Subject: Re: used hydrolic press

From: [email-masked] (Dave Williams)
Date: 18 Dec 94 08:17:00 GMT

-> a common "shop " project for welding is to make a frame
-> to use a manual bottle jack as a press...this is very

 I have an Enco 12 ton press.  It's a Taiwan thing made out of metric
angle iron, with a huge bottle jack.  It worked fine for pressing
shafts, axles, and wristpins, but it met its match trying to take apart
an old tiller shaft.

 A neighbor gave me an old 5hp roto-tiller.  It runs perfectly, but he
hit a log and popped the chain off.  The chaincase is between the two
sets of tines, and the tines have to come off to split the chaincase.
No problem, right?  Except the tines were bolted to flanges on sleeves,
which bolted over the shaft.  The sleeves were rusted to the shaft.

 I managed to get the two outer sleeves off by dunking the thing in the
acid tank at the local engine rebuilder's, soaking it down with Break
Free, and then heating the whole mess red hot with the torch.  I managed
to rig the thing up in my little press, turned a mandrel on the lathe to
reach down inside and push on the shaft, and started pumping the jack.

 The press is rated, as I mentioned earlier, at 12 tons.  The sleeve
didn't go anywhere.  I jacked until the whole frame started to creak,
then heated the sleeve with the torch while it was under pressure.  Then
I tried alternating heat and cold, and finally left it overnight under
pressure.

 The next morning I soaked it all down with Break Free again, grabbed
the handle and started hanging off the jack handle.  After a few seconds
the jack got easy!  Yay!  I pumped away, then noticed the mandrel wasn't
going anywhere.  About that time my wife walked in and said, "is that
supposed to look like that?"  I looked up, and the crossbar over the
jack had bent up and out, split the ring that located the jack, and bent
the four upper pieces.  Whoops.

 I disassembled the top section.  The upper bar was four pieces of ~1/4"
mild steel laminated together by the end bolts.  I mashed it all back
flat and straight in my big bench vise, then MIGged it all around.  I
put the press back together and tried again.

 Pump.  Pump.  Pump.  Heat.  Break Free.  Ice water.  Pump.  Pump...
it's moving... it's moving... uh-oh.  The upper bar hadn't bent.  It
just pulled the bolts right through the 2mm steel straps!   Since I
didn't have any flat stock of convenient size handy, I welded some 1/2"
ID washers on both sides of each strap.

 Put it back together.  Pump, pump, pump.  Gotcha THIS time, you sorry
bastard... pump, pump.  SPANG!

 This time the top held.  The little pins that held the work table had
bent down, twisting the work table nicely, and letting the right side
fall to the floor, complete with tiller stuff.  When it bent the shaft,
it bent both right side press legs together until they touched.  It also
elongated the holes on both sides.

 I used a piece of all-thread and some nuts to jack the legs back out,
cut a couple of straps to brace the legs to prevent this from happening
again, but I haven't welded it up or bought new stock for the pins yet.

 To hell with it.  I didn't want a tiller anyway.  But that 5hp B&S
would make a nifty go-kart motor.

 The moral to the story:  just because it's a 12 ton jack, doesn't mean
it's a 12 ton press.

==[email-masked]=======================================
"Live to Flame - Flame to Live"    XJ900 TURBO   "Meet Jesus at 15psi"
Denizens of Doom M/C - rec.motorcycles usenet         DoD #978 xKotFAQ
=====================================================================-

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From: [email-masked] (-F.KERFOOT)
Date: Mon, 19 Dec 1994 15:50:47 GMT

In article <[email-masked]>,
Dave Williams <[email-masked]> wrote:
>...long, humorous story deleted...
>

How do you know you were only applying 12 tons? I have the same press,
or at least a close relative. Do these jacks have some type of pressure
release at their rated load? Otherwise, it seems you can simply keep
increasing the load until something breaks. I was toying with trying
to add a pressure gauge, which would (with an appropriate scaling)
measure applied force. It hasn't bubbled up high enough on the
priority list to get done yet. However, this may be a good time to ask
if anyone else has done it. Is there a particularly convenient place
to drill and pipe thread th body where it it thick enough to tolerate
this sort of thing? How easy is it to dismantle the jack, to allow
drilling and tapping without contaminating the hydraulic oil? I assume
the gauge pressure is going to be in the range of many thousands
of PSI (I don't know the diameter of the main piston to figure it
out). Can I get away with just pipe threading the gauge into a
tapped hole somewhere in the jack at these pressures (assuming the
place I drill and tap it is thick enough?

Frank Kerfoot
[email-masked]

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From: [email-masked] (James Kirkpatrick)
Date: 19 Dec 94 13:10:18 MST

Re measuring actual force, there was an article earlier this year
in either HSM or PIM on building a hydraulic load cell, though it
may not be beefy enough for this application.  I suppose you could
place the load cell between the jack and the beam, being careful to
secure it so it wouldn't "squirt" out of place.

Jim