Harold:
In your earlier comments on carbide bits you mentioned "Stellite" bits as
being preferable to carbides and HSS. I looked through my bit bins and
found 6, full length, 1/2" Stellite bits with a tool only on one end. I
also noticed that many of my bits were Cobolt, with various designations.
In the past, I never really paid attention to the bits, other than to select
carbides for really hard stuff and cast iron. Now that I find that I have
a goodly variety of all types, some guidance on their usage and
advantages/disadvantages of each would be appreciated.

1. Am I correct in assuming that one grinds stellite bits on a regular stone
and not on a green stone? Seems to work okay and grinds at about the same
rate as HSS bits.

2. Cobolt vs ordinary HSS. What does Cobolt provide other than bigger
cuts, higher temperatures, faster feeds, slower wear, etc. Other than cost,
are there any reason why one would not prefer Cobolt over HSS?

3. Stellite vs. HSS /Cobolt. Advantages, disadvantages, preferred metals
to use on, contra-indications, special problems and issues.

4. Stellite vs. carbides. You said earlier that Stellite would take to
interrupted cuts better than carbides. How about ease of getting a good
finish, lower pressures, etc. Any other advantages or disadvantages of
each.

5. Any special issue, for a given metal to be cut with respect to rake,
relief, etc? for each:: HSS, Cobolt, Stellite, carbide.

Any other sage bits on bits that you might want to put into the book
I've asked you to write?

Boris


-------------------------------------
Boris Beizer Ph.D. Seminars and Consulting
1232 Glenbrook Road on Software Testing and
Huntingdon Valley, PA 19006 Quality Assurance

TEL: 215-572-5580
FAX: 215-886-0144
Email bsquare "at" sprintmail.com

------------------------------------------