When Harbor Fright came out with their air-over-hydraulic 20T jack, I swapped it out for the manual hyd jack the press came with. I think the only adaptation needed was to throw a 1/2" or so thick steel plate under the new jack which has a larger base plate than the manual jack. What a difference in operation! Instead of working up a sweat pumping that handle you just press the lever on a valve. Of course you need compressed air but the jack doesn't use much. I've used my converted HF press mostly for straightening things, occasionally to assemble things or power a crimping die, but everything goes better and faster and more accurately with the new jack. Safety is also better as you can be as far from the press as the hose length downstream from the trigger valve permits. I got nailed in the leg by a piece of shattered steel I was pressing and got a bad case of phlebitis from the deep wound, so I like to be at least a few feet from the press and preferably behind something while pressing. I hesitated posting this because it is such an obvious thing to do, maybe most everyone has either done it or read some post about it. In summary, the air-over-hydraulic jack conversion turns your homely HF press into a much more useful, more controllable, and potentially safer tool.
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