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

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.

Recently had several hundred 4" diameter X 1/8" thick *galvanized* disks laser
cut. Was *way* cheaper than I could have cut them with a hole saw even if I
paid myself minimum wage.

That particular shop only had punches to 3 1/2" so I did not get to compare
prices of the different techniques.

There are also online retailers that sell plain steel disks in various sizes
and thickness. Costs were higher but lacked the minimums and lead time of the
local shop. No galvanized and the shipping was outrageous on the few I bought
to hold me until the local order was done.

http://www.wagnercompanies.com/disks_and_plates.aspx

Is the vendor I used, curiously they do not show a 2 1/2" in 3/16".
2 3/8" and 2 7/8" are both offered in 3/16" thick so perhaps it is just missing
from the list?
--
William