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Arbor press tonnage?

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  • #31
    I don't believe the 40 lb thing, I have seen a few arbor presses, and it don't work.

    take a 1 ton press. 2000 lb force.

    pinion is about 1.5 inch diameter. so lever arm is 3/4 inch, or 1500 inch lb. Might be bigger diameter, which makes it worse.

    Lever is about 15 inches long, maybe. Might be shorter.

    Say that gives 100 lb force required at the end of the lever, or somewhat more at the center of your hand when holding it.

    With friction and "hand width allowance", might be over 130 lb force on the arm required for 2000 lb force at the ram.


    • #32
      <font face="Verdana, Arial" size="2">Originally posted by Evan:
      Hmmm... A very simple high capacity scale may be made with a chunk of steel with a hole of 1.129 inches diameter and a similar sized piston with O ring to seal it, oil filled. Then use a standard pressure guage in the side such as used on an oxygen tank up to 2500 psi. It will read weight directly on the guage in pounds.</font>
      That's very interesting. Can you explain the math to this mathematically-disinclined person?

      I have a few spare gauges, I might just whip up a piston like that, and see what happens. I've always wondered what sort of force I could apply in the big bench-vise as well...

      Doc's Machine. (Probably not what you expect.)


      • #33
        A hole of 1.129 inches diameter has an area of one square inch, hence the guage will read in pounds directly. Scales like this are used to weigh aircraft when doing a weight and balance check.
        Free software for calculating bolt circles and similar: Click Here


        • #34
          They are called "load cells". Very easy to make. Sherline sells them.


          • #35
            Cutting to it. A tonnage rating is usually nominal - just a name. The press may or may not exert a ton of ram force using ordinary effort.

            Those cheap import arbor press frames are pretty stout. I'd think the rack or pinion would fail long before the frame broke. A 1 ton arbor press with a 5 ft pipe cheater on the handle might go 3 tons or more before you deform/break a tooth.

            .... dewwwwd!

            [This message has been edited by Forrest Addy (edited 08-19-2003).]