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  • Dull broach

    Pardon me if this is (probably) one of those classic "dumb" questions but I have never heard this discussed before. I have the chance to pick up some DuMont keyway broachs very cheap (set 10-10A) but all 4 broaches are quite dull however they were correctly used and none have any visible chips. How practical is it to sharpen these things? As I said I have never even heard this discussed and I have no idea whether it is something that is commonly done or not. Any suggestions?

  • #2
    Surface grinder

    Its relatively easy if you have a surface grinder.

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    • #3
      No surface grinder, any other way that would be practical?

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      • #4
        any other way that would be practical?
        Send them to DuMont?


        Nick

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        • #5
          you need some way of moving an abrasive along or moving the broach along...surface grinder, T&CG are obvious. I suppose you could make a fixture with linear motion that held the stone....would be a bit of work but maybe it could universal enough to make it worthwhile, sort of poor mans tool grinder.

          If they'e cheap enough, pick them up and a way to sharpen will present itself; you get a grinder, a buddy gets a grinder, do it at highschool night class...maybe even in a sharpening shop would be reasonably priced.

          for dull used cutting tools though i'd think price would have to be very low, so low your worst case is they sit a drawer forever and you dont really care
          .

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          • #6
            If you intend to sharpen your broaches on your own, we suggest
            you send for our free fact sheet, entitled "Broach Sharpening".
            http://www.dumont.com/brosharp.html
            Last edited by Highpower; 07-09-2010, 11:54 PM.

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            • #7
              Correct me if im wrong.. but a brooch has nice straight teeth, with access to both sides.. no curves or anything.

              So whats wrong with sharpening it with a cheap diamond coated file or lap?

              Assuming theres no chips in the teeth, it should'nt take much more then a quick touch up. Sure, its gonna take a long ass time to sharpen em. So turn on the tv/radio, sit down with some newspaper or something to collect the dust, and get to it.
              Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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              • #8
                Broach Sharpening

                As long as the sides aren't worn or galled, they can be sharpened back like new.
                Where are you located? Maybe one of the HSM guys in your area could sharpen them for you for a nominal fee.

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                • #9
                  and if the tips are well rounded with bad sides, grind the sides to the next smaller size (or and "undersize" non-standard" or even "metric" broach").

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                  • #10
                    OK, I bought them for $75 so I guess I will find out if I can sharpen them or not. This set is on sale right now at Enco for $356 so I am thinking it might be worth it, if not at least I will have the bushings. I was thinking maybe I could use a Granite plate and some wet/dry sand paper with water, make up a jig to hold them straight run them over the paper on the Granite plate? I have sharpened planer blades this way with a home made jig and worked pretty good, still there is a lot of difference between a planer blade and a keyway broach. Worth a try I guess so thanks to everyone for your advice and I will give this a try and see what happens.

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                    • #11
                      make up a jig to hold them straight run them over the paper on the Granite plate?
                      A perfect way to finally ruin them!
                      They do have a relief angle. But with your way that angle will be negative, it will only rubb. You can resharpen it with a stone and a lot of dedication on the chest.

                      Nick

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                      • #12
                        Broaches are sharpened by grinding on the face. On a T&C grinder, a cup wheel is used at the proper angle. A fixture could be ginned up to stone the teeth manually.
                        Jim H.

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                        • #13
                          Originally posted by radkins
                          OK, I bought them for $75 so I guess I will find out if I can sharpen them or not. This set is on sale right now at Enco for $356 so I am thinking it might be worth it, if not at least I will have the bushings. I was thinking maybe I could use a Granite plate and some wet/dry sand paper with water, make up a jig to hold them straight run them over the paper on the Granite plate? I have sharpened planer blades this way with a home made jig and worked pretty good, still there is a lot of difference between a planer blade and a keyway broach. Worth a try I guess so thanks to everyone for your advice and I will give this a try and see what happens.
                          I think you're going to have to devise a way to sharpen each tooth individually, else as Nick describes you'll have no clearance.

                          I wonder if with a steady hand and a die grinder and fine stone they couldn't sharpened by taking some off the curved rake surface?
                          .

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                          • #14
                            Also many cutting teeth are stepped so as to take smaller cuts...sort of like a wood saw blade...ie right, left and a cleanup cut and then repeat


                            Walt
                            Walt

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                            • #15
                              Before you try and touch them up youself, it may be worth taking them to a precision grind shop/cutting tool sharpening service to get a quote.

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