On Thu, 06 Jan 2005 07:12:05 -0800, Grant Erwin
wrote:
Lloyd E. Sponenburgh wrote:

Hi,
I'm a farm owner. I recently built a 20-ton hydraulic press for pushing
bushings and bearings, and for straightening bent shafting. It works
fine -- two-hand operation, a motor spool control so I can "nudge" work, and
a two-stage pump to give good ram speed with a high end pressure.

But the NOISE! It darned near drives me out of the shop!

It could be your hydraulic pump is cavitating. Google. If your machine
was made by a US company you might call them up and ask them if a rebuild
kit is available.

I was afraid that had happened to me on my ironworker. But then I tore
it apart and cleaned the tank meticulously and refilled it with new fluid
and now it's much quieter.

Educated Guess: Check that the hydraulic system output relief valve
is opening, and that it's set right. (Do you have a pressure gauge
on the pump output, or on the press cylinder ram?)

If the pump is churning away at it's max pressure whenever idle,
that would cause excess noise from cavitation - the relief valve would
allow some fluid to circulate back to the tank under control. I'd
turn the pressure down a notch and see what happens...

If that works, might even try a second relief valve set far lower
with a ball or solenoid valve in front of it, for the majority of the
time when you don't need the press' maximum output tonnage.

(If I build a powered press, it'll probably use an Enerpac style
air-over-hydraulic pump, they're stone quiet when not in use, and they
creep nicely when throttled back... I have one with an old 3M MS2
cable splicing head attached, all I need is a high-pressure hydraulic
coupler to allow it's use elsewhere.)

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
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