Thread: Chisel forged from rod

by the way, this is kind of sloppy work above - but it's hard to try to do fine work right away without getting bogged down in creating unnecessary permanent steps.

The guillotine thing may not be obvious, but this is what it looks like.

Canadian Guillotine on Etsy

If you can get these parts, you can probably make the guillotine for half or a third of the cost shown here, but it's quite nicely made. It's heavy, the anvils are 2x3/4, so you can hit them with a 4 pound drilling hammer as hard as you can swing it. As long as you have something to put it on (I have a 125 pound hammer).

I don't have the kind of stuff laying around that you need to make something like this for any less if going out and buying components. I'd not be surprised if the guy making them can make one an hour, and good for him.

I was wrong - when I went looking for a 6 pound cross pein hammer, there definitely are boutique suppliers of hammers and such offering $300 hammers without giving enough information to know why they're $300. But there are a whole lot of blacksmiths and machine shop guys who are probably hobby blacksmiths turning out stuff for a really reasonable price.

i wish a 250 pound anvil could still be had reasonable, but that ship has sailed if you're picky and you want a really good one that's flat with corners that aren't all broken off.

one last picture here - plenty of talk is already had here about the ease of doing -but importance of doing it - thermal cycles applied properly to re-establish grain boundaries after forging and to do it in sizes as small as possible.

That procedure is done by one high heat and air cool to normalize and then five or so heats before heat treatment to the nonmagnetic transition only and cooling to strong magnetism and back and forth and so on. With an induction forge, you can do that with pretty good care and evennness (no accidental overheating of corners) in a few minutes.

But also important are aspects lost to time. To really make a balanced strong chisel, some level of curvature needs to be had on the top. The tang will be strong, and the first several inches of the chisel will not be overly flat where you don't need to have bulk for strength.

Compare this to something like blue spruce, which is just cheap flat stock stuffed in a handle for a lot of the range. I think that's fine for a shop chisel, but it's bizarre for chisels that cost $100 or more each.

https://ofhandmaking.files.wordpress...3055751358.jpg

I did not come upon this by reading about it, and the picture isn't as good as it should be, but the chisel is .14 inch at the bevel end, .175 in the middle and .27 at the tang. I found a preference for this and it just looks better.

And then I later found nicholson's description of a firmer, which is just a general definition of a chisel meant to form shapes in work while a finer chisel does refinement (a delicate parer, for example). Nicholson's description of a firmer matches what I found I liked by trial and error. Stiff strong shoulders and the right spring in a chisel (or lack of) without the chisel being heavy. The nuance of the curvature looking nice and more natural is just a bonus.

Originally Posted by D.W.

by the way, this is kind of sloppy work above - but it's hard to try to do fine work right away without getting bogged down in creating unnecessary permanent steps.

That reminds me of a mantra often dispensed by a boss that I had years ago was... "Don't polish the wings until you have done a test flight". He was a metallurgist with a background in aviation, so no surprises where that came from.

I'm, to a fault, an inveterate exponent of the prototype with some of my prototypes still in regular use twenty year later and still not making it up to the top of the list of things to be made again, but properly this time. There must be a more balanced approach, but I have been too busy doing new stuff to take the time to find it...

Originally Posted by NeilS

That reminds me of a mantra often dispensed by a boss that I had years ago was... "Don't polish the wings until you have done a test flight". He was a metallurgist with a background in aviation, so no surprises where that came from.

I'm, to a fault, an inveterate exponent of the prototype with some of my prototypes still in regular use twenty year later and still not making it up to the top of the list of things to be made again, but properly this time. There must be a more balanced approach, but I have been too busy doing new stuff to take the time to find it...

I like that saying! it depends on whether the point is making the tool, or making something to get something else done when you don't feel like focusing on the tool. I've made planes that take 1 hour (open sided drawer grooving planes), and still use them. Some of them work so well that I am attached to them and don't want to make a prettier version that would potentially work 5% better.

Making only perfect things also squashes experimenting and to some extent is a distraction from making something that works really well (for example, making weird handles with a heavily sanded and burnished bright finish only to step back and think "it's not as comfortable as it should be").

I've got one even worse from these trials:
https://ofhandmaking.files.wordpress...3095942433.jpg

I think I made 3 W2 irons last year. The W2 here is just designated as such, and I think it would fit in the W1 designation, but the retailer who special ordered it - a 0.95% carbon steel with an addition of vanadium, which perhaps the vanadium is just above spec at 0.25% or something - to protect overzealous forge heating grain growers...something not uncommon among knife makers.

The rod I got from mcmaster carr here is W1 spec, but no clue on vanadium - I don't really need it for something that doesn't take much heat to get full hardness, but I want to see what a plane iron will be like when it's pretty much the identical alloy but it's hammered from rod. So this little scrap is that. Hand hammered and then freehand ground (I don't have machine tools, just belt grinders, and nothing to speak of with a "good platen"). While hammering out the rod to this level of flatness, I got a little tired, figured it would be interesting to find out at what point, I'm using too much heat and the break is a spot where I pushed the temp further and further (knowingly well above the forging range) and it cracked. So it's going to have a brief life. If I had to, I could hammer out another one that's full length now (hope not to) - the exercise is more to see what the edge looks like once it wears and whether or not it looks better than the bar stock W2 that was just heated. Or at least as good. If it does, then I know if perhaps a burning desire arises to make a tapered iron, I can once in a while hand hammer one out of rod.

It would be nice to break this also and look at the grain, but I guess that will depend on how well it works. If it's nice to use, then that will be a little harder to tolerate just wasting it to confirm the carbide and grain pattern is fine in a break.

If the iron shows flaws, then I'll know that there are problems to solve, and that's fine. Maybe it will be the case that it's not a method to use, but there's only one way to find out. it came out of the first temper at 64.5 hardness 67/68 out of the quench, which is a little concerning, but it does at least suggest that I didn't decarb it despite really pushing the heat level to make forging a little easier. High heat, but with an induction forge, the steel gets hot really fast rather than sitting at that bleeding carbon out into a forge for a long time.

if the higher hardness is due to bloated grain, it will show its behavior by chipping little bits too easily. Seen that before.

Interesting about induction heat treating. If you don't mind me asking, what sort of setup are you using? Do you think any of the 120v systems have enough power density? I have seen systems up to 3,000 watts marketed as 120v compatible, but I doubt most circuits could stand more than 1500w.

I'm using basically a 7.5kw induction forge that touts itself as 15kw. It may be that the magnetic impulse is intermittent and actually at 15k, I don't know. Mine runs in a 40 amp 240 circuit, so it takes in about as much as a relatively strong 220V welder.

There are two things going on with an induction forge - one is how much current and the other is at what frequency. The higher the frequency, the better for thin items. This machine seems to be keyed for material about 1/4th to 1/2 inch thick. if your material is thinner, it won't get to full temperature as the eddy currents that occur once the magnetic forces get into the steel will run into each other and cancel out. This sounds like theoretical hocum, but what it plays out as is even though i have a custom made coil that I made to handle thinner irons, they will just get to the point of being hardenable for plain steels if such an iron is below .1". so I was struggling with this one to get enough heat into it evenly and should've just preheated it and finished it in a forge.

When something is thick enough, like a typical 1800s chisel profile that's about .1-.12", it is easier to chase high hardness with the induction forge by bumping the temp up quickly at the tail of the heat and then quenching. As in, I see less grain growth doing it vs. the forge.

All that said, do I think you'd find a 110V 3kw (that really would draw 1200-1500w continuous) induction heater that would do what you want with tools? No.

For heating work to forge, I wouldn't mind having twice the power that I have, but machines above the 15kw rating are three phase high voltage power.

For me to heat an inch of rod to about 2500 degrees assuming the rod is 7/8" inch diameter is probably a 1 minute heat. Where a propane forge would be more handy is if you want to heat something that large and a long length of it at once. it'd be hard to keep such a length continuously hot. To do a 5 or 6 inch length of a chisel is no problem though - just move it back and forth through the coil and the whole thing will get to an even color temperature and plenty hot.

if I would hold a 7/8" rod in a 1.5" round coil, it would eventually burn and the end would fall off (that would be a problem!). if I had a 1" coil and had 3/4" rod, it would get hot faster because the magnetic force decays exponentially. the closer the item can be to the coil without touching metal and grounding the machine (it stops when that happens), the more of the magnetic field end up in the piece.

Which leads to one possible last question - what happens if you use a higher frequency machine to heat steel that's too thick. I was heating 20mm rod earlier today and hammering it over lunch.

What happens is the outer part of the rod heats first (and fast if it's close to the coil) but the center doesn't take that long to catch up since the heat inside the outer hot ring doesn't have anywhere to go but toward the center.

All in all, it's a fantastic machine. if you have a welder and a water cooler, it will run with this machine, and the machine itself with an extra length of tubing to make a second coil in a different shape was something like $1200.

Of course, you need 40 amps of 240 power and 6 gauge wire or so to handle it. My panel is in the garage near the door, so I have kind of a sweetheart situation as far as where the forge is, a short run of expensive heavy wire and the ability to run a fan and blow stinky quench smoke out of the door.

I don't have burning hands and face from the intense top burner propane forge, though, nor the hassle of chasing propane all the time.

https://ofhandmaking.files.wordpress...-carbides2.jpg

So this is a very highly magnified picture of the edge planing. The scratches showing behind the edge are probably middle stone scratches, and some may still have gotten to the edge deeper than the finish stone and buff.

But, the way it behaves so far reminds me of W2 almost exactly.

This steel has at least 0.95% carbon which would leave visible carbides, but it has also been heated plenty of times to hammer the iron out, so I don't know the exact reason no carbides at all show up other than it may be a tenth lower or so in carbon and just not have enough to bust out of solution and make carbides bigger than a micron so they can be seen.

It's got some edge life left and I don't want to break it off because of that, but I may. There's no other way to see the size of the grain vs. the size of the carbides except a nitric acid etch, and I don't want to get into that. I'll know what I'm seeing when snapping samples and microscoping their size.

W2 was nice, but I didn't like it as much as pushed 80crv2 - it didn't wear as sweetly - and not as much as really good quality O1, which also wears sweetly and evenly.

I gave this another temper today at 410F which brings the hardness closer to 63. It would be possible to have a really good quench and have that hardness with the steel, but it still seems a point high which I don't like. Higher hardness than expected at a temper is just too often associated with zero retained austenite or increased grain size. Both of those lead to a lower toughness edge, and toughness isn't king with plane irons but you still need to have "enough" toughness.

the little vertical lines in the picture running perpendicular to the edge are just oil. it's so hard to get all of it off for a picture, but also illuminating in terms of why it's so uncommon to see rust on tools used by oilstone sharpeners.

I remember something about recent W2 being formulated/marketed towards knife folks who wanted extra-shallow hardening and vanadium carbides for hamon formation. It could just be that those carbides make an edge that's pretty but doesn't behave as nicely in actual use.

Anyway, I've got this hankering to give the whole re-hardening chisels experiment another go... But this time, I would run through several grain reduction cycles prior to hardening.

Originally Posted by truckjohn

I remember something about recent W2 being formulated/marketed towards knife folks who wanted extra-shallow hardening and vanadium carbides for hamon formation. It could just be that those carbides make an edge that's pretty but doesn't behave as nicely in actual use.

Anyway, I've got this hankering to give the whole re-hardening chisels experiment another go... But this time, I would run through several grain reduction cycles prior to hardening.

Running thermal cycles before quenching is a very good idea. Larrin discusses issues with grain size getting so small that hardening is problematic, but I think with plain steels and a fast quench, it's not going to be an issue for us. Rather, it's more of a problem for someone with a set furnace schedule and more "kind and easy" quench. The last brief heat can be increased if it's a matter of seconds, and the quench speed increased, and then I don't see any difference in hardness. Without thermal cycling, though, it's easy to blow up grain and then have no remedy for it.

For W2, the vanadium is just a trace - the carbides can't really be found visually that I can see, but you can find iron carbides. Whatever remains of the vanadium sits at the grain boundaries and impedes growth to an extent. Once you get above 0.5% or so, you start to see bigger dedicated vanadium carbides. And everyone hates them, it seems, given the favorability (or lack of) of cru forge V.

W2 is shorted on chromium and manganese in sum by quite a lot. 1084 has somewhere around 0.7-0.8% manganese and I think the last melt of W2 that I got has 0.22% and another trace of chromium. It benefits from a bit of a hot lunch right before quench (but like seconds, not minutes) and the vanadium is a big help if you have a five second mental lapse.

Thanks for pointing out the hamon - I forgot who the target market was. Both it and the right version of W1 can get a crisp hamon since anything impeding hardenability at all (clay) will leave a stark line.

My luck with W2 for plane irons was good, though - all iterations hardened fine, but all were also 0.1" or thinner...now I recall we discussed this briefly on here before. I think a fat chisel or a tapered plane iron made out of solid would have no chance. The balance tips quickly and you can't cheat it. it'd make an interesting fat spine knife, though - you could chase high hardness at the edge and the spine would never fully harden and the knife would be pretty difficult to break.