And keeping a square punch and die aligned? I've only seen
round punches for the Whitney. (Though I would be glad to learn of the
ability to do square and other shapes.)
In the meanwhile -- what *I* would use would be a 1/4" square
broach -- which I already have. However, note that the pilot hole is a
little over 1/4" for that, so the sides of the hole will have a slight
scallop on each side. I would use an arbor press to drive the broach,
and would use a drill press to make the pilot holes, unless the location
was quite critical.
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How many and how accurate? For just a few, drill a hole and use a
triangular file. 10 ga is .134" IIRC, that will take a serious punch and
die set to do a series of them, about 3-1/2 tons of die pressure.
Well, I'm glad you aren't trying to cut *large* 1/4 inch square holes,
they're pretty difficult to do right.
But the small ones are easy, just get retro and pick up a 1/4" square
WATTS BROS TOOL WORKS, INC.
760 AIRBRAKE AVE.
PO BOX 335
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The company is so retro themselves that I don't believe they are
bothered about not having a web presence yet, or if they have one it's
pretty well hidden.
For any folks who think I'm "smoking the drapes" about the square drill
thing, there's a photo description of a polygon drill at:
IIRC these were the drills that made the carriage bolt what it is today.
A pyramidal broach? Ie, take a 1/4" sq. broach, taper it a little (might
need a grinding house to do this right), drill a 1/4 or 15/64 hole, and
broach away, proly doable on a BP or a drill press.
Greenfield makes a "knockout punch set" for electricians, where you drill a
3/8 or 1/2" starter hole, and thread the male/female halves of a threaded
ball-bearing punch set on either side, and ratchet out your desired pipe
opening--over 2" in many cases.
Maybe you can locate this style of punch for small square holes, altho you
are dealing w/ a substantial thickness for that dimension.
Very fine O/A might could do it also. You can get amazingly smooth cuts w/
O/A, esp. if you get the heat right, and it kind self-rounds the edges--if
you desire. Or it can leave them quite sharp. You'll need some kind of
fixturing guide, for height and dimension. Will take some practice, also.
The 12 ga shotgun suggestion may just be a good bet!
formerly Droll Troll
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