired geometry cheat a little
and side wheel the chisel. This wil bting you flat. Now you have
reestablished the proper geometry of the chisel and it is almost sharp now
use your stone or diamond lap. Start with the rough and finish with the
fine. In less than 10 minutes you will have a razor sharp chisel.
There is nothing wrong with a Craftsman wood chisel, if it is sharp it will
do the job.
I suppose I'm nit-picking here, but wouldn't this technically shorten
the funtional lifespan of the chisel's back(maybe not in your
lifetime), thus the chisel itself? And I sometimes(well, often) use the
back to orient my stroke. Besides, once the back is polished, you
hardly need to touch it again. You can probably save more time in your
sharpening by hollow grinding the bevels, then only lapping and
polishing the very tip and heel of the bevel, instead of the whole
thing. I think. Tom
Japanese chisels are laminated steel. The back is the harder steel
which is forged with the softer body steel to have that depression.
The Japanese chisels have to have the hollowed back and harder steel
beaten out to form a straight edge as the chisel shortens due to
Your econo-chisels aren't laminated so you won't have the issue with
the harder steel, but you will still have to deal with that depression
which is in a steel that is, on average, harder than the bulk of the
Japanese chisel's body. In other words, a pain.
I'm not sure how much lapping you'd actually have to do once you've
done the initial lapping. You certainly don't have to lap the entire
back every time you sharpen the edge.
It's tough work to make a cheap tool pretend it is an expensive one.
Usually more work than it's worth. You can get used Japanese chisels
on eBay and even some of the new ones are surprisingly reasonably
Old and high quality Japanese chisels are laminated with a thin steel
layer and the hollow is forged in. More recent and cheaper ones are
still laminated, but with a thicker lamination and with the hollow
You tap out the thin lamination ones, you grind out the thick
lamination ones. If you try to tap out a thick lamination one, you'll
Really nasty Japanese chisels are made in China and aren't laminated.
Apart from specialist ones, I've never seen a Japanese-made bench
chisel that wasn't laminated (i.e. they just don't cut that corner in
Those "econo chisels" are Iyori, so they're really pretty decent
quality. Thick laminations, so grind the backs flat as needed.
That makes sense from the physics standpoint, but I've never heard of a
Japanese chisel whose laminatied steel was so thick it couldn't be
tapped out. Can you point me in the direction of some of those
chisels? I want to see what's what.
The econon-chisels was referring to the OP's wish to resurrect some
cheap chisels. He posted the picture of the Iyori chisels as an
example of what he wished to do with the cheap chisels.
Iyoroi. I think David Charlesworth has written on this (he was the
first person I saw who was grinding out his chisels, not tapping them).
Ah - I came into this thread partway through. I see no point in adding
a ground hollow to an existing chisel.
I _might_ try this on a 2" wide slick I use for cleaning up mortices in
larch timber framing. I do sometimes get trouble with resin stickiness
on fresh green larch.
I emailed a temple-builidng acquaintance in Japan about the lamination
thickness and this was his reply:
Thank you for your Q.
Thick steel is bad!
Because steel is thin, I can bend it.
I do it like a bimetal and bend it.
I tap a soft iron and grow volume.
I do not tap steel and do not grow it.
Steel is bent by pushing gently below as a result that soft iron
We must keep big back hollow as newer article.
Because I must tap soft iron.
Imagine Ski bord and figure skating shoose.
Do you understand?
Both of side end mirrored back hollow must become ruler. We call 'ashi'
We love thin women's leg ,don't you?
We must keep thin leg (ASHI).
I will write about them on Ebay guide.
Please wait for a while.
I hate thick steel.
Exported Japanese tools must make thick steel.
Because ,many foreign owners sharpen back many times...
You know ,Steel will be lost!!!
Japanese chiselsmiths change thickness by a customer.
All of my blades are very thin.
Can you see why I love this guy?
Mon, Sep 4, 2006, 5:36am (EDT-3) firstname.lastname@example.org doth ponder:
<sniup> I _might_ try this on a 2" wide slick I use for cleaning upmortices in larch timber framing. I do sometimes get trouble with resin
stickiness on fresh green larch.
Hmm, at first thought I would think maybe dipping the slick in
mineral oil, kerosene, recycled cooking oil, alcohol (hopefully not the
drinking kind), or something might do the trick.
On the other hand, I also wonder if cutting a slot clear thru the
slick would work - at the risk of ruining the slick, of course - but it
is your slick, so it's not my risk. LOL
Might want to consider making one, or a few, for test purposes. I
betcha the old timey shipbuilders had the same problem, wonder how they
dealt with it.
My shop, my rules.
First off unless you have been using a wood chisel as a nail cutter or a
stone chipper then lapping should be relativly easy, and if the chisel has
been abused, dressing it with a grinder or a belt sander is the quick way to
get close enough.
Once the angle has been established it is really no big deal to bring out a
razor sharp edge. I like the diamond stones they have out now, they cut
They do make a chisel sharpening guide, but I have never found a need for
Once I get the edge sharp enough to shave hairs off my arm, I will take it
to the buffer and polish it. I am not sure that it makes it cut any better
but it sure looks nice.
I don't do that for looks, I do it to save time. Takes longer to
chase the wire edge than to simply knock it off with two passes
over a wheel loaded with green compound. It also makes the
chisel almost immune to rusting. Not sure if that's from the polished
surface or if it's because the compound leaves a light grease film.
Do you rake your wheel? I don't, and its stropping action
seems to improve with each use.
At the shop I worked at we only had one buff wheel and that saw a variety of
materials and compounds so it was cleared from time to time especially if I
was buffing something with progressively finer compounds.
I suspect the wax base in the buffing compound is what is inhibiting the
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