what chisel shape would you choose..

Edge holding

David Weaver

I managed to snap a picture of the rosewood handled 5/8th chisel after vigorous chopping of cherry. 6 cubic inches and the edge does have some bits and pieces of failure, but they're minimal (nothing big enough to leave lines) and the strange thing is that it continues to shave hair a little bit.

There are spots here and there just a little deeper than this, but nothing bigger than a thousandth or so deep.

The failure is very uniform edge to edge (the unicorn test edges looked better than this on maple, but the chisel edge was wider and the volume chopped was a lot less).

Re: what chisel shape would you choose..

Wiley Horne

Hi David,

They’re looking great! I definitely prefer the fishtail shape, for the reason that it gives such good visibility as to exactly where the corners are cutting.

No opinion on the longitudinal curvature. I am interested in your observation that a little concavity (on the back side) resists diving. It has always seemed to me that a dead flat chisel back will not avert diving—you have to do that by guidance and by taking multiple thin slices.

Wiley

Re: what chisel shape would you choose..

Steve Voigt

I guess I'd rather have a flat back, but it's hard to say without more data.

That bolster in the second pic is just porn. Zoinks.

Re: what chisel shape would you choose..

Warren in Lancaster, PA

I have been using chisels that are about 200 years old. Usually the bolsters are somewhat larger than what you are making, and the octagonal handle tapers to within 1/32 or so of the bolster dimension. Occasionally it appears that they filed the bolster flush after the handle is on. On narrower chisels the bolster is smaller, the handles are somewhat smaller and the taper is more pronounced.

In the 17th century the taper in width is quite pronounced, but during the 18th century the taper gradually diminished and by the mid 19th century had disappeared. I like a little bit of taper.

The taper in thickness is pretty extreme; the thickness just before the bolster can be four times the thickness at the bevel. These chisels generally don't have side bevels.

I am used to tangs that diminish to a sharper point than what you show.

I have watched a blacksmith make a bolster. They take a little worm of iron and bend it around the shank and then forge weld it to the chisel. Then they work it with the hammer and finally refine with a file.

Re: what chisel shape would you choose..

TomD

As mentioned a while back, the offset back, as seen on Japanese chisels and other designs, is great for the reasons you mention. I don't see the curvature as an advantage, but I have not experimented with it, and it does get you to a place where you do not even feel tempted to flatten the back, and that can be a good way to go. Double bevel chisels are surprisingly useful, also.

Re: what chisel shape would you choose..

Derek Cohen (in Perth, Australia)

David, in a wide chisel, I want the back to be flat since it is likely to be used against a guide or need to be directional ...

It is not critical that the sides are parallel, but some cuts will benefit from being able to be guided by the sides.

More important is the flat back. As Tom mentioned, Japanese slicks have a slight offset to the handle. This is not enough to be noticed when pushing the chisel (does not alter the vector), but it lifts the knuckles/handle off the bench or work piece.

Regards from Perth

Derek

Re: what chisel shape would you choose..

David Weaver

The diving thing is interesting - it's obviously keyed to a certain thickness or angle (Since we adjust correction between mallet strikes with a straight chisel and how much correction depends on how deep the cut, how thick the cut and how hard we're going to hit a chisel. Heavier means more dive).

The rounded chisels will dive a bit if you allow them, but the shape partially corrects, or feels to and it's a bit more thoughtless and less fiddling. It'd never fly with modern woodworkers who watch videos re: paring blocks and such, though.

But it's interesting to experiment with. It's also a *very* natural shape to forge, just a little bit of curvature.

Re: what chisel shape would you choose..

David Weaver

I have a couple of older chisels, but not sure that I have any old enough to have been pre-bolster (at least none that have been left alone).

I recall george mentioning that at CW, they were experimenting for ways to add a bolster. It would seem to me that the least difficult way to do it would be with wrought iron chisels and a wrought iron bead/wire laid around the tang as you mention. It'd would be lovely to hammer it in integrally by thinning the tang on both sides of the bolster, but I see that leaving more filing. Perhaps on an anvil with a really sharp corner you could do something like that accurately.

I have no concept of what it's like to forge super hot when metal moves easily, nor to forge something that moves more easily like iron. I"m hammering the tool steel around critical and in terms of how much it moves, very little. If I overheated the steel near the tang to try to forge weld something on, it probably wouldn't be a big deal, but forging the bolster to shape at this point and shrinking it on is a little easier to be sure that I won't have a bad weld (I don't think high carbon steel forge welds that well to mild steel).

I leave the tips a bit blunt just because I'm not filing them all the way tapered out. I'm starting with the file tang which is a bit thin for my taste, so I can't (without shifting further down the file) make the tang taller and steeper and squared to a point. It's mostly the shape of the tang that came with the file perhaps hammered in from the sides a little bit to build up the height a little - but toward the very end it's just filed off.

Am i correct that most of your chisels are laminated, or are the ones that taper that drastically all cast steel?

Re: what chisel shape would you choose..

Jerome

> what chisel shape would you choose if you could ...

I enjoy the short and thick format of Japanese chisels for small sizes (say 10th of half an inch) on small work, which are common in furniture and tools making.

My hands is close to the edge, the thickness makes them stable in a mortise, etc. It’s a "safe" feeling.

I don’t use my mortise chisels as much as I should. They are old sorby’s and Peugeot frères, tapered in every dimensions, very easily sharpened on all front edges. They don’t feel like precision tools though, with huge bolsters and handles. I use them on oak. I don’t bother on chestnut, beech ...

For western bench chisels, I appreciate a flat back and parallel sides, mostly as a reliable reference. I don’t use dedicated paring chisels, so there is that. I prefer them rather thick. As a consequence of the lockdown, I don’t have my small Japanese chisels and I have used my 5 and 10mm bench chisels to cut mortises ... cringe.

My favorites are flat, plain Jane Marples

Jim Matthews

Those pre-buyout Marples are dead flat, and nearly featureless.

My Barr framing chisel gets me out of more "interesting" jams and has a belly.

This means I can cut only where I want if there's no squared "land" to register off.

This works like a spokeshave, in reverse.

Curiously, this curve gets me to a tenon of uniform thickness where my flat chisels lead me to taper or make a trapezoid cross section tenon.

Re: what chisel shape would you choose..

Warren in Lancaster, PA

I don't know what you mean by "pre-bolster" chisels. Nova Zembla chisels (1596) have bolsters as do Roman chisels and Bronze age chisels.

My chisels are mostly not laminated. At one time the smiths had trouble welding Cast Steel; I don't know how long this was a factor.

Here are some chisels from 1816:

Re: what chisel shape would you choose..

David Weaver

sorry, I mean pre-ferrule chisel, not pre bolster. I'm assuming that the bolster being forged was something doable long before production of thin tube steel was common.

Thanks for the picture - that's generally the style of chisel I'm looking to make - some with bevels, some without. Since I have limited desire to do significant moving of metal (in blacksmithing terms) and more shaping, it depends more on the starting stock (half round files make for a great starting point for beveled chisels, and flat chisels and flat stock for thinner with less of a bevel.

I gather from what I could glean from George (without him telling me directly one thing or another) that one of the issues for smiths working now is getting really clean wrought, which makes hand forge welding iron to steel more difficult. He'd mentioned more than once (including publicly on sawmill creek) that the blacksmiths preferred 1070 or something similar. I don't know if they just use what larry provides when they use larry's planes - I'm guessing so.

George has made his share of chisels and carving tools, but not for anyones' consumption but his own as far as I know. Strangely, in a decade of talking to george, the topic has never come up and I guessed into shrinking bolsters on tangs rather than forgoing them (an aesthetic that I don't like *at all*, to see a modern chisel with no bolster and a really heavy ferrule to make up for it). George mentioned something similar - filing close to size and then driving a hot ferrule tight and allowing it to shrink to a tang.

I'm waiting for the punchline, as making really pleasant chisels has been a bit too easy so far and getting a little bit more tidy and really finely finished without much extra effort isn't far away.

The ability to steer in a level cut...

David Weaver

one of my early sets of japanese chisels (bought off of ebay) had convex backs. I thought it was a fault of low quality until figuring out that they can be controlled so that they don't dive past a mark, but still cut just as well.

There's too much literature out there already from wearing and others describing setting up paring jigs, etc, that need a parallel sided chisel and one dead flat on the back to convince many people to swim against the current, though.

Just for fun, David *LINK*

Bruce, a MN Galoot

Take a look at Torbjörn Åhman make a laminated chisel


Blacksmith chisel making

Re: Just for fun, David

Warren in Lancaster, PA

I watched the whole video. It was very weird to see a blacksmith replicate a drop forged chisel with hand methods. These chisels are designed around the drop forging process; hand methods are more versatile. Its like making Mcdonalds hambergers at home or making biscuits for biscuit joinery in a hand tool shop.

I guess old leaf springs are awfully cheap, but if you are going to make a chisel by hand, why not use a steel that was designed for edge tools? I have a blacksmith friend here in Pennsylvania whom I approached about making a chisel a decade ago. When I told him I didn't want leaf spring steel he said "you don't know anything about steel".

way beyond what I'll ever do...

David Weaver

...with heat and an anvil. It reminds me of a berg chisel, and I'm guessing by the guy's name that he's scandinavian of some sort.

I like that he took the time to really finish the chisel nicely - there are a lot of videos of socket or heavier chisels where the chisels are left really really fat and rough.

Re: Just for fun, David

David Weaver

I read the same thing years ago when I first thought about making knives, that high carbon steel isn't tough enough to make a good knife.

It must be based on who the customers are (people banging knives through 2x4s and into the sides of 55 gallon drums).

Files make such a good chisel, though, and it takes so little skill to make them much better than just grinding part of the file away.

I'd like to see the smith in this video make all steel tang chisels, but I don't know anything about his channel and with the number of views that he gets, I'd guess that he makes a variety of stuff to draw views (getting stuck on the details of anything is a way to shed viewers fast).

Re: Just for fun, David

Bruce, a MN Galoot

OCLS in knife making stands for old Chevy leaf spring. Leaf spring steel is, at least in Chevys, 5160 and is favorably regarded among knife makers.

Re: way beyond what I'll ever do...

Bruce, a MN Galoot

Torbjörn Åhman is Norwegian. I was green with envy over his slab of Masur birch..

I recall..

David Weaver

..for a giggle, I went out and looked at "5160 vs. 1095" and I can't say I found too much other than that 5160 does get good press for big knives.

The knife world is filled with a lot of guys who will write a blog post with definitive conclusions (some of them are right, but some of them are way off). One said that if you were in a survival situation and had to have a knife that didn't break and sharpened easier on a rock, you'd pick 5160

If I had the inclination to make good videos, I would make a spoof knife video called the post-2k knife survival test and it would have the following stations:

* cutting 5 feet of tape off of packing and cleaning the residue off

* cutting five boxes into pieces small enough to go into a recycle bin as fast as possible

* sprinting to a station where kids were opening presents and cutting all of the packaging away from the toys - the stuff that seems less designed to be packing, and more toy stabilization/retention so that they can ship a finished toy from china in a box and not worry about it rolling around (you guys with kids or grandkids know what I'm talking about)

* a station with a campfire and 4 kids screaming "I don't have a stick for my marshmallows....I'm not putting marshmallows on bark, either!!"

Re: Just for fun, David

Warren in Lancaster, PA

5160 steel has a carbon content of 0.6 percent, barely a high carbon steel. I don't think it hardens in the range we are used to using. Chrome content is 0.8, Manganese is 0.9. I cannot imagine wanting a knife made of this material and I don't think many are. I have used low chrome knives for more than 50 years.

practical vs. the big knife crowd

David Weaver

you're thinking of slicing things and doing "normal" tasks with a knife.

A nice carbon steel knife made of 1095 with a thin blade is cheap and not something a "bladesmith" could compete with.

Making a 9 inch fixed blade knife that can hatchet 2x4s is what seems to be the draw, and they're necessarily tempered softer than what we'd use.

I'm a bit suspicious of the reputation of 1095 being brittle if it's kept at low hardness, but 5160 wouldn't last well if it was hardened to 61 and used for edge holding purposes.

There's a whole lot of scuttle about 1095 and W1 cracking, too, but I've never had any issue with it in an oil that flows well (vs. trying to get away with hardening it in water). Soy oil is probably one of the worst oils for human consumption (high smoke point, flows well, probably very little natural about it), but it makes a great quench for 1095.

1095 is harder to hammer and shape, too, especially warm shaping (vs. hot work).

5160 vs. 1095

David Weaver

5160 is often recommended for knives due to the fact that it can take impact damage and probably bend further than a high hardness 1095 steel.

For slicing with a knife or chiseling, it's pretty poor. Actually, i'm not sure what task it would be better for in terms of day to day use (in the kitchen) unless one was making a garden knife to hack things or making a soft knife to be steeled (1095 would probably still be better there).

The world of blacksmithed knives is a whole different one vs. chefs knives or woodworking tools (the japanese tend to make thin knives and with steels of 1% carbon on up from there, and the older solingen knives were made of 1% carbon stainless - I haven't seen older carbon steel offerings, but the razors have always been similar steel to better knives because of the edge holding and lack of intentional abuse).

Not to mention things like "coarse sharpening" that are popular with knife folks.