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Tried to make a special size die.... a tale of learning through failure.

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  • #16
    You can single point any size of thread you like as long as the lathe can manage the thread pitch. Decent thread charts list the depth of thread per pitch and type, so you know how deep to go. I just cut a thread on a 1" UNF bolt shank, and fortunately checked the pitch first. I was expecting 12tpi, but it turned out to be 14tpi and on a genuine made in the USA bolt.
    Last edited by old mart; 03-12-2020, 03:44 PM.

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    • #17
      Originally posted by nickel-city-fab View Post
      I do wonder if that 7/64-48 die could be opened up to the 3/16 that you need, since they are 2-piece adjustable (look closely, those are Greenfields)... will have to experiment. If I can make it work, I'll make you a threaded rod, 3/16x48.
      I had to go back and look at the picture again. Yeah, that's pretty sweet that the dies are almost like little holders for the threaded inserts.

      Thanks for the offer but let me try the self made tap option first. I've made a few specialty taps over the years and they all went fine. And in truth I'm shifting gears a bit and now I feel that I'm better off to go with making a tap to make the die anyway. I'll do the three wire thing on the one good screw I've got to measure the tap I make. And that way I know that the die I make with the tap will be good.

      The big challenge is that this will be the finest thread I've ever done so I will need to take it in small steps.

      Old mart, yes I can cut the thread on each screw. But we're talking about literally 5 turns of thread at 48TPI up to a slightly larger point. And I'm looking at doing it a dozen or so times to make what I need for myself along with a few spares in case another one jumps ship in the future. So all in all it would be nice to just make a die and do a mini production run instead of single pointing each one.
      Chilliwack BC, Canada

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      • #18
        Originally posted by BCRider View Post

        Old mart, yes I can cut the thread on each screw. But we're talking about literally 5 turns of thread at 48TPI up to a slightly larger point. And I'm looking at doing it a dozen or so times to make what I need for myself along with a few spares in case another one jumps ship in the future. So all in all it would be nice to just make a die and do a mini production run instead of single pointing each one.
        Cool. If I had to single point that, I would just turn the chuck by hand. I'm really challenged by the smaller stuff.
        25 miles north of Buffalo NY, USA

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        • #19
          If you enjoy making odd threads, look into getting a Geometric Head.
          They have some really weird pitches available and what is neat is that all thread diameters are fully adjustable
          So a thread die of say 5-40 can be made to 4-40 or 6-40 in size as it is adjustable for Over/Under sizes
          Rich
          Green Bay, WI

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          • #20
            Originally posted by Rich Carlstedt View Post
            If you enjoy making odd threads, look into getting a Geometric Head.
            They have some really weird pitches available and what is neat is that all thread diameters are fully adjustable
            So a thread die of say 5-40 can be made to 4-40 or 6-40 in size as it is adjustable for Over/Under sizes
            Rich
            Yep, same idea as the Greenfield dies. A little micrometer screw moves the cutting edges in or out. That's one reason why I like them so much, you can "sneak up" on a close class of fit. The other advantage is that they can be re-sharpened easily with a slip stone.
            25 miles north of Buffalo NY, USA

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            • #21
              Originally posted by Rich Carlstedt View Post
              If you enjoy making odd threads, look into getting a Geometric Head.
              They have some really weird pitches available and what is neat is that all thread diameters are fully adjustable
              So a thread die of say 5-40 can be made to 4-40 or 6-40 in size as it is adjustable for Over/Under sizes
              Rich
              It's not that I enjoy it. Rather that some of the older firearms simply call for odd sizes. This need for what seems like it is 3/16-48 being one of them.

              I had a look at some listings for such heads found on Ebay. And I gotta say that it seems like a nice bit of kit. Looking on Ebay it seems like there's a couple of sizes available at a quick glance. I think I'd be looking for the smaller size for finer threads if this is the case. Something for the future... But for now I need 5 of the little devils shown below and two of a slightly longer size but same thread and diameters. So I'm going to keep going with the die making project.

              I actually did check with my local gunsmith and he was saying that Numrich is still not selling directly to Canadians. This really applies to barrels and receivers but US Customs is still seizing and laying charges over ANY firearm parts. Screws of this sort included. I'm not willing to take the chance since it would strongly affect my ability to travel to the US.

              My gunsmith buddy can and does order from Numrich on occasion. But there's a lot of added cost to process the export license and brokerage for such parts. If I did this myself my 7 screws would be well over $100 due to the cost of the parts, a miserable exchange rate at present plus the added cost of the export license and brokerage. Such is the cost of buying gun parts that need to be delivered out of the US at the moment. And while I could wait until he orders parts and group the order it would still be something around $10 to $15 PER SCREW.... And some many number of weeks until I get them since he only orders from Numrich about 3 or 4 times a year.

              Here's the little devil so you can see the size....

              Click image for larger version

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              Chilliwack BC, Canada

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              • #22
                Wow I didn't realize it was that bad lately. The US is a lot more paranoid than they were when I was a kid, we used to cross the border for a dime and party all night no questions asked. Of course that was 35 years ago.

                On the other hand, if you manage to figure this out, I can see how you could make a nice tidy profit on the side, by making oddball screws for the gun community in Canada!
                25 miles north of Buffalo NY, USA

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                • #23
                  You might have to single point that. There is no run-off on that thread visible, and a die will generally not thread right up to a shoulder, as appears to exist at the end of that thread.
                  CNC machines only go through the motions.

                  Ideas expressed may be mine, or from anyone else in the universe.
                  Not responsible for clerical errors. Or those made by lay people either.
                  Number formats and units may be chosen at random depending on what day it is.
                  I reserve the right to use a number system with any integer base without prior notice.
                  Generalizations are understood to be "often" true, but not true in every case.

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                  • #24
                    The way the screw seats it does not bear down on that shoulder. Instead the head comes to rest against a step in the ID of the steel bushing set into the wood of the pump action fore grip. It only screws in about 2.5 to 3 turns.

                    But it would have been a good call otherwise. And to be fair it sure LOOKS like it should bear down on the shoulder.

                    The small number of turns obviously puts a fair amount of stress on those few threads. Which would be why this is the better formed of the two screws I've got and the other from a different rifle has the crests of those last few threads that are used fairly badly worn.
                    Chilliwack BC, Canada

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