"John P." wrote:

On Sat, 31 Dec 2005 15:47:27 GMT, "Pete C."
wrote:

I disagree, the commercially available 20T H presses are quite
inexpensive and will save a lot of time and effort tracking down the
steel, welding and trying to keep things square. My recommendation would
be to use a commercial 20T press frame as a starting point. The 20T jack
can readily be used separately as a normal jack.

You should be able to find a suitable hydraulic cylinder, valves and
pump unit from a place like http://www.surpluscenter.com and have a fast
powered unit operating in short order.

Thanks for jumping in Pete. Let me see if I understand correctly:

If I were to purchase, from Harbor Freight, the 20T Air / Hydraulic
Bottle Jack (Item 41487) along with the 20T Shop Press (Item 32879), I
could replace the stock manual bottle jack with the Air / Hydraulic
bottle jack to more or less duplicate your machine?

And all I would need to do is hook it to a sufficient air source for
power? Would a 13.3 CFM @90 PSI compressor do the job?

Also, being a complete newbie at anything air or hydraulic related I
am not following along very well with how you created the foot pedal
or the use of the Bimba. Could you attempt to explain exactly what is
going on with the control unit?

Assuming the press will work for Damascus, even if it isn't ideal, I
will purchase the components and fabricate it. I'll even document the
process for everyone's benefit. But I'll definitely need a little
more information / guidance on the foot pedal stuff.

Thanks,

John P.

It was a different Pete that posted about the foot pedal and air
cylinder operated release valve. I believe he posted a link to some
pics. As for the basic press, the 20T air/hyd jack will just swap in
place of the 20T manual/hyd jack that comes with the press.

90 PSI probably won't make the full 20T, but it should produce close to
it. I think you need close to the 120psi max in order to reach the
relief valve limit. Easy enough to test, just stack a couple solid press
plates and press on them. If the air pump stops cycling then you haven't
reached full pressure, increase air pressure until the pump keeps
cycling and you've reached the hydraulic relief valve setting.

If you need a faster full hydraulic powered press you can still take the
basic 20T H press as a starting point. Remove (or don't install) the 20T
jack. The top frame will be two "C" channels with a gap between and a
heavy plate welded on the bottom.

Find a front mount ~10" stroke hydraulic cylinder that will fit the gap
between the "C" channels. Drill the appropriate holes in the heavy plate
to mount the hydraulic cylinder from the top with the ram pointing down.
Where the ram touches the upper press plate where the original jack
would sit, weld a piece of steel pipe to act as a receiver for the ram
so it can't slip to the side.

After the cylinder is mounted it's simply a matter of connecting a
hydraulic power pack and valve to complete the press. The GPM flow rate
of the hydraulic power unit will determine the press speed. A power unit
with a two-stage pump will provide a faster closing speed followed by a
slower pressing speed. Valving can be anything from a basic lever
actuated valve, to a rocker foot pedal, to a solenoid valve and hand
button pendant.

The ultimate pressing force will be determined by the hydraulic cylinder
bore and the max PSI of the power unit. 2,200 PSI or so would be typical
for a setup like this. If the cylinder that will fit between the
channels does not have a large enough bore, you could use a larger one
with a longer stroke that can mount above the channels and use longer
grade 8 bolts to fasten it to the bottom plate.

Either way, starting with the commercial 20T press for the $200-$300
will save you a lot of work.

Pete C.