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El Cheapo Self Centering Vises

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  • El Cheapo Self Centering Vises

    I asked about this sometime back and I seem to recall the cheap ones like this were not reported to repeat all that well.

    https://www.grizzly.com/products/Gri...al-060516_box4

    How bad was not that well? A couple thousandths? A couple hundreds? A couple inches?

    When I drill hinge pin holes in molds I've got them laid out so the position isn't all that critical. The closer to "prefect" it is the prettier it looks when open, but it will open and close just fine with it pretty far off. A few to several thousandths might not even be noticeable to most people. If I could drop a 1" thick mold in and then go to a 1.5" or 2" and always be within a few thousandths of the original located center I'd be pretty happy with it.

    I'd remove the swivel base and machine off those stupid ears so I could just drop it in a vise on the table of course.

    I've been doing more and more hinged molds lately, and the time to setup and drill hinge pins adds up. Well, along with setting alignment pins, and putting on handles, etc, etc.

    I'm at that point where I am exploring acceptable tolerances in order to maximize productive use of time. Hinges can be sloppy if alignment pins are close. Alignment pins go in faster if a starting lead and a press fit are both machined in before it comes out of the vise. My bigger machines are faster for major roughing, and if I plan the job well the high speed machines can do the detail work faster, etc etc etc...
    *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

  • #2
    I would think that for parts that were the same size they’d repeat well, but maybe not so much going from a 1” part to a 2” part. I wouldn’t mind having one myself.

    I made a hydraulic self-center vise to hold 4” high pressure gas cylinders up to 100 lb propane tanks for removing the valves and hydrotesting. One jaw was driven closed by the hydraulic cylinder. A hefty wire rope that attached to that jaw passed around a grooved pulley and pulled the other jaw inward. A threaded stud crimped on both ends of the wire rope allowed adjusting of the center location. It worked really well and a big spring pushed the jaws open.

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    • #3
      haven't used one but i would imagine most of the problem is the screw moving relative to the housing. there is variable and unpredictable friction between the two jaws and the baseplate, so if the screw is free to slip around then you'll have as much repeatability as there is slop in the screw location.

      i would imagine it would be very easy to locate the screw positively using a variety of methods. as simple as cutting a groove into it and using a set screw to drive a plug into the groove. or simply improve the existing mechanism to capture the screw.

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      • #4
        I've been thinking about this some. Considering making my own just for the experience.
        *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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