I don't know about the hydraulic part, but
I've had really like my Greenlee
punches.
That is the sort of thing I've read elsewhere. Greenlee are not cheap, but they
do the job and last. The brand we used to use in the UK was Q-max [1] but
they don't do the sizes I need
[1] Again a good brand IMHO. I convinced my father to buy me the 5/8", 3/4"
and 1+1/8" ones about 35 years ago. I am still using them. Of course those are
the sizes for B7G, B9A and Octal valveholders... I think the company started out
making RF (and IF?) coils, hence the name.
The ones I am looking at are the conventional 'tighten the bolt' ones albeit with
a thrust type ball race on the bolt to reduce the torque needed. The published
specs exceed what I need to do (they are specified to punch 1.6mm mild steel,
the thickest I want to do is 1.2mm).
The hydraulic thingy seems to fit in place of the nut and pulls the punch bolt
through the metal into the die. Nowhere can I find info on what advantage it
gives. If it's just quicker then I am not going to get one.
-tony