re:Cutting speeds

Ian,

You STILL have the use of your ears, nose, eyes!...
And a feedrate override in most cases...
And on higher end machines, a "load" meter or two...

So...
Extrapolate from your experience when possible.
When not possible, extrapolate from others' experience...

1) With books (like machinery's handbook, tooling catalogs, etc.).
2) Pick up the phone and call a tooling supplier/mfr(mfr preferred,
IMO) Also check with the material supplier, in some cases
3) Ask, on a mailing list of machinists... :-)
4) "guesstimate" based on the cutters' original use (dental burr used
for tooth enamel (hard,brittle material) is used at very high speed.
4a) Also base your start point on tool geometry, using what you
already know or can find out.
5) Keep one hand on the "off/stop" button(s)
6) Buy AT LEAST TWO tools!!

Hope this helps.

Ballendo

>How do you decide on an appropriate feedrate for materials and
>cutters you haven't used before?

<big snip>simply by using my ears and the feel of the handwheels but
this isn't possible with a cnc machine as you have to program
in a feedrate and then just hope its Ok.