I use draw knives frequently in wood working. Sometimes several hours per day, day in day out year after year.I can often go more than a year without sharpening my draw knife and I am cutting on some of the hardest woods in the world. One time I was telling a student that I preferred a not so sharp draw knife, and I ran my finger over the edge. It was razor sharp and cut me quickly. They seem to hold an edge forever. Most of my draw knives were likely made in the 1940’s and possibly earlier. I am able to sharpen them with a good quality file fairly easily. Nothing I buy today will hold a candle to these old knives. I can seldom go a week without sharpening. I know they are high carbon because they are somewhat rust resistant. What was the difference in the old knives? I have a feeling that tempering and heat treating play a big part in this.
Martensite?
This article about “super hard high speed steels” goes into some of the additives like vanadium for high wear resistance and high carbon and cobalt for hardness; e.g. Maxamet has 2.15% carbon, 4.75% chromium, 13% tungsten, 6% vanadium, and 10% cobalt, plus other components. That one is not in “old” knives, but you can see some graphs concerning obtaining high speed steel by adding cobalt and optimizing the carbon content. M42 has 1.1% carbon, 3.75% chromium, 1.75% tungsten, 9.5% molybdenum, 1.15% vanadium, and 8% cobalt. See also Tool steel - Wikipedia, e.g. D2 with 1.5% carbon and 11-13% chromium. I met a machinist who made some knives out of D2.
HSS is a possibility. Some people claim it makes superior lathe turning chisels. Lathe turning is a high wear activity, needing tools that hold an edge well and hold up under repeated sharpening.
Funny you should mention 40s: yesterday, I saw this video comparing armor plate of the era with some more modern. I don’t know now it translates to blades but it demonstrates the state of the art for this particular steel property.
The difference between WW2 armor and modern armor. : EngineeringPorn
I understand this whole “knife-steel” is a 2 step process.
1.) the kind of steel used … and…
2.) the hardening process per sé …
so you can have a somewhat “run of the mill” type of steel, which I assume holds true for the 1940ies steel you have in your knife
… and if done right that mediocre (by today’s standards) steel can be hardened to standards that would even today be a good value … so there is def. a “knowledge” component in there concerning the hardening of the steel.
Having said that, high carbon steel is notorious for a possible wicked-sharp edge (that holds reasonably long and can be re-sharpened in seconds) - my lowly Opinel No10 is testament to that!
Another point - not in the scope of your Q - is “Blade geometry” … and that is imho - even more important than the steel used.
So my guess is that your vintage draw-knife has a decent carbon-steel, hardened very well by a reputable brand (when there was time to do things right) - but has a hugely specific blade geometry for the job at hand
Over the last 30+ years, I’ve worked with a lot of drawknives. I’ve done this work with people that have been using them since the 60s. It is a very common tool for wooden boats.
We have collectively found that the old drawknives are far superior to what you can buy today. I know I found a lot of 3 at an auction for $5 each and our expert sharpener restored a beautiful edge to them that is easy to maintain even for someone of mediocre sharpening talents like myself.
From what I have seen, it isn’t a difference in angle, but maybe blade geometry means something else?
The sharpener expert and one of the old timers insisted it was the grade of steel used as late as the 60s but no longer for drawknives. We found even a good quality one from Rockler was pretty inferior to the old drawknives.
BTW, for clarification, this is what the OP and I are talking about:
I’ve talked about them semi-often over the years in woodworking and wooden boat threads.
I held off replying until factual answers were presented as mine is pretty much an anecdotal reply.
What’s the honing angle on the edge? A more slender ground edge will tend to lose its edge more quickly than a more wedge-like grind but a steeper grind requires more effort to push it through the material being cut.
Given that the tool is used with more force applied than, say a kitchen knife or even something for wood like a Swedish carving knife, it might have a steeper bevel.
Yes, that is accurate. But both the new and old blades had the same bevel as far as I can recall. I don’t have any new ones left. I gave my one new one away and kept 2 of the old ones including my favorite.
But that does explain why they keep sharp for so much work and are easy to resharpen.
I mean we literally carved boat spars and oars with them and probably do a maintenance sharpening maybe twice for the large spar like a boom and once for an oar.
The bevel looks to be about 30 degrees. Maybe 22.5. The bevel is about double the thickness
I buy them on e bay all the time for about $20.00 I give them to students or people I am teaching. The new one are not nearly as good as the old ones. I have to sharpen them more frequently and I can’t usually sharpen them with a file like I do the old ones. They seem to be a harder steel but don’t hold an edge as well.
My first job where I punched a time clock was making masts for sail boats. I primarily used a spokeshave and a block plane.
chisel grind?
Very cool. The one mast I worked on was whittle down from basically a telephone pole. We used chainsaw, power planers and belt sanders.
But most of what I did was smaller for a 26’ sprit rig 2 masted garvey.
We carved many oars (sweeps) and a few spars for the Garvey. Most of the shaping was by drawknife. Some spokeshave towards the end.
Single bevel, chisel grind. Very steep angle.
The masts I worked on were laminated spruce. Small masts for small racing boats. I think they were about 28 ft long. We would rough them out on a shaper and then the hand work.
I’m curious as to which Rockler draw knife the OP has been using. Rockler don’t make these tools, but sell those made by at least 4 different manufacturers. One cheaper knife claims RHC 30 hardness, which is not exactly hard. Veritas and others claim 61 and similar which is vastly harder. Rockler sell a flexible draw knife as well. Flexibility and hardness are not a happy pairing without significant effort.
Really nice tools involve a significant amount of nuance in choice of steel and the precise heat treatment involved. Ideally you want a resilient flexible base with an edge that is hardened and tempered to take and retain a good edge without brittleness. The circumstances the tool is used in affect these choices.
Materials like high speed steel are not what you want. It is designed to retain hardness when run hot (ie when cutting metal at speed) and is both too brittle for a hand tool and the heat resistant behaviour is of no value. Tool steel is designed to be worked easily before heat treatment, but is unworkable once treated until annealed again. A draw knife is going to be an interesting set of competing problems. Pressure on both ends of the knife will be a significant danger for snapping a hardened steel tool. There is probably no one right answer.
If the older knives are no longer available after WWII they may have been made from crucible steel. Modern steel making eliminated nearly every source of the old slow steel making technique. Maybe some English chisel companies like Marples still produce it somehow. The metal may be laminated to softer metal to allow it to flex, especially where attached to the handles. It would certainly have a chisel grind and could be reground continuously that way. I’d imagine draw knifes would out last bench chisels or similar tools like a fro because it would never be struck with a hammer and only used parallel to the grain.
I don’t think I mentioned rockler but I have used rockler knives or knives that I have purchased at rockler I’ll put it that way I think one of them was a flexible knife. They were sharp when I purchased them but they didn’t hold their eggs as well as the old knives
Mea culpa. I was confusing various responses.
I guess it would be interesting to be able to compare various brands. There is certainly no reason for any manufacturer to produce anything of lower quality than before other than cheaping out.
I just sanded the rust off of one of my newer ones. It is a Greenlee, made in Rockford Illinois. .