Subject: Arbor Press Disappointment

From: [email-masked] (Stuart Friedberg)
Date: Wed, 30 Jun 93 02:54:18 GMT

I need some (more) advice.  Not too long ago, I got a 3-ton arbor
press, made a roller stand for it, and didn't do anything with it.  :-)

Last weekend, I made a couple of crude broaches and *tried* to
use the press push them through.  The little girls who periodically
invade my shop (and ask things like "Why do you have a box of rubber
bands in your garage?") were delighted to see a 200 lb supposed adult
hanging from the end of a 24" lever with his feet in the air, growling
and muttering things under his breath.

Because the workpieces and broaches were short, I was able to stick
them in my heavy 5" bench vise.  I was pleasantly shocked to discover
I could push them through without a cheater, and could very easily
crank the vise handle with a cheater.

I haven't measured screw and pinion diameters yet, but I did a
rough estimate, and I'm getting 5000 lbs force from the arbor press
(I'd get more if I weighed more) and roughly 30,000 lbs force from
the vise with no cheater assuming an 80 lb force on the vise handle.
Does 15 tons sound right for a heavy vise?  (As a sanity check, I
was utterly crushing and destroying a 2" oak backup piece I was
using.)

Here's where the advice request comes in:

For my pressing needs :-), I need a height-under-column and throat
roughly comparable to a 3-ton press.  But it looks like I need
something in the 15 to 20 ton range.  All the cheaper hydraulic
presses I've seen have strokes so short that I would have to move
the bed once or twice in the course of a job.  (11" is a common
keyway broach length.)  Can anyone suggest an under $300 solution
that doesn't require dropping things on my feet in the middle of
a single stroke?

Can I simply take a surplus cylinder with a 4" to 5" bore and a
long stroke and make a copy of the typical cheap hydraulic press?

I gave a little thought to mounting a hydraulic cylinder above the
existing ram in the 3-tom press.  Is there enough design margin in
the frame of such a press to avoid snapping off under 40,000 lbs
force?  (It's a Jet, if that matters.  It looks pretty beefy, but
I have no idea what the strength of this particular lot of cast
iron is, and it makes a difference.)

Stu Friedberg ([email-masked])

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From: [email-masked] (ron ginger)
Date: Wed, 30 Jun 1993 12:45:15 GMT

In article <[email-masked]>, [email-masked] (Stuart Friedberg) writes:

|>Last weekend, I made a couple of crude broaches and *tried* to
|>use the press push them through.
.....
  Can anyone suggest an under $300 solution

|>Stu Friedberg ([email-masked])
|>

I have a 3 ton arbor proess, of the rack and pinion type. I have a few keyway broaches and have no trouble pressing them through. In fact, in my first attempt
I drilled a too small hole in teh backup plate and even keyed that along with
the hub. 

Improve your broach and you shouldnt need tons of force.

Was this a single tooth broach, or did you make a multi-tooth, like a commercial
broach?

ron  ginger

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From: [email-masked] (Wm. W. Martin)
Date: Wed, 30 Jun 93 16:15:56 GMT

In article <[email-masked]> [email-masked] (Stuart Friedberg) writes:
>From: [email-masked] (Stuart Friedberg)
>Subject: Arbor Press Disappointment
>Date: Wed, 30 Jun 93 02:54:18 GMT

Beware of overloading an H-frame press...they tend to "spring" a lot, and if 
something under the ram lets go suddenly, it may depart the scene with enough
kinetic energy to go right thru the side of your house, and most anything
else in the way...

[email-masked]