On 15 Oct 2003 22:27:57 -0700, (Lennie the
Lurker) wrote:

"Robin S." wrote in message ...

What's normal turning? I would think facing and turning as opposed to
grooving and forming. In this case, why does HSS *win*? With what little
experience I've had in toolmaking, radius tools are constantly used along
with other form tools. In this case, carbide is a loser. However, I don't
see why anyone would use anything _but_ carbide for turning/facing.
Esspecially with high carbon, high alloy tool steels and machine steels
(like 41freakin'40).

Normal turning is anything you would do on a lathe, including
grooving, forming and threading. Carbides can be very "hungry", but
unless you've got lots of power and rigidity, it comes second to a
good high speed tool. A solid 14 or 16 inch lathe would be about the
minimum I'd even look at a carbide for, the smaller ones just don't
have what it takes. Most of us have smaller machines or imports, and
carbide is the way to ruin both your budget and your machine. Very
few of the bench machines are heavy enough to run carbide without
either shortening it's life, or making your life miserable. But,
(Giggle, snort), I don't use carbide, and I'd rather work 4140 or
4140HT than the gummy soft stuff. May take me a while longer, but
normally I get a good finish, hold size easily, and if I want to
polish it, nothing else comes up as nice.

HSS can be run as efficiently as carbide if kept sharp?

Ummmm, yes. If a job has something, like an interrupted cut, it can
raise hell with inserts, and I've seen it pull the brazed tools apart.
However, the only time I ever stopped the spindle on the 7A J&L was
with a 1/2 inch radius on a 1 inch square piece of Congo. However,
one of the common things that I've seen is people wasting time trying
to make a carbide work, because "High speed would take too long."
Usually, by the time they give up and use the HSS, they've already
wasted more time than it would have taken them to use the HSS the
first time. Carbide can remove a lot of metal in a hurry, but power
and rigidity have to be there or you're wasting time.


Damn..something else Lennie and I can agree on. There is a (insert
Diety of your choice) afterall!

Gunner

"You cannot invade the mainland United States. There would be a rifle
behind each blade of grass." --Japanese Admiral Isoroku Yamamoto