Re: [CAD_CAM_EDM_DRO] Cutter geometry (Was backlash)

Hi Chris:
Can you tell us a little more about the problems that you are having
with your current setup?
I'm a little unclear about what you're trying to cut, and I can't quite
visualize your setup.
Are you trying to cut a tapered part in one pass?

>(I'm trying to cut .014 to .125 deep in a single pass, on a 9"
>south bend <

Is your problem related to finish, or dimensions, or both?
What speed are you running the machine at?
Is your tool positive, negative or neutral rake?
Is it honed?
What diameter is the stock?
How well is it supported by the travelling steady?
What do you need to achieve?
Why did you choose drill rod? ( tends to be poor for turned finishes unless
hardened.)
How many do you have to make?

Jeez, I sure ask a lot of questions!

Cheers

Marcus

PS: To answer your question as best I can with what I know so far, HSS is
often a good choice for applications where finishes are hard to achieve
because of spindle speed limitations.
I wouldn't bother with 1/2" square HSS though; it's way too hard to grind,
and on a small lathe the limiting factor will be the rigidity of the spindle
and carriage.
A 1/4" square tool will be ample.
Get a 5% cobalt tool, grind a bit more top rake than you normally would and
grind the point dead sharp.
Then get a medium to fine India stone and dress a 0.005 rad on the tip.
Hone the tool really well.
Run with heavy oil as a lubricant for the tool and the steady at as high a
speed as you think the tool can stand.

Cheers

MC