A little over a year ago now, someone asked if I could make them Seaton chest style chisels. The answer to that was yes. Last year wasn’t a great year, and to be honest, I also got sidetracked experimenting with various steels for plane irons to make sure I wasn’t missing anything. And I started making knives with more intent.
Demands on personal time and some other incidents (getting hit on the turnpike and having a car totaled in an area where rentals were non-existent, rental car places were struggling for staff and then trying to find a decent used car before insurance ceased covering my rental – $300 a day over the counter rate at the time once the negotiated rate expired). I just didn’t get much done other than making a few discoveries.
At the time of this post, I still have only delivered four of the 6 chisels requested. Bad form.
But I’m finally on the last two.
One of the requests was for a large 18th century style chisel, and a picture of one to use as an example (you can google Pavlak’s favorite chisel and land at Fine Woodworking). I think this pattern is likely not historically relevant or correct, though the Seaton book has large firmers, they’re not as long and as bulky as this. This chisel will be in the neighborhood of 1 7/8″ wide, and 9″ below the bolster. And, by the way, I make the historical comment because history often leads us to what was economically useful. But, I am no re-enactor, and not part of the “correct police” bureau.
That said, the size leads to a list of problems – first, I can’t get my favorite chisel steel in 3/8″ thickness, which is what is needed to not have a flat wide tang. would that be the end all? No, but it would look stupid and I would always resent it. Second, I prefer water hardening steels for chisels. O1 (oil-hardening) would be OK, but would have half the toughness of what I chose at same hardness. I doubt anyone would break these, but as a maker, the appeal of a better steel than O1 for chisel fitness is desirable. What did I choose? 80crv2, which is just a plain steel of 0.8% carbon (starrett O1 is 0.9%, and I think Bohler may be 0.95%) with a small amount of chromium and vanadium. This is a “chrome vanadium” steel, which I climb the wall about a little bit when hearing that these aren’t tool steels or they are highly alloyed. In general, there is less alloying in these types of steels than there is in any boutique tools made of O1, let alone A2.
Going back to the toughness comment. Higher toughness allows me to leave this harder and have the same breaking force needed to actually break a tool, or to use a same hardness and have higher toughness. I’ll test edges with a dummy handle, but expect to push hardness to be 62+ so that sharpening is crisp and edge strength is also crisp.
While 80crv2 is popular as a solid choice for knives, I’m not aware of any maker who discloses that they use 80crv2 steel in tools. But, Larrin Thomas states in one of his blogs that it’s often used in tools. I’m guessing those tools would be die forged or European tools, like Pfeil chisels. Someone is using this steel in quantity, though, as it’s far easier for me to find than my beloved 26c3.
Scale – Big
This is a steel that can be forged easily, but I haven’t got a great need to forge it because the information that I can find to refine the grain is based on thermal treatments, and they would all be required after forging. In knife terms, the making is material removal – sawing and abrading. Material removal isn’t trivial because of the size of these. The volume of steel in one is probably more than the volume of steel in a full set of bench chisels. I find it worthwhile to try to get steel a little warm when abrading, but the size thing is there again – the initial work tapering the business end is slow, and it’s smoky and would be a no go in a basement shop no matter what. Fortunately, i have an open door.
If I had a power hammer, I’d forge it to shape just to cut down on the material removal, which was substantial. But I don’t, and it’s not reasonable to put a power hammer in my shop given the floor is shared through the basement. So, I spent about an hour just belt grinding things to size, which stimulates only in the ability to experiment on speeding up material removal process. And wouldn’t day in and day out.
You can see by the scale that compared to a 7/8″ English bench chisel, these are huge. What you can’t see his how thick they are around the shoulder and up. They are over a quarter inch at the shoulder (where the curvature starts) and full stock thickness (3/8″ plus a little) at the tang. The tang will be cleaned up and they’ll be slightly smaller than that when welding a bolster to them and after that. To prevent warp in heat treatment, they need to be relatively flat planes even though the thickness tapers (down to 1/8″ or so at the ends, and the finished version closer to 0.1″).
Further refinement in shape can be done once the steel is fully hard (more grinding, that is), to remove material and add a pleasing curvature to the top.
The steel comes in a micro structure that makes it easier to machine – I’d prefer it didn’t. That structure is coarse spheroidized. This can present a challenge for furnace schedules and oils that are a step too slow quenching steel. I don’t have either of those, so without experimenting, I suspect that it’s not that big of an issue. But, I’m making these once, so they went through another 45 minutes of hand time moving them to a finer spheroidized or pearlite structure. That should result in finer grain, and finer carbides.
The offcuts present a chance to test this theory much faster than the chisels, as the chisels themselves take a long time to heat. They each get 6 heats to do this thermal transformation, and if the terminology is confusing, it’s not that important. Safe to say, the objective is not to make a chisel that’s 2 points softer than it could potentially be. Making things by hand, if you can add something differentiable about the tools, something that a user or you will notice as the user, it’s worth the trouble. In this case, vs. a shorter process, it’s actually a better result, too, and not just akin to sanding to a finer grit on the surface.
I’m interested in seeing how these turn out. O1 would’ve been safe, of course. it would’ve cost more for the steel, but that doesn’t really matter.
I think a wide 19th century style parer would be more sensible in this size and length, but sometimes experimenting is fun.
Interwoven in this discussion is also a matter of details. Rolled annealed material that’s not spheroidized is probably available somewhere. 80crv2 isn’t hard to find, but without experience, I don’t know if I would trust the specs enough to just heat the material a couple of times and quench.
The question of forged or not is probably for another day. For smaller chisels, I always hammer some taper into the steel in three initial heats. It serves two purposes. First, cutting down on grinding, but second, to make sure that if material is offered in a coarse spheroidized condition, that I can get rid of that just as a matter of regular process. If this stuff is done properly, forging doesn’t offer a benefit as none of the steel that I buy comes from unknown mills. These bars are Buderus. To get something of unknown origin would save about $5 per chisel – it’s not worth it.
I’ll report back how they turned out once the job is finished and they have handles on them.
Of Making by Hand with Wood and Steel 