To Frif You asked if a 20 ton jack can be used reliably without a
guage . Really the only operations that don’t need one are bending or
forming where you can see very well how much your work is being worked
and you can absolutely stop pressing when you need to. The other kind
of work that doesn’t need a guage is blanking with pancake dies. It’s
virtually impossible to achieve consistent repeatable results on
forming you can’t see unless you have a guage. The hand pumped jacks
are better for this unless you install an adjustable automatic cutoff
to a motorized pump.
If your jack doesn’t have a gauge on it already, you shouldn’t put
one on without consulting someone (not me) knowledgeable beforehand.
My experiments with building presses and modifying jacks have been
messy, frustrating, time wasting and would have been funny if they
weren’t dangerous. If you MUST build your own press, use a tried and
true design. 20 tons can destroy more seemingly indestructible steel
and welding than you think.
If you only plan on cutting parts with RT/pancake dies then a guage
isn’t needed. When the die pops, the part is cut and you open the
press and start over. 20 tons is way more than enough for any blanking
die you’ll ever use on jewelry, by the way. Around 15 tons is the most
I’ve needed for large (4" by 6" ) complicated designs cutting
…20ga. silver or copper.
You can learn more at the Hydraulic Die Forming Forum. Don’t have
the url, but you can visit www.bonnydoonengineering.com and link to
the forum from that homepage. Watch out for a psycho named Dar.