Re: ATM Teflon etching question

[andydtg@alpha1.phoenix.net]

Stephen Tonkin wrote:

>Ignorance of terminology:  What is a "Forstner type bit".  From the
>context, I assume it is a flat wood-drill that fits in an electric drill
>chuck -- is that correct?

Actually it's not a flat bit but a cylinder shaped one with flat radial
cutting edges and 2 almost 180 deg circumferential cutting edges. These
sometimes have saw teeth on them. Visualize a hole saw with 2 radial 
cutters that also plane off the interior of the hole & you've got it.
Usually used in a drill press & can be used to bore partial holes in
the edge of the stock if properly clamped in place. Cut extremely smooth
edged holes without splintering. Also very expensive, especially in
the larger sizes (up to 3" usually). China-made sets 1/2 to 2" or so
can be had for abour $30-40 US. They do have a center point so the hole
is not completely flat bottomed but it's much smaller than that
on a spade bit.



Andy Saulietis / DTG Alt-Az-Fp Drive Systems
12617 Harriet Ln
Santa Fe, TX 77510 USA
409-925-8854 Voice/Fax