On 2011-04-16, Steve B wrote:

"Ignoramus1116" wrote in message
...
I am trying to understand a little better, how to drill stuff with
CNC.

My current approach amounts to "winging it" and deciding something
like "it oughta be good enough at 2 IPM".

Well, I think that I can do better than that.

I looked and have not found a decent drilling calculator.

My feeling is that the drilling feed rate in any given material is
calculated as inches per revolution, and IPR is proportional to drill
diameter.

Does anyone know of some good tables for this sort of thing?


i

I go by looks. As long as I'm getting nice looking chips or spirals without
a lot of coloration indicating high temperature, I'll settle for a speed
that cuts and doesn't have me changing bits frequently.




I sort of do the same thing, too. With a manual mill, the operator is
pushing on the quill by hand and the feedrate is easy to change. With
a CNC, the rate is in the program. It may be easier to break the drill
in case of a mistake.

i