You don't say what size or HP your drill press is. As you probably already
know, the correct time to make the holes would be before the finish coating
is applied.

How will you be locating the location of the center of the hole? Center
punch? That's about how long a punch would take to make the hole.
Any drilling or hole saw method will take considerably longer than punching.
Some odd/uncommon/custom carbide-tipped spade bit with a center pilot drill
may be faster if you could find, or make such a cutter.

You will most likely spend a considerable amount of time deburring the
holes, regardless of the method you use to make the holes.
Step drills will deburr the entry side of the hole if you just kiss the next
step on the hole.
If the hole is located in the back of a box (not the sides), the deburring
time could be quite a bit faster, by flipping the part over to deburr.

I would hate to attempt to make that number of the holes without any cutting
lubricant, maybe not liquid, but at least beeswax or even bar soap (not
highly effective, but not extremely messy).

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"K Ludger" wrote in message
...
I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick,
probably 30 - 35 thou. Punching is out, I need to do this using my drill
press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to
avoid using coolant or Trefolex due to the cleanup involved with the
enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill)
any recommendations as to the best approach or tool that I should use?

thanks