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Strongest for bending strength?

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  • Strongest for bending strength?

    I have a Friend (don't We all) Who needs a tommy bar. 3/8" diameter. What would be the best steel to use with no heat treating? Have access to all the common flavors of steel, 4140,1144,01,A2 etc. Medium bending stress. Would like it to last. Allen wrench type material would be nice but probably break the bank.
    mark costello-Low speed steel

  • #2
    Cut-off from extra long Torx key
    Location: Helsinki, Finland, Europe

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    • #3
      15" needed. Round wanted.
      mark costello-Low speed steel

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      • #4
        3/8" Thomson rod. https://www.thomsonlinear.com/websit...dard_shaft.php
        Kansas City area

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        • #5
          Without any heat threating:
          https://www.mcmaster.com/#standard-s...stock/=1a5lxbk
          High-Strength 4140 Alloy Steel Rods (ETD-150)

          With simple tempering at home oven: (temper at 500f for 1-2 hours)
          Hardened Tight-Tolerance Multipurpose O1 Tool Steel Rods

          edit: linking to mcmaster was fubar
          Last edited by MattiJ; 11-07-2017, 03:40 PM.
          Location: Helsinki, Finland, Europe

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          • #6
            I have one made out of the rod that goes on the end of a steering rack, it's not unbend able but it's fairly strong and as its off a scrap car, free.
            What it's made of I don't know
            Mark

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            • #7
              Go buy a 3/8" socket extension from HF. It'll probably out work any of the wet noodle suggestions so far.

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              • #8
                Scrap auto parts, got me thinking .... the rod from gas struts are about 3/8 , not sure if you can get to 15" though.

                Joe B

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                • #9
                  You know, I've always wondered just what combination makes a good pry bar.

                  I've got a 5 foot Pinch bar that has served me well for more than 40 years. I don't think I can ever bend it. Then there are those tire iron. The old "brown ones" are straight as the day they saw light. The newer flat and plated ones have been bent and straightened many times.

                  Is it a combination of hard skin and tough core? Or is it just tough through and through?

                  I wonder?

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                  • #10
                    Originally posted by CCWKen View Post
                    Go buy a 3/8" socket extension from HF. It'll probably out work any of the wet noodle suggestions so far.
                    Crossed my mind also but those are probably thicker than 3/8"

                    the hardened O-1 from mcmaster is quite far from "wet noodle"
                    Location: Helsinki, Finland, Europe

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                    • #11
                      Originally posted by CalM View Post
                      You know, I've always wondered just what combination makes a good pry bar.

                      I've got a 5 foot Pinch bar that has served me well for more than 40 years. I don't think I can ever bend it. Then there are those tire iron. The old "brown ones" are straight as the day they saw light. The newer flat and plated ones have been bent and straightened many times.

                      Is it a combination of hard skin and tough core? Or is it just tough through and through?

                      I wonder?
                      Optimum for pry bar use is probably slightly softer core. But its more than than, the heat treatment has to be done correctly and steel needs to be suitable grade.
                      Like good hex keys that are ~60 HRC hardness and still not overly brittle.
                      Location: Helsinki, Finland, Europe

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                      • #12
                        4140 is a "thru hardening" steel. Thomson rod is a "case hardened" rod--the center is still malleable. Only the outer surface of the rod is hardened.
                        Brian Rupnow
                        Design engineer
                        Barrie, Ontario, Canada

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                        • #13
                          Originally posted by CCWKen View Post
                          Go buy a 3/8" socket extension from HF. It'll probably out work any of the wet noodle suggestions so far.
                          This would be my first choice as well for a readily available and usually nicely finished piece of tough steel. Not sure how long it has to be but I've got 3/8 extensions that are quite long, several 24" and 20". Not counting the ends, the shaft diameter is less than .350", probably 11/32".
                          Home, down in the valley behind the Red Angus
                          Bad Decisions Make Good Stories​

                          Location: British Columbia

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