On Tue, 26 Feb 2008 03:31:55 -0800 (PST), wrote:

I need to get some parts made, and am going to approach a few of the
local and online cnc machine shops. I need 300 tubes made, and up to
now I have been doing these on my manual lathe in lower, "as I need
them" quantities.

On my lathe, I was able to hold a .0005 tolerance, which I think would
be called +/- .00025.

Is asking for +/- .00015 too much to ask for a cnc job? Would this be
deemed extreme, or add to normal costs?

Please, only helpful and productive replys.

thanks!

Why do you need 4 digits tolerance? Particularly if you have been
doing them on a manual lathe?

Depending on the part, material, setup AND machine, you could
reasonably expect .0002 0/+ repeatability with CNC


The most dangerous thing in the world, is a CAD package with more than
4 places to the right of the decimal point.


The big question is...how "accurate" can you afford?
Gunner