HSS is also inexpensive for what you get and it will also last a lifetime if properly ground and maintained for my own use. If I need something special I just grind it and get right back to work.
HSS is also inexpensive for what you get and it will also last a lifetime if properly ground and maintained for my own use. If I need something special I just grind it and get right back to work.
Bottom line is if it is working no matter what it might actually be the why change it?
HS tools give a better finish than carbide does and that might be a good reason to switch, particularly for those who turn slow. From my experience, the only carbide that I can get a good finish with my setup are the "Finishing" inserts that are very delicate to handle and chip if one looks at them wrong. Now, I'm an old man and not trained to be a machinist sooooooooo. Doesn't cost a whole lot to put an new edge on a HS tool.
Pete
this morning of a gunsmith truing a Remington 700 bolt. He was using a HSS cutter he had ground himself. Left a very nice finish considering he was making very lite cuts. I think it's important to hone cutters well after one grinds them if one wants a nice finish.
Pete
So back to "hardening...."
You'se have my attention. Can I heat/quench/anneal ("draw back") a typical HSS toolbit?
I'm quite adept at making scrapers and springs and knives and such from carbon steel but I've never tried "harden" a 1/2X1/2 tool blank so I'm asking.
"Can I shape a tool, get it set up to cut then heat/quench/draw it, hone the edge back to razor sharp???"
Do some of you do this with HSS tooling?
Nope, never. The blank is provided hard, and you can only muck it up from there.
OK, it *is* steel, so you can screw up the hardness, but you'll never get back to as good as it was unless you have the same facilities as the foundry that produced it.
Buy the hardness / temper you're after, and preserve it during grinding (not as hard as it sounds, HSS is resilient stuff).
You *can* buy some O-1, or W-1 (annealed) and machine or grind to shape, harden and temper. It's much easier to make a cutter that would otherwise take a long time to grind, but the result won't be as good as one ground out of HSS (I'll allow that there might be special applications where this approach is somehow superior, but they are outside any domain in which I've worked).
GsT
Nope, never. The blank is provided hard, and you can only muck it up from there.
OK, it *is* steel, so you can screw up the hardness, but you'll never get back to as good as it was unless you have the same facilities as the foundry that produced it.
Buy the hardness / temper you're after, and preserve it during grinding (not as hard as it sounds, HSS is resilient stuff).
You *can* buy some O-1, or W-1 (annealed) and machine or grind to shape, harden and temper. It's much easier to make a cutter that would otherwise take a long time to grind, but the result won't be as good as one ground out of HSS (I'll allow that there might be special applications where this approach is somehow superior, but they are outside any domain in which I've worked).
GsT
Say what?
Of course the hardness can be manipulated.
Sometimes it is easier to soften it up to make complicated tools, and then then harden it back up.
It hardens just like every other decent grade of steel.
Heat to red hot.
Allow to cool slowly.
Shape.
Heat it back up to red hot.
Quench in oil.
I often quench in used motor oil.
Temper to improve toughness of core while maintaining surface hardness.
Once you have a multi meter with thermocouple inputs it is not all that hard
to nail temperatures.
The actual temperature points are not all that hard to find and achieve.
tx Gene.... I misunderstood
I'm very happy with using HSS in many applications and can get a beautiful finish but the one place I'm having trouble is when timing multiple surfaces to each other.
I just often do stuff in ways that noone else does so my problems are often peculiar
Here's where I join the "show me" state. I have heat treating ovens (well, down to one) and thermocouples (like the one in my oven) are no mystery. You muck with a piece of high-quality HSS and you're not getting back to the homogeneous hardness of the manufacturer. You can't quench the center of a piece of metal - you'll always be quenching the outside and much later that 'coolness' reaches the center. As I said, you can play with O-1 and W-1, exactly as you've described, but do it with HSS and you're just ruining a good tool blank. A good piece of HSS was created with multiple processes generally outside those practical for the home-jobber. You need *hours* of soak at specific temperatures, in oxygen-free environments, to achieve the same hardness / temper through and through. The idea of a hard exterior over a ductile core has merit - that's what you can do with high-carbon steels, but it'll never match the quality of HSS for lathe work.
GsT
Having started out as a toolmakers apprentice almost 60 years ago and still working as a Toolmaker/Gunsmith, I have never seen it done or had to do it myself. Just grind to shape and hone the edge. If that is to difficult just buy the A. R. Warner HSS inserts.