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Holding screws for modifying the ends.

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  • #46
    Now THAT is very slick idea! I think I like it better than my own option. I'm also thinking that if both the "collets" and face of the arbor were a little coned inward that it would aid with centering. But that's something I'd have to try.
    Chilliwack BC, Canada

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    • #47
      The matter seems to have been discussed at sufficient length by others but I have a note here.

      After an internet search, I came to the conclusion that the preferred spelling is "Higbee" end. At least, that spelling delivers a lot more hits in that search.

      An additional observation: if this style of thread end is machined on a thread in a lathe, it would seem that the remaining, full starting thread would begin with a sharp edge and gradually widen to the full thread width over the first thread. That would lead to a fragile thread which, if not modified, would also lead to problems with frequently assembled threads. I would think that some additional work would be needed to remove most of that initial thread or, at least to modify it's form. Doing an effective Higbee end is not just a simple lathe operation.

      Well, this video shows it being made on the lathe using a sudden retraction of the cutting tool at the end of the Higbee cut. An appropriate tool holder is needed for this.

      https://www.bing.com/videos/search?q...tail&FORM=VIRE
      Paul A.
      SE Texas

      Make it fit.
      You can't win and there IS a penalty for trying!

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      • #48
        Originally posted by Bob Engelhardt View Post

        Why doesn't the collet mar the threads?
        The grip force of the collet is spread out over the surface area on the major diameter of the threads.
        The pressure of this force is lower than the elastic limit of the material of the threads in compression.
        Asked and answered.

        -Doozer
        DZER

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        • #49
          That's right Paul. The final step for me is to dress away and ramp up the first thread with a small file. It's not as abrupt as the sudden retraction but it doesn't leave any sharp and fragile feathered edges either.
          Chilliwack BC, Canada

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          • #50
            So from just a hit on YT for random videos to consider one came up about shortening screws by YT member Mr Crispin. I thought about this long ago thread so I clicked on it to see what he came up with......

            I promise you on a stack of Machinist's Handbooks that I had no idea about this and did not even realize that he was a YT member. It's purely a case of parallel design.... But I did start laughing like a hyena when I saw the solution.

            I do think mine is a trifle better what with the threading die like drilled holes to encourage the "collet" to close better by flexing on the outer edge. But really, There apparently is such a thing as parallel evolution... 😁

            https://www.youtube.com/watch?v=AmS73LsDOmI
            Chilliwack BC, Canada

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            • #51
              For small screws up to 6mm you can use a pliers. The threads come out clean
               
              Helder Ferreira
              Setubal, Portugal

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              • #52
                Electricians pliers Needs superhuman strenght for 6mm normal 8.8 material screw. Soft brass or chinesium steel might be just doable.

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                • #53
                  Originally posted by MattiJ View Post
                  Electricians pliers Needs superhuman strenght for 6mm normal 8.8 material screw. Soft brass or chinesium steel might be just doable.
                  If you make a threaded plate with various diameter size screws that you can harden somewhat and then you can use a cold chisel to cut the screw. When you remove the the screw, it will clean the thread.
                  Helder Ferreira
                  Setubal, Portugal

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                  • #54
                    Noitoen, the original goal of the holders wasn't to simply cut the screws. It was to hold cut screws so the ends could be dressed up either to simply make them smooth and "nice" or to modify them with a Higby end as seen in post#1. If I were cutting them I'd just use a block with a hole in it and my bandsaw. It's a cleaner cut with less deforming. It's what I did with the screws after that which started this thread.

                    Chilliwack BC, Canada

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                    • #55
                      For cutting bolts to length, I just drill a cross hole in a piece of wood, then saw into the wood at the right spot for the required length. I hold the bolt in place with the driver and rotate it as I make the cut. The cut off end stays in the wood until the next bolt is inserted. I just finished doing about 30 odd bolts this way, threaded section needing to be 3/16 long. After the cutting the shorty bolts are put through a hole in some sheet scrap and held in place with a driver, and rotated while being touched to a sanding belt. There is a knack to getting the burrs sanded off cleanly, but it's not hard to learn.

                      I had to hold some bolts in the lathe a while ago so I could drill a hole down the length. For that I took a small piece of sheet copper, probably 30 thou thick, and wrapped it around the threads before chucking it. That protects the threads and the chuck jaws- but doesn't accommodate the head inside the jaws. For that I usually use my 3 piece adapter, which is pretty much the same thing you made- but I cut into 3 equal pieces instead of cutting one slit most of the way through. It's more of a hassle to hold the pieces onto the threads while inserting it in the jaws, but I think it centers the bolt better.

                      One thing I found with my project is that one of the bolts I was drilling had the head way off center. Didn't matter in this case because the hole was going down the center of the shank anyway. It looks funny because the hole exits the bolt nicely centered in the shank, but it's way off to one side where it goes through the head.

                      Something else I took advantage of when cutting off those 30 odd bolts- these were 8-32 and designed to hold knobs onto cupboard doors, etc. The Robertson headed bolts were a decent steel, but I found by accident that the Philips headed ones were much easier to cut. These are the ones that come pre-packaged with knobs and handles, and we usually just chuck those. But for this application I went and found enough of these Chineseum ones- and probably saved my band saw blade.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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