Not a stupid question, usually a rubber plug on the side of the bottle. Fill with fluid to the opening.
I have used a bottle jack in other than the normal position. A remote reservoir large enough to hold the fluid when collapsed and large enough to supply the fluid when fully extended.
Remember though, you will need springs to recompress the cylinder. Porta powers work good for Hydraulic Presses.
As another poster said, why invert it. Turn it right side up and have it push against the top of the frame while driving down a plate with a ram on it. 2 heavy side rods to support the whole thing to the top of the press frame. Go to Harbor Freights website and do a search of Hydraulic press so you can see the concept?
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Gunner wrote in news: email@example.com:
Greetings Gunner, I got one 'o' dem upside down type bottle jacks dat were modded by me. An' iffn I kin do it any one can. You'll be able to do this in your sleep. Push the ram all the way in. Pull the rubber plug and drain the oil. Remove the big nut that holds the outer case on. Remove the outer case. Inside the casing is another tube into which the ram slides. Pour a little oil into the slight depression that surrounds the inner tube. Tighten the valve and operate the pumping piston slowly. You will notice oil being drawn into a little hole. Find a piece of metal tubing that is slightly larger than the hole. Cut this tube so that it is as long as possible without hitting the outer casing when it is replaced. Open up the intake hole so that it is the size to be a press fit for the metal tube. I bought some SS tube 1/8 OD for another project at the hardware store. They sell this stuff at hobby shops too. You could use brass tubing as well and it would be cheaper. I took apart the whole jack to make sure I got all the chips out but if done carefully you could probably get away without doing that. Press the tube into the base casting. Tap the rubber plug hole to accept a pipe plug. I did this because the rubber plug didn't seal real well. Re-assemble the jack. Stand jack up in the normal position and fill with oil till it runs out the filling hole. Invert jack and cycle through full extension and retraction a few times to bleed. Now you're done. There is no provision to pump these jacks closed. I think I've figured out how to put a return spring in the piston but it would require boring a hole in the base casting to make a spring housing mount and the housing would need to be able to withstand the jacking pressure. The inner tube has a tiny hole at the top to relieve pressure when the jack is at the end of it's stroke. This hole can't be used to drive the ram back into the tube. Anyway, I'm just starting to think outloud.. Good luck ERS
Ive seen modified jacks, and with the 15 ton frame I have, Id just as soon not have all the various plates, and whatnot sticking out all over. Nearly all of the presses I see, look like kludges. Shrug..and you loose the fine adjustment of the threaded extension at the end of the ram.
A simple pair of springs, on either end of a bar, with a hole drilled in the middle to pass the screwed ram extension, pulling upwards on the end of the ram is much cleaner and neater than all the other crap sticking out every which way.
I found a site with good instructions on how to add an external pressure gauge to a bottle jack
And thought this would be a nice addition
The original press was set up with a portapower type of jack, with the power unit on the side, but unfortunately, the original owner used the unit on another project, so I only have the frame.
Unless someone has a portapower collecting dust for very cheap, or trade for stuff..a bottle jack is what I gotta use. Shrug.
No one so far has indicated exactly how to fill a bottle jack.
Is it done with the jack upright or inverted, or laying down? Is it down with the ram in or out?
"The British attitude is to treat society like a game preserve where a certain percentage of the 'antelope' are expected to be eaten by the "lions". Christopher Morton
Set the jack upright. Retract the ram fully. Remove the filler plug. Fill with jack oil to the level of the filler hole. Replace the filler plug. Jack something up to the full travel of the ram. Retract the ram fully. Remove the filler plug. Fill with jack oil to the level of the filler hole. Replace the filler plug.
If the jack has been disassembled repeat the above until all air is out of the cylinder. I dont't now if inverting the jack will help remove air, but it may as the piston seals the uppermost part of the cylinder. I would try extending the ram, and inverting the jack while retracting.
This design may have some or all of the attributes you find objectionable, but it's worked well for me for at least a decade. I wanted a small, lightweight bench-mount 12-ton press. I didn't see any commercial offerings that fit my bill.
The fine screw adjustment is available at the top of the ram but I've never had occasion to use it. The machined and cross-drilled Chevy truck axel ram enables fitting of a variety of shop-made end effectors, as hex broaches made from Allen wrench bits and hard Phillips head screwdriver bits that mash a very servicable head in stock suitably center-drilled and captured on the table. Another shop-made tool mashed bits of copper tubing into flat washers suitable for the fuel-injection fittings on the several VW Rabbits I was keeping operational at the time for myself and my kids at the time.
There isn't a drop of oil on the bench after a decade of occasional use, The bottle jack is an import, 12 bux or so from wherever I got it. Might have been K-Mart though it doesn't have a Martha Stewart logo.
I called it good after a first test pressing out a U-joint bearing. I pulled the handle harder than I thought should be necessary though nothing was flexing, thought I'd built a NFG press until there was a POW as the needlebearing departed the housing as the press was politely but firmly asking it to do. I'd forgotten to remove the circlip that held the bearing in place. Oopsie!
: it. Might have been K-Mart though it doesn't have a Martha Stewart : logo.
: I called it good after a first test pressing out a U-joint bearing. I : pulled the handle harder than I thought should be necessary though : nothing was flexing, thought I'd built a NFG press until there was a : POW as the needlebearing departed the housing as the press was : politely but firmly asking it to do. I'd forgotten to remove the : circlip that held the bearing in place. Oopsie!