I took on a challenge recently. It is a Reed 305 1/2 fixed-base, swivel-jaw vise that had been buried in mud beneath a fallen-down barn for many years. Judging from the condition, at least a decade. Every moving part was stuck solid, and there was a thick coat of rust on almost every surface. The one exception was the screw, which was somewhat protected, but which had some rust showing.
To start the disassembly, I made a nest of fire bricks to hold the heat from a propane weedburner torch aroung the vise. I directed the torch at the screw and nut through the tail end of the slide
Once the screw freed up, I heated the main casting to about 600° which broke the rust bond at the parting lines between the slide and the main casting.
It did the same for the joint between the main casting and the swivel jaw.
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I cleaned up the slide surfaces with a wire cup wheel, followed by a Scotch Brite stripping pad on a 4-1/2" grinder. This was to prevent friction between the slide and the main casting when the slide was forced out. I heated the end of the screw and beat on the end of the handle with a 2-pound copper-faced hammer to free it up. I had to work it back and forth while cleaning the rust off the exposed surfaces to get it freed up.
My setup for removing the slide was a 10-ton short porta-power ram in a puller configuration. I used scrap and salvaged material to build the parts. Two pieces of 1/4x2 angle iron formed the arms, with 3/4-10 redi-rod for adjustment and 3" long pieces of 1x2 flat bar for the "jaws" of the puller. I had built a strongback from 4" U-channel previously that I use for pressing. I use it with my 30-ton rams, so I made it adjustable for the gap so I can use it with up to 1-1/4" redi-rod. I narrowed it for the 3/4 rod in this application. Pieces of scrap plate spread the pressure of the ram against the strongback and the end of the vise slide. I put an estimated 6 tons of force on the ram and then heated the main casting with the weedburner.
It again took about 600° to break the slide loose, but it started moving. I had taken up the backlash in the screw, so I wasn't pushing against it. Once it started moving, the weight of the handle caused the screw to unscrew. When I set up the puller, I used wood blocks to support everything in position until I put pressure on the ram. Once under pressure, I removed the blocks because of the torch heat.
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The C-clamp on the "jaws" is to keep them from spreading in case there was flex in the setup. Notice that the redi-rod is almost perfectly in line with the pressure point of the "jaws" to help prevent slippage. You can also see how the plate washers transfer the pressure to the strongback. The nuts and washers were the only new parts of the setup.
To be continued.