On 2011-11-07, Jordan wrote:
I'm wondering what the capabilities are of a couple of flypresses I have
- recent aquisitions.
One of them is quite big, I guess it weighs 300 lbs at least, the other
one maybe 100 lbs.

These are the ones with a screw feed and a long arm with weights
on each end to turn the screw? Or the ones like I have, with a flywheel
dog-clutched to a heavy shaft with an eccentric making one stroke of the
punch for each trip of the dog clutch? An electric motor keeps the
flywheel spinning.

It'd be great if I could use one of them to punch several 3/16 inch
holes in mild steel plate of about 1/8 inch thickness or a bit more.
Is this the sort of job for a flypress? I'm thinking of a quicker
alternative to drilling.

It is the sort of job at least for a flywheel press. You need
to look in _Machinery's Handbook_ for the formulas, but the required
tonnage (my smallest one is a 1 ton, and I have a 2-1/2 ton one. The
rating is on the flywheel in the smaller one), is a function of the
perimeter length of the hole, and the thickness of the metal (as well as
a constant based on what the workpiece material is).

Just working from memory, but I think that a single 5/16" hole
in 16 gauge (0.0625" thick) brass (not even mild steel) was the limit
for the 1 ton unit. (or was it a 1/4" hole?) With 1/8" thick steel, I
suspect that one ton might get you to 1/8" holes, but not much bigger.

So -- you need the tonnage rating of the press. (And if it is
the kind with the weights on arms, I suspect that the work required to
spin the arms will be not much quicker than using a drill press with a
proper spindle speed.

Good Luck,
DoN.

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