[R-390] D-Hole Punch

[Flowertime01 at wmconnect.com]

Barry,

Along with filing holes and making lots of metal bits to clean out is to
use a router. Pick up a small (< 1/4 ) bit and use it to do the D hole.
The smaller the bit the closer you get to a true D shape.

Some duct tape and felt pen will help you get a template to route to.
Some lumber cut for filler will get you a level surface on the back or a 
chassis
if you need it. 

After you drill a hole large enough for a D punch you already have a lot of 
metal in the chassis and the extra from the router is not that much more. The 
router bit will turn a larger chip than a file will. A high speed steel bit 
will last long enough to work a hole into the chassis. Change the router plunge 
depth and start the second hole with a fresh bit of bit.

If you do not have a router you can use a router bit in a high speed drill. 
The higher the speed the better. I cannot foresee you using a drill press and 
sliding the chassis around on the drill table. But then one works with the 
tools you have.

Roger KC6TRU