making a marking knife

most likely not...

marketymarkmark

>carbide blades tend to be mild steel with carbide tips...not always, but most likely. since it's the carbide that does the cutting, there's no need for good, high-carbon steel on the body of the blade...and mild steel won't hold an edge.

non-carbide blades would make a good knife because they're made of high carbon steel.

if you want to be sure...

marketymarkmark

>i don't know what kind of resources or experience you have, but there are two ways to test whether the steel will make a suitable blade.

1) heat a piece to red-hot, to the point where a magnet won't stick to it, and then plunge it in oil. (if it's a small piece you can use water, but don't use water when you're making the actual blade.) put it in a vice and whack it with a hammer. if it shatters or breaks off like glass, you have suitable knife-making steel. if it bends, forget it.

2) run it over a grinder or belt sander. high carbon steel will give you a shower of complicated sparks. mild steel will throw off sparks that look like a straight line that forks out at the end. higher carbon steel will branch off and fork all over the place. (if you've never done this before, you'll need to have something to compare it to to get a good visual of what i mean...you might try running an old chisel or knife on the grinder and compare that to a piece of mild steel to get an idea of what the sparks should look like.)

I tried your suggestion

Bruce, a MN Galoot

>and it turns out that the plate produces sparks not quite as complicated as those from an old file. I compared it to a piece of known mild steel, and it's much closer to the file than the mild.

Thanks. The saw plate might not be good for fine knifemaking, but it'll sure work for a marking knife.

Bruce

Re: I tried your suggestion

William Duffield on the Cohansey

>A marking knife, if used in a manner that does not change the geometry of your bevels, squares and dovetail gauges (^::^(, doesn't get a lot of wear. While one made of high carbon tool steel works better, more mild mannered steels do OK. I made a really delicate one from a busted jigsaw blade, and it works fine. Even one made from a circular saw blade should serve you well, as they are usually made from good quality steel, even if not hardened to the max. If you have anything left over from the one you salvaged, you should be able to make use of it for scraper plane blades and scratch stocks.

Re: I tried your suggestion

Derek Cohen, in Perth Australia

>Bruce

I made a marking knife out of an old circular saw blade a few years ago. Not knowing any better then, I just cut it out with an angle grinder, filed to shape and sharpened it up. I still use it today. It doesn't seem to require much sharpening and has a lethal edge.

I have also made scraping blades (for my #80) from old circular saw blades. These work well and hold an edge as long as (or longer than) the original blades. Being slightly thicker they are nicer to use.

Regards from Perth

Derek