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Arbor press tonnage?

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  • Forrest Addy
    replied
    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).]

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  • Thrud
    replied
    They are called "load cells". Very easy to make. Sherline sells them.

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  • Evan
    replied
    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.

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  • Doc Nickel
    replied
    <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.

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  • Oso
    replied
    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 15.......so 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.

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  • Evan
    replied
    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.

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  • docsteve66
    replied
    The press force?
    A five ton press should be able to exert five tons of force (pressure) (NOT Psi) at the working end. I have measured no arbor presses, but many hydraulic jacks. All most without exception, 40 pounds at the end of the handle develops the pressure required to lift the maximum load. 40 pounds force from a man appears so often in legal restrictions (or used to appear) that i suspect 40 pounds on a arbor press will develop the rated force also. It would be easy to reverse engineer: figure the mechanical advantage by gear ratio and lever arm length, set the ratio to the "rated force" and see what the input would be. Then you have to guess at the engineers "safety factor". I know hydraulic jacks rams have "O" rings that in some cases exceed 10,000 psi when operating at max load. Smaller jacks with big rams are rated at lower pressures. I used to routinely overload the jacks by calculating the load that would be required to reach the pressures I felt they could stand. i never had a jack fail, and i overloaded them by a factor of five or more FOR SMALLER jacks. I have never (knowingly) exceeded 20,000 PSI at the ram. I pucker when i exceed the 10,000 PSI figure (which I consider to be a conservative, safe figure)
    Steve

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  • lynnl
    replied
    Gag me with a fork. 'er is that a spoon. ...whatever.

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  • Guest's Avatar
    Guest replied
    .

    [This message has been edited by pgmrdan (edited 03-08-2004).]

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  • Dr. Rob
    replied
    Kenc! All right, a fully accurate obsevation that I am generally in agreement with, along with the rest of this thread.

    BUT BUT BUT

    I meant it. The handle is indeed a lot like four feet long. Maybe it is 3'8", or 4'2". I don't know since it can't be seen from here.

    So it is indeed approximately, similar to, or LIKE four feet long.

    Sorry.

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  • Evan
    replied
    Dvideo,

    He did accomplish that. He should have said "Ich bin Berliner", "I am from Berlin/a Berliner". He said "Ich bin ein Berliner", Meaning actually "I am a donut", or, considering his political importance it would be construed in the context of, "I am THE donut". I suppose this may have had the Easterners scrambling to figure out if this meant something like "I am the BIG cheese" or only meant that he needed to execute his translator.

    [This message has been edited by Evan (edited 08-13-2003).]

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  • dvideo
    replied
    What Kennedy really said was... "I am a (popular) jelly donut"... which greatly confused the W. Berlinrers and seriously trouble the E. Berlinners - "This jelly donut has nukes!!!"...

    I guess if you cannot intimidate them, confuse them... or even better.... worry 'em...

    -- jr

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  • Evan
    replied
    Mأ¥ske i denne omgang=Danish=Perhaps I am this time

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  • kenc
    replied
    Doc,
    Sorry.
    It's in "Dr. Rob"s follow up to your post.
    Dr = Doc.
    My fault for confusing you!
    Ken

    [This message has been edited by kenc (edited 08-12-2003).]

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  • Thrud
    replied
    Doc
    Yeah...!

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