MOTM

--- In motm@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:
> 
>   I typically use a sheetmetal punch for rectangular apertures.  The 
> thickness of an MOTM panel is at the very limit of what I consider 
"safe" 
> for the punch, however.  What I need is one of those nifty CNC laser 
> cutting tables...
> 
> Crow
> /**/


Ah... that would be nice....

For rectanglular holes I have been using drill bits close to the width 
I'm looking for and then making a row of slightly overlapping holes 
along the same centerline. From there I work the "points" down with a 
file and also cut my corners with the file. The results are very good 
if you take your time when approaching the size you are looking for. 
Having the right measuring tools is a big plus. +/- .005" can be had 
this way with a little patience. I try to get within +/-.0001". I'm a 
metrologist for a living so I kind of feel compelled to sit with a 
bunch of files for hours on end. 

+/-.010" will look fine. An average human hair is about .0025".

multiply by 25.4 for m