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Making little set screws or other small screws.

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  • Making little set screws or other small screws.

    I had to make an M2.5 set screw about 2mm long, when I was refurbishing a small crosslide for a jeweler's lathe. The old one was stuck and had to be drilled out. The tool and method may be interesting to anyone else doing that.

    I have pieces of angle iron that I can hold in a vise, with threaded holes for holding screws. This one has threaded holes in it from M1.6 to M3.

    So, I put an existing longer (salvaged) screw into the appropriate hole, from the bottom, sticking up off the surface. Then while holding that from turning, I filed the end flat, then used a small saw (X-Acto in this case) to put a slot across the end, keeping it in the middle.

    Once that was done, I took out the screw, put it in again from the top side, and screwed in as far as the length I needed, plus a bit. Holding the head with a screwdriver, I cut the screw. It was hardened, and I had to use a small triangular file from each side, then broke off the screw. The excess was filed flat, and the screw was backed out using the slot, so as to remove or flatten any burrs. The resulting screw went right into the hole it needed to go in.

    Here is a picture (not too great) of the angle plate for these metric screws. No big whoopee, just a piece of angle with tapped holes in it, each marked with size.

    Last edited by J Tiers; 01-23-2022, 02:17 AM.
    CNC machines only go through the motions

  • #2
    It may not be needed in this case, but set screws usually have a cup point to dig into the piece it will be stabilizing, or possibly a cone point or dog point.
    Paul , P S Technology, Inc. and MrTibbs
    USA Maryland 21030


    • #3
      Thanks for sharing. It seems I am always cutting a bolt or all thread off for some reason. I've used a nut in the past and while it works with a large nut, a small cheap nut gets crushed in the vice. I will put this on my list to make so I can quit one-offing it every time.
      Tom - Spotsylvania, VA


      • #4
        Great tip. Thanks!
        Paul A.
        SE Texas

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


        • #5
          Clearly time for prep of that jig is time well spent. It was a good description of the procedure too.

          While it's true that regular use set screws benefit from a cup or pointed tip normally there's been plenty of times I've made a special set screw or modified a stock one to remove the sharpness and either flatten or slightly round it so it won't burr the surface of the item being secured or won't dig into and spread out to bind a soft plug ahead of the set screw. And for this sort of use where it will bear against a shaft Jerry needs the same flat or smoothly domed end.

          Besides, when you're on the trail of a finished product who in blazes is going to wait for an order of set screws to arrive! ? ! ? ! ? !
          Chilliwack BC, Canada


          • #6
            Yes, since the end of the screw formed into a point or cup is intended to dig into a surface and prevent turning, it's not ideal for threads...... And I have a copper pad between the end and the threads, as in the original.

            So in this case, there is no need for a special tip, and it would actually be disadvantageous.

            If you DO need such a thing, and don't want to or cannot buy it, then you can do the same process as above, but then screw the thing into a hole in a piece of metal which allows enough material to stick out, so you can form the end in the lathe. A screw or plate behind the head of the setscrew will prevent it from backing away from the cutting tool while you work.

            Most such will need to be hardened, I would suppose, so hardening and drawing back would be the final steps..

            Some setscrews need to be quite short, making it hard to hold them, especially if they are threaded all along, leaving no head area to grip them by.

            The holder for such a screw to be finished in the lathe, could be a piece of round, that is drilled and threaded for the size screw needed at the end, slotted back of that to allow seeing the head of the screw being finished, and bored out and threaded with a larger size to pass the head and allow a (bigger) screw to be used to back up the setscrew against movement due to tool forces.
            Last edited by J Tiers; 01-23-2022, 09:06 PM.
            CNC machines only go through the motions