[TheForge] hydraulics
Chuck Robinson
[email protected]
Thu Apr 17 12:29:01 2003
Hey Ed,
I've helped design and build 5 H Presses so far, most were made with surplus
cylinders with different termination connections. The critical thing to
remember is that 95% of the loading force is exerted in th push stroke. Very
little in the return stroke.
I'm sending you some photos of a model of the Hp and the 7" Diam cylinder
that will be used in the press under construction..
If I were to build a cylinder from scratch it's top end would be machined
flat to butt up against the bottom horizontal anvil cross members to take
the load and a smaller tab would project between these cross members and be
bolted to the members with a 3/4" grade 8 bolt. the tab bolt hole would be
oversize to allow some play in the return (pull stroke) the piston end would
but against a stop block welded between the bottom cross plates. The rod
would have a similar horizontal bolt hole with an oversized hole.
Remember that the frame vertical side pieces in my design slide in their
own massive bearing surfaces and resist any side loading forces.
In one of my discussions with Jim Batson , he said that to achieve maximum
strength , rigidity and eliminate misalignment, the whole sliding rectangle
could be cut from a plate of thick steel using a plasma track torch or
water saw.
If you have the large plate available that might be an option for you.
Chuck
----- Original Message -----
From: "Ed F" <[email protected]>
To: <[email protected]>
Sent: Wednesday, April 16, 2003 6:56 AM
Subject: Re: [TheForge] hydraulics
> Hi Chuck,
>
> So you pin the clevis of the cylinder between the plates and the barrel of
> the cylinder bumps out wider than the plates right? You sent me a picture
> like that a while ago. I was thinking of nesting the barrel between the
> side plates to save height, but that gets pretty wide. I'll re-think that
I
> think.
>
> The guy I spoke to said the same thing about the flow divider, as long as
> you don't forge off center. It makes sense -when the oil sees more
> resistance from one side of the tee, it will tend to go to the other. I
was
> thinking that might put some ugly twisting on the frame that would be very
> tough to predict and accommodate structurally.
>
>
>
> ----- Original Message -----
> From: "Chuck Robinson" <[email protected]>
> To: <[email protected]>
> Sent: Tuesday, April 15, 2003 10:57 PM
> Subject: Re: [TheForge] hydraulics
>
>
> > Hey Ed,
> > My press uprights will be 4"x1 1/2" inch bar stock so when the 1"x 6"
> cross
> > plates are welded on either side of the uprights there will be a 4" gap
> > between them. When I make my dies for drifting and punching the
receiving
> > die will be on the top cross plates to take advantage of the open space
to
> > pass the drift through.
> > You want to use as long a ram stroke as you can to permit working on
large
> > work stock and specialty die plates.
> > If you are having the cylinder custom made recommend about a 14" stroke.
> > Make sure that the cylinder head and rod connection ends use attaching
> > fittings that minimize the length need to connect to the press.
> > Also I like to build in a little slop in the attaching fittings to
> minimize
> > side loading on the ram seals when forging off center.
> > For what it's worth an old time hydraulics guy told me that if you use
> > identical cylinders,fittings and plumbing lengths and sizes the rams
> > shouldn't need a flow divider.
> > Chuck
> >
> > ----- Original Message -----
> > From: "Ed F" <[email protected]>
> > To: <[email protected]>
> > Sent: Tuesday, April 15, 2003 9:24 PM
> > Subject: Re: [TheForge] hydraulics
> >
> >
> > > Hi Chuck,
> > >
> > > I just checked into a rotary flow splitter - guy at the hydraulic shop
> > says
> > > they will start at about $500. Wheew, I think I'll look at doing it
> with
> > > one again. The inverted style or whatever you call it with the
cylinder
> > > below the work-surface pulling on tension bars may work ok for
punching
> if
> > > the top of the cylinder is put on blocks to allow for a horizontal
hole
> to
> > > push the slug out with. The blocks would eat up clearance to the
floor
> > but
> > > I was thinking of spacing the low cross-member pieces out so that they
> can
> > > clear the outside of the barrel. Ya know what I'm sayin?
> > >
> > > Ed
> > >
> > >
> > > ----- Original Message -----
> > > From: "chuck schaeffer" <[email protected]>
> > > To: <[email protected]>
> > > Sent: Thursday, March 20, 2003 12:11 PM
> > > Subject: [TheForge] hydraulics
> > >
> > >
> > > > To everyone interested in Hydraulics,
> > > >
> > > > Something I picked up from the Batson plans was looking at what the
> end
> > > product is going to be. Buying a piece here and there makes it very
> > > difficult to gain compatibility with all of the parts. I buy all new
> > parts
> > > due to having been burned on used stuff a couple of times. This also
> > allows
> > > you to match the parts to give you a better system. Having your plan
in
> > > mind you can pick up pieces as the funds are available.
> > > >
> > > > I buy quite a few things from the farm stores around here. Their
> prices
> > > are good and have it in stock or will order it for you.
> > > >
> > > > Marathon motors make single phase motors up and including 10 hp.
> > > www.marathonelectric.com
> > > > The prices they list are considerably higher than what I pay around
> > here.
> > > >
> > > > To hook two cylinders in parallel you will need to place a divider
in
> > the
> > > power side coming from the pump or it could be placed in the return
> side.
> > A
> > > rotary divider will give you the best results. There are other types
> out
> > > there that use slides to control the flow. Be sure that they are
50:50
> > > divider with balancing at one end or the other.
> > > >
> > > > I agree with Ralph about using the pumps at lower speed and half
> volume.
> > > Not only quieter but will give you much better pump life.
> > > >
> > > > Anyone using electric control valves, check for pressure relief.
> Those
> > I
> > > have used required an external pressure relief.
> > > >
> > > > Sorry I got a little wordy with this.
> > > >
> > > > Chuck
> > > >
> > > > Chuck Schaeffer
> > > > Metals Magic Shop
> > > > [email protected]
> > > > Ph. 608.798.4296
> > > > Fax 608.798.1940
> > > >
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