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Can anyone tell me about this rod shear?

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  • Can anyone tell me about this rod shear?

    I have this old lump of iron that I'm trying to get back into usable shape:

    It's clearly a rack-and-gear operated rod shear, says "Armstrong Blum" on this side, and "Marvel" on the other. Googling those terms brings up lots of references to Armstrong-Blum, who still apparently make ironworker-style hydraulic shears, but no data on this old thing.

    One person told me it was meant for rebar, which I could see, but the little hole of the five (slightly bigger than 1/4") seems kind of dinky for rebar.

    It's seized up and I'm applying copious amounts of both WD-40 and savage beatings in order to try and free it, and the lever collar is badly broken. I think it'll be repairable if I can get the big cam to break loose without damage (any suggestions?) but I'm wondering about the history of the piece.

    Anyone ever seen one or used one like it? Was it, in fact, meant for rebar?

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

  • #2
    Electrolyse it with washing soda, that should free everything up,savage beatings will just deform things, better use an air hammer hooked up to your air compressor and a sacrificial piece of metal for the tip of the hammer to hit.
    if you do the above it will free up.
    Last edited by thistle; 04-03-2007, 10:24 AM.


    • #3
      Problem is, the seized part is the axle shaft in the body casting. Any rust-removal dip or bath won't touch that. I'm toying with the idea of drilling/boring out the axle- making a replacement would be relatively easy, it's just bar stock with a shoulder at one end and threads at the other. (Gotta be pretty good steel though...)

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


      • #4
        I have one of those.

        They were meant for general purpose shearing of round bars, not rebar. I wouldn't use it for rebar, rebar can be nasty material to shear, no point in ruining the shear blades.

        The largest capacity of mine is 5/8" and that hole is slightly damaged.

        I called Armstrong or Marvel (can't remember who) about sharpening the blades or getting replacements. The complete shear units may still be available, but not the blades alone. The guy said to use it and throw it away when it's not usable anymore. That was a surprising attitude.....

        The way the blades are mounted if they were surface ground to remove the bad, rounded over area it'd be hard to re-shim to compensate.

        In short, these are okay shears, but on great.


        • #5
          the shaft will work free with electricity, just be patient leave it on for a few days, try it the another couple days.


          • #6
            Nice piece of history. When I found my 1920 Pexto circle cutter, it looked like it spent the last 50 years at the bottom of a lake. I soaked it in diesel fuel for a week. When I pulled it out, everything moved. From there it was just disassembling and cleaning. I reground the cutting wheels and it works as good as new. That looks small enough to hang in an electrolysis tank for a few days or a week.

            Nice find!


            • #7
              You may have better luck with something other than WD-40, too. I don't think it's the greatest thing for breaking rust.
              Try to make a living, not a killing. -- Utah Phillips
              Don't believe everything you know. -- Bumper sticker
              Everybody is ignorant, only on different subjects. -- Will Rogers
              There are lots of people who mistake their imagination for their memory. - Josh Billings
              Law of Logical Argument - Anything is possible if you don't know what you are talking about.
              Don't own anything you have to feed or paint. - Hood River Blackie


              • #8
                There used to be three or four companies that made these- they are properly called a "rod parter" and were usually made in three sizes- yours is the smallest, and the biggest ones were powered.
                Not for rebar, but round bar only.

                Di-Acro still makes one, I believe. Theirs is a newer, compound leverage design.



                • #9
                  I'm going to go out on a limb and guess it was made by Armstrong & Blum Mfg. Chicago, Il.

                  I'm kinda partial to Kroils for unrusting something? Is that a word? uh oh
                  "The men the American people admire most extravagantly are the greatest liars; the men they detest most violently are those who try to tell them the truth." H. L. Mencken

                  "All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."

                  "When fear rules, reason and logic are ruled out."


                  • #10
                    The blades in this type of shear can often be broken...I would take it easy on the pounding you are doing.



                    • #11
                      Have that identical model at work,still use it often to lop off 100's of 1/4" rods.


                      Still sells them,notice the price and the parts cost"Bench-Mount Rod Cutters" page 2261.

                      Worth the effort to free it up and try them out.I have had luck getting stuck things loose in a electrolyisis bath using muriatic acid in place of washing soda.Unit must be free of oil though.

                      FWIW,ours is very oold and used,but still cuts good.I sharpened it once using a Dremel tool and a Chainsaw sharpening stone after getting it apart.
                      I just need one more tool,just one!


                      • #12
                        Hi There,

                        I'll second the use of Kroil (made by Kano Lab.s). It is the best penetrating
                        oil I have ever used. My second choice would be PB Blaster. WD-40 just
                        doesn't creep into tight, rusty places that well.

                        Apply liberally; tap (NOT beat) around the joint and let work for a day or two.
                        Re-apply some now-and-then during the two day soak (a little more tapping
                        will help too). It should loosen-up

                        Good Luck!
                        -Blue Chips-