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I've bought a DIE without a tap...
- Thread starter vimes1984
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- Joined
- Dec 18, 2019
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- 6,428
What sort of thread is it? Is it 60 degrees, or more like trapezoidal with a flat top?
For folks with imperial lead screw lathes 4 TPI is relatively easy, my mini-lathe can cut it with "0" error. But I cannot cut 6mm pitch. Closest I can do is 6.032 mm pitch (0.54% error). You really need to measure the threads a little better. Can you cut 10 or more threads with the die and measure the total distance accurately? (Report the number of threads and the distance from crest to crest.) You will need a good quality scale or verniers. If the pitch is metric, all of the threads will line up very well on your (metric) scale.
If you can't do that, then I'd recommend finding a local machinist and ask them to measure the thread pitch accurately for you. Once you know the thread pitch, you can get a tap made. As others have mentioned, since you plan to cut wood with it, it does not have to be made out of high speed steel, nor hardened. Hardening wouldn't hurt, but could improve the tool life.
For folks with imperial lead screw lathes 4 TPI is relatively easy, my mini-lathe can cut it with "0" error. But I cannot cut 6mm pitch. Closest I can do is 6.032 mm pitch (0.54% error). You really need to measure the threads a little better. Can you cut 10 or more threads with the die and measure the total distance accurately? (Report the number of threads and the distance from crest to crest.) You will need a good quality scale or verniers. If the pitch is metric, all of the threads will line up very well on your (metric) scale.
If you can't do that, then I'd recommend finding a local machinist and ask them to measure the thread pitch accurately for you. Once you know the thread pitch, you can get a tap made. As others have mentioned, since you plan to cut wood with it, it does not have to be made out of high speed steel, nor hardened. Hardening wouldn't hurt, but could improve the tool life.
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- Joined
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Well, then the OP needs to find someone with a lathe that can cut metric threads with lower error than I can...
However, the intended use is wood, and we don't know how deep the threaded hole needs to be. Maybe the 0.54% error is ok. Probably need to account for moisture absorption for wood threads, so a somewhat sloppy fit is ok. Since we don't really know the exact application, it's hard to make more detailed recommendations. Just trying to help...
However, the intended use is wood, and we don't know how deep the threaded hole needs to be. Maybe the 0.54% error is ok. Probably need to account for moisture absorption for wood threads, so a somewhat sloppy fit is ok. Since we don't really know the exact application, it's hard to make more detailed recommendations. Just trying to help...
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- Feb 13, 2017
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Nothing really useful to add, just a similar experience with a couple of 1000 liter totes that I use for catching roof runoff, The tote was (probably) metric. It came from a Honda plant and had import stickers all over it. I started with a PVC pipe coupling from Home Depot. Everything was sized "more or less" and all done in plastic. The coupling was used rather than pipe because of the thicker tubing wall and easy to fit up a smaller pipe. I cut the threads to Imperial size, although I'm sure the male fitting was metric. Using rubber electrical tape, I made a sort of gasket and threaded then together. It doesn't leak in water usage, so is close enough to call it a fit. Some 3(+) inches in diameter, cutting the inside threads was easy enough.
On a philisophical note, I don't really use dies that often. Although I have many wood dies along with the metal working tools. The wood dies work on plastics like PVC quite effectively. When I acquire a "new to me" size tap, I order a matching die even though it seldom, if ever, gets used. Such things should always be kept in pairs. . . Like this situation, there is no telling what the future holds.
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On a philisophical note, I don't really use dies that often. Although I have many wood dies along with the metal working tools. The wood dies work on plastics like PVC quite effectively. When I acquire a "new to me" size tap, I order a matching die even though it seldom, if ever, gets used. Such things should always be kept in pairs. . . Like this situation, there is no telling what the future holds.
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