-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Can HSS be turned?
- Thread starter strantor
- Start date
B
bvd1940
Forum Guest
Register Today
Just use a ceramic insert and have at it. I use old milling cutters for small centers by turning to a point.
)
)
I don't know about endmills but I've turned a lot of drill bit shanks down for friends and carbide cut them just fine.
but at the tip, where (I assume) it's heat treated? I'm thinking to turn either a drill bit or an end mill into a cap head counterbore bit.
Never heard of ceramic inserts. I'll look into it. Thanks.
I'd be careful about any sort of annealing as it might knock the hardening out of it. The shank part of drill bits and end mills are not as hardened as the cutting part. That allows their respective holders to grab on a little better. Hardened tool steels could be as high as Rockwell 60-65 range which won't be easy to work with. I've never tried and don't know off hand how well that can be turned. About the highest I've never knowingly worked on was about RC 48 and it cut OK with carbide.
Ray
Ray
T
Tom Griffin
Forum Guest
Register Today
No you can't turn the business end of a drill bit. Anything hard enough to cut it will be destroyed by the interrupted cut. If you want to modify the diameter or the cutting edges, you'll need to grind them. If you need a special cutter, you might try making one out of O1 drill rod and then heat treating it. As far as annealing a high speed steel drill, you can, but then you wouldn't be able to harden it again because heat treating high speed steel is pretty much out of reach of most hobby metallurgists.
What is it you are trying to do?
Tom
What is it you are trying to do?
Tom
I'm getting the feeling that you're sparing me a couple of semesters worth of in-depth technical explanation with this line. So it would be more complicated than heating it to non-ferrous, and then dunking it in ATF? I have an acetylene torch
Well the question is mainly just a theory question, but I actually do want to make some counterbore bits for cap head screws.
Yes, it's a bit more than heating with a torch. You have to know the material, normalize it, and within 1 hour of normalizing, heat it to just beyond it's critical temperature (usually around 1200-1500 F) hold it for the soak time (depends on thickness but it's usually 20 mins per 1/2"), quench it then, re-heat to desired annealing temperature and then either quench or air dry (depending on material). If you don't hit the critical region or, exceed it by as little as 150 degrees, -you need to re-normalize it and start all over.
The main issue here is you don't know the precise material type. For heat treating, you must know the material type and follow a cook-book that tells you times, temperatures and annealing levels. Each metal varies a little and it makes a difference.
You can buy a set of counterbore bits for 30-40 bucks...
The main issue here is you don't know the precise material type. For heat treating, you must know the material type and follow a cook-book that tells you times, temperatures and annealing levels. Each metal varies a little and it makes a difference.
You can buy a set of counterbore bits for 30-40 bucks...
I'm getting the feeling that you're sparing me a couple of semesters worth of in-depth technical explanation with this line. So it would be more complicated than heating it to non-ferrous, and then dunking it in ATF? I have an acetylene torch
Well the question is mainly just a theory question, but I actually do want to make some counterbore bits for cap head screws.
I've been watching youtube videos just now, about tool post grinders. I think I might be able to build one. Still hoping that won't kill my hardness.
I hear what you're saying about buying the proper cutters (they aren't that expensive) but what fun would that be?? And what would I do with my dull bits? Ah well, I'll probably end up buying them anyway, when all my "clever" plans fail.
I hear what you're saying about buying the proper cutters (they aren't that expensive) but what fun would that be?? And what would I do with my dull bits? Ah well, I'll probably end up buying them anyway, when all my "clever" plans fail.
You'll have to grind them. I've taken countless twist drills and ground the first 3/8" or so (depending on the diameter) down to act as a pilot that fits the drilled hole I wanted to counterbore. It's a little tricky to get it to size and be concentric all freehand, but it can be done. Of course, the cutting edges of the counterbore should be square to the tool axis and relieved in order to cut properly. It just takes a bit of practice. Certainly not worth annealing and re-quench and tempering. I'd buy them before doing that, but easily I'd grind what I needed. But sometimes, a regular square ended end mill will work as a counterboring tool.