Please recomend a steel for my aplication?

[cacrawfo]

Hello,
I would like to make some small tooling adaptors to mount a strange type of cutter to an easily available sheel mill arbor for R8. The adaptor will mount to the sheel mill arbor, the cutter will mount to the adaptor. I would like to make it from something that machines nicely, holds detail, can be heat treated to some degree, and can be black oxide coated. I am thinking maybe one of the tool steels?

Beyond that, I am not sure where to start on a material.

Thank you for any suggestions!
Carl C

[RICHARD ZASTROW]

There are many choices available. One I use often is 8620. Readily available, fairly easy to machine, case hardens well and keeps a tough core. Relatively inexpensive compared to most tool steels.

[davereagan]

Hello,
Any time you heat treat something, it can move and for this application, you need it true and flat. That leaves you with grinding afterwards, which is expensive, or not heat treating at all. One material that covers a lot of applications like this is 4140HT. It's already heat treated to 28-32 Rockwell, but is still machineable. Truth be told, your application would probably be fine made out of 1018 HRS. But with 4140 HT, you can machine it and leave it. It's strength is way beyond mild steel at 130,000 psi yield and 150,000 ultimate tensile strength, but it isn't that bad to machine. One thing a lot of people think including engineers, which is untrue is that hardened steel is more rigid than mild steel. The modulus of elasticity (spring rate basically) does not vary much at all for the whole spectrum of steels. Unless you were to load this adapter in some extreme way, you will probably never even reach the 40,000 psi yield strength of mild steel. If this is true, it will perform as well as a hardened piece for a lot less money. 4140HT is available off the shelf at Mcmaster.com and other places. Good luck.

Dave

[cacrawfo]

Ok,
Thanks again for the help! I had looked at the 4140HT, and I believe that also gives a very nice surface finish compaired to the 10XX series steels? A local shop that I buy small pieces of material from has a lot of the 4140HT.

I'll give it a whirl! Prove it in 6061AL, then some steel.

Thanks!
CArl C

[davereagan]

Carl,
I've considered making my own Cat40 Tooling, but I haven't seen Cat40 "blanks" at an affordable price. Maybe I could buy a short holder for $50 and anneal it. My idea was to make an integral face mill that could take an inch off the gage length of even the shortest possible bolt together combination. I have a machine with more horsepower than rigidity, so the shorter my gage length is, the closer I am to the bearing and the harder I can cut without ugly sounds and finishes. What kind of adapters are you planning to make?

Dave

[larry53]

Originally Posted by cacrawfo Hello, I would like to make some small tooling adaptors to mount a strange type of cutter to an easily available sheel mill arbor for R8. The adaptor will mount to the sheel mill arbor, the cutter will mount to the adaptor. I would like to make it from something that machines nicely, holds detail, can be heat treated to some degree, and can be black oxide coated. I am thinking maybe one of the tool steels? Beyond that, I am not sure where to start on a material. Thank you for any suggestions! Carl C

There are many types of tool steels you can use. I use a lot of A2 which is
air harden tool steel, can be machine but is not as soft as a carbon steel.