--Having a little problem with same. I'm trying to bore 2-3/4" dia
holes thru 2-1/2" thick 304 stainless; gotta do 4 parts. I managed to get
the pilot holes up to about .875" with available drillbits, then I switched
to a boring head and, moving in increments of 0.1" on diameter I got the
holes enlarged to about 1.2" but then suddenly it got reeeeal hard to cut,
even with a carbide tipped boring bar. Shallower cuts seem my only option
but at this rate it'll be winter B4 I get the holes finished! I'm going to
go see a pal with a honkin' big lathe who can speed things up a little bit
and that will solve the predicament.
--But I'm thinking *next* time I'll want to do something different
like use an endmill and a rotary table to hog out that kind of material,
then do a cleanup pass on my wimpy little lathe. I'm curious to know what
others have done in similar situations. Any ideas?

--
"Steamboat Ed" Haas : A human without a critter
Hacking the Trailing Edge! : is incomplete..
www.nmpproducts.com
---Decks a-wash in a sea of words---