I scrounged a small press frame some time back, but it was missing the hydraulics, so its been languishing in the back 40 for sometime, and last week I decided to experiments a bit. Leigh Knudsen told me one of his buds used a bottle jack, by simply turning it upside down and adding an outside reservoir. So I tried it.
Having a small 6 ton import (Allied) bottle jack surplus, I used it.
I bolted a 3/4" plate to the underside of the top of the press frame and machined a pair of brackets to hold the jack upside down against the plate.
I then pulled the filler plug on the jack body, and tapped it to 1/8" pipe, and installed a hose barb, with a bit of hose running upwards to a reservoir made from a piece of 1' hose clamped to an upright on the top of the press frame. Oddly enough..I didn't have anything suitable for a reservoir around. (making notes to scrounge...), and filled both the jack, and the reservoir with hydraulic oil.
Now came the big problem..bleeding all the air out of the jack. I tried various methods, and finally settled on two ways. Pulling the valve out (be careful, there is a ball check valve that will pop out) and cycling the ram by hand, brought out a lot of air. (cover the hole with your finger on the suck stroke). I repeated this a dozen times or so, until I stopped feeling that bouncy bit in the ram as it pushed air. I also drilled and tapped a 10-32 hole near the top of the bottle and standing the jack upright, pushed down on the ram and a fair more bit of air came out, then sealed the hole with a screw and a bit of thread dope.
I took a big washer, unscrewed the adjustment screw from the end of the ram, put the washer over the end of the ram, and replaced the screw. A hole drilled in the washer got one end of a heavy screen door spring leading to bolt inside the top of the press frame, to retract the ram when pressure was released.
I like the ability to use the screw at the end of the jack ram for fine adjustments before pumping it up, and its handy if your blocks are too short and saves you from having to scramble around looking for another block or three.
The only downside to doing this..is the pump handle is on the left, and you have to pump UP wards on the power stroke.
My particular jack drips a drop or two of oil from someplace (probably the pump seal) every day, but its not a big concern to me.
Oh.. a further note..you can make your reseviour out of PVC pipe or whatever, but make sure its capacity is a lot bigger than you think you will need. As I was bleeding air..I was filling the resiviour, and found that when you retract the ram..it moves a LOT of oil into the resivior..more than my first attempt would hold.
When I get around to it, Ill put a bigger jack in the frame, modified as above. The little 6 ton one has already been handy as hell.
And it looks a lot better than the standard upright jack with a stinger welded to its ass end and a bunch of springs. Shrug.
"To be civilized is to restrain the ability to commit mayhem. To be incapable of committing mayhem is not the mark of the civilized, merely the domesticated." - Trefor Thomas