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Why are hard wire cutter always 2 "V"s rather than bypass?

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  • Why are hard wire cutter always 2 "V"s rather than bypass?

    I want to make a small hard wire cutter, and thought using carbide inserts in a lightweight frame would work. What is the reason these cutters, I have a number of different designs, are always "V" jaws?
    Location: Jersey City NJ USA

  • #2
    Ever cut something hard with scissors? What happens? The item being cut swivels 90 degrees, and forces the jaws apart.

    allan

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    • #3
      I think the force needed to cut the same wire goes up tremendously with bypass cutters..

      I have these two klein wire cutters. NOT for hard wire but I have used them for hard wire and they did cut, didnt do the scissor thing. But it was much more difficult compared to a similar sized "V" type cutter.

      Also the shearing type cutter blades are more easily damaged due to the thin blade. JR

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      • #4
        Or just get a pair of aircraft cable cutters.

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        • #5
          Originally posted by JRouche View Post
          I think the force needed to cut the same wire goes up tremendously with bypass cutters..

          I have these two klein wire cutters. NOT for hard wire but I have used them for hard wire and they did cut, didnt do the scissor thing. But it was much more difficult compared to a similar sized "V" type cutter.

          Also the shearing type cutter blades are more easily damaged due to the thin blade. JR

          We used those ones on the left at work since we had to cut quite a bit of 5OO MCM aluminium and copper conductors; worked like a treat especially in cramped quarters. One day some lazy butt plug tried to cut ACSR with it and buggered the cutting edge royally. Expensive foul up just because he was too lazy to walk a few feet and get the correct cutters.
          Location: Saskatoon, Saskatchewan, Canada

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          • #6
            Originally posted by no704 View Post
            Or just get a pair of aircraft cable cutters.
            Why would I destroy my nice aircraft cable cutters on hard wire? If V cutter inserts were available I wouldn't be asking, but I want to use inserts in a light as possible aluminum frame. It's an emergency tool, not a daily use tool.

            Most of the issues I've seen using steel dykes on wire is the blade is tapered thin and the jaws are too soft. I think the cutters on spring forming machinery I've seen are bypass not V. If hard inserts with little or no relief were used, it would be very strong and hopefully not spall or chip.
            Location: Jersey City NJ USA

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            • #7
              A shearing action cutter is used for hard wire because a pair of sharpened edges coming from opposite sides, like standard diagonal wire cutters, will rapidly become notched.

              But why do they have Vee notches? Well, the best shape would probably be a pair of semicircular notches that are the exact size for the wire size. But then, you would need a separate pair of notches for each and every wire size. A Vee shaped notch will fit a range of wire sizes and still provide at least two points of contact instead of the single point that a simple, scissors type design would. So the Vee is an easy to make compromise between the straight scissors edge and a form fitting, semicircular notch.

              I think you are going to have a problem finding a carbide that will not chip and crack on hardened wire to make your cutters from. HSS or carbon steel may be a better material, hardened of course. And probably tempered to some degree. Gonna take some experimenting. And I don't know if aluminum will provide the strength needed to resist the tendency of the blades to separate on the hard wire.

              Personally, I prefer to use abrasive wheels for cutting hard wire. Dremel is your friend.
              Paul A.
              SE Texas

              And if you look REAL close at an analog signal,
              You will find that it has discrete steps.

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              • #8
                Originally posted by Paul Alciatore View Post
                A shearing action cutter is used for hard wire because a pair of sharpened edges coming from opposite sides, like standard diagonal wire cutters, will rapidly become notched.

                But why do they have Vee notches? Well, the best shape would probably be a pair of semicircular notches that are the exact size for the wire size. But then, you would need a separate pair of notches for each and every wire size. A Vee shaped notch will fit a range of wire sizes and still provide at least two points of contact instead of the single point that a simple, scissors type design would. So the Vee is an easy to make compromise between the straight scissors edge and a form fitting, semicircular notch.

                I think you are going to have a problem finding a carbide that will not chip and crack on hardened wire to make your cutters from. HSS or carbon steel may be a better material, hardened of course. And probably tempered to some degree. Gonna take some experimenting. And I don't know if aluminum will provide the strength needed to resist the tendency of the blades to separate on the hard wire.

                Personally, I prefer to use abrasive wheels for cutting hard wire. Dremel is your friend.
                Paul, I'm afraid I did not make myself clear. By "V", I mean the shape of the blades in cross section, like a typical bolt cutter, rather than bypass or shearing type cutters. All of my small hard wire cutters are that configuration. I'd never be able to do all the spring and wirework I do trying to Dremel it! Small cutters like a Knipex do the job great, or even a $10 8" bolt cutter will get by. I'm just looking to do it smaller and lighter. I'm under the impression hardening steel to the level of bolt cutter jaws without it shattering in use is not easy.
                Location: Jersey City NJ USA

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                • #9
                  Cutting hardened steel, doesn't the two V's indent the wire, breaking the wire in half before the V's make contact? so the angle is a compromise between what holds up and what cuts the wire with less force.

                  you could cut a 1/4" square HHS lathe bit, make two pieces half inch long. mill two V blocks and set them in a vise. see if they hold up cutting hardened steel, but hhs isn't much harder than high carbon steel.

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                  • #10
                    Anyone who has used Leatherman to cut fishing hooks knows how this usually ends up
                    Cutting edges usually deform and the jaws start to bind. For some reason similar cutter on Victorinox Swiss tool works without any problems with the same hooks that ruin the Leatherman immediately.

                    Some gerber models actually use carbide inserts in shear/scrissor style tool:
                    http://www.multitool.org/tools/gerbe...-legend-review

                    Carbide jaws are seen in some high end side cutters and bolt cutters.
                    For small precision work carbide tipped Erem's would be really nice but they are bit pricey:
                    https://www.amazon.com/595T-Diagonal.../dp/B000B600VC
                    Location: Helsinki, Finland, Europe

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                    • #11
                      Originally posted by MattiJ View Post
                      Anyone who has used Leatherman to cut fishing hooks knows how this usually ends up
                      Cutting edges usually deform and the jaws start to bind. For some reason similar cutter on Victorinox Swiss tool works without any problems with the same hooks that ruin the Leatherman immediately.

                      Some gerber models actually use carbide inserts in shear/scrissor style tool:
                      http://www.multitool.org/tools/gerbe...-legend-review

                      Carbide jaws are seen in some high end side cutters and bolt cutters.
                      For small precision work carbide tipped Erem's would be really nice but they are bit pricey:
                      https://www.amazon.com/595T-Diagonal.../dp/B000B600VC

                      Have you tried the new Leatherman with the replacable cutting edges? Mine have held up well.
                      Location: The Black Forest in Germany

                      How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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                      • #12
                        I use the Starrett wire cutters in both 5-1/2" and 7". They are great for cutting springs and piano wire.

                        https://www.ebay.com/itm/Vintage-Sta...AAAOSw2JxbotyG
                        Kansas City area

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                        • #13
                          Just buy a pair of hard wire cutters?, ok maybe not, however the bahco pair of them I bought is quite good, wedge not bypass though, the only bypass I’ve ever used or worked on was a pin cutting machine, the jaws we tungsten carbide tubes that oscillated, the wire was threaded through one the the other, length was set with a shuttle grip and away she went, the bin would fill with pins off a roll in about an hour, good thing was it straightened the wire as well as cleanly sheared it, the pins still had to be tumbled with abrasive to round the ends, it was surgical stainless hard drawn wire for combs.
                          I see no reason why the same could not be used in a hand tool, possibly thread the wire through the hole in inserts then slide the inserts to shear? We made our own dies from carbide 8mm rod, edm a wire clearance hole then Lap the sliding surface.
                          Mark

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                          • #14
                            Originally posted by Black Forest View Post
                            Have you tried the new Leatherman with the replacable cutting edges? Mine have held up well.
                            I saw those and was thinking of ordering the jaws and messing around with them. How heavy a wire have you cut? I messed up my regular leatherman cutters not long ago cutting off a store security tag I did not suspect was hardened! Took a bit of work with a diamond file to set it right.
                            Location: Jersey City NJ USA

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                            • #15
                              These guys eat hard wire very well. The diag cutters have one beveled cutting edge VS the other type with the opposing Vs. Dunno if that matters. JR

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