Re: [CAD_CAM_EDM_DRO] Re: What do you think of this mill?

High Tech wrote:

> Doug
> I don't understand the specs either. Mine says 1-1/4" drill and 1/4" tap.
> The chuck only holds up to a 1/2" so I don't know how you get 1-1/4" unless
> it is a stepped drill.

Generally, drills over 1/2 inch have a Morse taper or similar mount. A Jacobs-
type chuck is just not strong enough for the larger drills. You can run them
with R-8 to Morse adaptors, if your mill has an R-8 spindle taper.

(The stepped-down, or Silver&Deming drills, are crude hacks for small machines
and electric drills. They work, but don't work well. The stepped-down end puts
excessive stress on the Jacobs chuck, and the drills can wander.

> As for the 1/4" tap this maybe a safety issue as the
> lowest speed is 95rpm on mine. I have not had this unit very long. But I can
> say it drills steel very easily I have gone up to 5/8" low speed 450.

A 1/4" tap. power driven into tough material can draw a LOT of power.
I remember watching an automatic screw machine making something where
a tap of about 1/4" was driven into a new workpiece every 15 seconds or so.
A HUGE mushroom cloud of oil smoke erupted out of the machine every time the
tap went in. I suspect the machine could run a larger tap into aluminum easily.

Jon