Re: Making Flat secondaries - disaster #1...

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Goinbonkers-at-aol-dot-com>

I am not understanding the difficulty here.  I have drilled a lot of holes in
Plexiglas and have had no trouble at all.   A good sharp bit and clamping it
securely to a piece of plywood on my drill press is all I ever did. 
Mike 



>
> I have to disagree with this, Trying to drill a 1\2" hole that is pre 
> drilled will definitely grab into the part! 
>  A real good bet when drilling acrylic and lexan is to grind your bit 
> into a very wide included angle, the included angle should be around 160 
> deg. so that it chips away at the material, not cutting into it. 
> Also, I have found that straight mineral oil used as a lube on jig saw 
> blades, or drill press bits and hand tools will allow a good clean cut 
> with little cleanup. 
> drilling acrylic is much like drilling cast iron, (except for the 
> melting at high cutting speeds) If slightly less then flat cutting 
> angles are used it will peel the material out of the hole very nicely 
> with mineral oil as a lube. 
> Hope this helps, 
> Marc M. 
>