On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
My son could probably stamp out a few thousand per shift once the die
is set up.
Gerry :-)}
London, Canada