- Jan 5, 2012
- Reaction score
How does it compare to one of those rack and pinion arbor presses? I had the impresson that they are relatively expensive.Today I converted an old hydraulic car jack and some rest material into a shop press.
No more pressing bearings and dowel pins using the bench vise, but a proper and stable vertical press.
It's funny all this should come up but I'm actually designing/building a 30T press at the moment. It's another guy's core design which I really liked just for it's rack/shear-proof nature. The main web is 1" thick plate. He cut out and welded up the 750lb frame as I can't weld 1" plate with my MIG and I'm designing/building the hydraulic system. It's a bit of a money pit but that's because while it's 30T it's also going to be fast too so the hydraulics & power are large. Amongst other things it will be for forging welding Damascus so speed is of the essence. It's also foot-pedal operated to keep your hands free for handling the hot metal. I will say it's been a tremendous learning experience about hydraulics....and financial planning. ;-D It should keep me busy for the summer.With the icon of Wie E. Coyote, I can only imagine!
I seriously doubt that I've ever gotten anywhere near 20 tons in actual pressure applied. But even at less than 20 tons, it is quite amazing to see a solidly-welded structure racking into a diamond shape ... definitely not what one wants.
Rack and pinion or eccentric press gives better feel since there is a direct mechanical link, where hydraulic gives you more brute force. I would love to have a small rack and pinion one day, but indeed price is rather high. For delicate jobs I will continue to use a small 2 inch wide vise to press tiny pins and bearings.How does it compare to one of those rack and pinion arbor presses? I had the impresson that they are relatively expensive.
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One other note: the smaller rack and pinion style does come with one inconvenience that should be mentioned - it can be a bit of a pain to get the arm positioned optimally. Larger / commercial presses of this sort often have a clutch and handwheel mechanism that allows quick positioning of the ram and allows one to pull down on the arm, lift it up for more travel, and pull down again. (Hopefully that made sense ...)The rack and pinion type can be very convenient for pressing bushings in / out. If they are larger, they may work for broaching keyways - the smaller ones almost certainly won't be up to that task. And the opening of the throat can be limiting, again depending on the size.
In general, I reach for my small rack & pinion whenever the work is within its capacity, because it will be quicker (since my hydraulic is manually pumped), but it sure is nice to have the larger capacity (both size and force) when really needed.
Yes, agreed!Great ideas guys, but please note. PRESSES are designed to be STIFF under load. Not "just strong enough". It is the stiffness that keeps both anvils in line and parallel, to prevent the job from slipping. I have an hydraulic jack, pump needs fixing (it was a gift) but worked out appropriate steel for a stiff frame, and I would not be able to lift it!
I have pressed bearings out of motorcycle crankcases using a car jack between 2 walls in a stairwell, and inside a door frame. (We have brick-built buildings in the UK, not cheap wooden huts).
For model stuff, my 4in. Engineers vice does everything.....
But we'll done if the press does your job safely. The last thing you want is slippage to cause a broken casing, bent shaft or something .
Makes sense to me. I use my 3-ton arbor press daily as a cat-food-can crusher (I have five cats, so lots of little aluminum cans that I melt down periodically), and at the outset I had to adjust the arm to provide the optimum clearance and stroke. If I had to adjust it frequently, It would indeed be inconvenient, but I seldom need to move things.One other note: the smaller rack and pinion style does come with one inconvenience that should be mentioned - it can be a bit of a pain to get the arm positioned optimally. Larger / commercial presses of this sort often have a clutch and handwheel mechanism that allows quick positioning of the ram and allows one to pull down on the arm, lift it up for more travel, and pull down again. (Hopefully that made sense ...)
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