Drill bushings are not expensive, when you consider the use you will get out
of them. Make a drill-jig out of angle or channel for each model and put
bushings in them. color-code hole sizes, clamp the jig on the workpiece, and
drill one size, change bits and do next size, etc. Or as Wm and Roy
mentioned, get multiple drill-presses to speed up the work. At $200 a pop
from Harbor Freight, it ought to give you the production gain you wish.

As for the breakout burrs, consider making a channel in the table, and put
up a fence to keep the piece aligned with the channel. Deburr as a final
operation, not one-at-a-time.

Flash
"Dave99" wrote in message
...
I've been trying various things over the last few years and I'm just
curious if there's any engineering geniuses out there that have a
better way to do this...

I drill thousands of holes in 1" and 3/4" aluminum square tube (1/16"
thickness). The holes are mostly around 1/4". The distances between
the holes are varied... Could be anything from one inch to a foot.
Also, the 1/4" holes have to go through both sides, but there is also
a smaller third hole on one of the remaining sides that match each of
the first two holes. Because I do so many of these, I'm just looking
for the smartest and quickest method possible. Multi head drills are
out because many of the holes are too close. CNC would be great, but
that's not an option right now. What I have to work with is basically
one drill press. So far I've just tried using one master piece and
then altering the distance of an end stop. That's not great because
then you have to move each piece in and out, which can get tiring
since some pieces are 5' long. Then I went with a template, but the
templates wear out fast and it also doesn't work well with the full
size bits. A smaller pilot bit has to be used first for accuracy, so
then that makes it even longer to drill everything twice. Another
thing that slows things down is that even the smallest amount of burst
burs on the bottom have to be removed in-between each drill move, or
the burs will make the bottom uneven and destabilize the piece on the
next hole.

So far I'm thinking that maybe I could have a jig where there's pre-
marked holes along the length of a base tube, where you could move a
peg tab from hole to hole, using that as your backstop. Then the burr
problem could be eliminated by having the tube sit on top of the open
end of a channel, so there would be space in the middle. I don't know,
that's the best idea I've come up with, but it would still mean moving
each piece in and out for one set of holes. Also, the more you shift
things, the more you run the risk of screwing up. After drilling about
80 holes in one piece and then screwing one up because you flipped
when you should have flopped... that's when you start looking for a
gun. My dream is to have something where you just lock it in and watch
it go, but I don't think I can get something like that right now.

Dave