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Long skinny threading

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  • Rich Carlstedt
    replied
    Your Approach doing it in the lathe is a good one , do not desert it
    The rod breaking in the middle tells me you have a bad die.
    Buy a good die , like a OSG
    Make sure it has a adjusting screw to set thread diameter and is a split die , and try it on a known bolt to compare diameter settings

    Then do this , using power feed ..
    Set the Lathe to the correct thread ( ie. 16 Pitch) but do not engage the half nuts !
    mount the die at the end of the jaws ( close to you ) and clamp it
    do your rod set up and feed it into the die . Once you have threaded maybe 1/2 inch , stop the lathe
    , now, engage the half nut (still power off) and loosen the jaws, and hold the handwheel to put drag on the the carriage.
    Now start and stop the lathe for say 2-3 revolutions. When it stops, the die will be in time with the threading setup.
    Now tighten the jaws ( the die should not be recessed about .200 to .400 in the jaws) on the die and turn on power ( Halfnut still engaged !)
    You will not power thread for your desired length . WHen you reach that length , stop , disengage Threading half nut and then reverse to clear the die fully.

    Two things, make sure you start the thread on the die with the die markings ( ie Mfg) facing you - Die front
    Two , you did not mention material for the rod , so I am assuming you just got 3/8" rod from a hardware store...that may be crap ??
    Get some 12L14 rod if you can amd maybe your old die will work with that ?

    Rich

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  • mickeyf
    replied
    I think I'd try to first single point partial threads, and then finish to size and proper form with the dies.
    This is what I was going to suggest, as two other people have. The idea being that if you take only light cuts rather than try to do the entire thread to full depth on the lathe, you can get away without using a steady rest. After you have any reasonable amount of thread cut at all, the die will follow that, and because the die does not have to remove so much material is is much easier to do manually.

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  • lynnl
    replied
    The wood is what the jaws are made of. He's talking about clamps such as these: https://www.google.com/search?client...d+screw+clamps

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  • elf
    replied
    Originally posted by lynnl View Post
    I don't think he's threading wood. He's threading metal to make wood hand screw clamps.

    I think I'd try to first single point partial threads, and then finish to size and proper form with the dies. Rig up some type of follower rest (wood or otherwise) and then thread between centers. That should hold it stiffly enough to permit threading, particularly for light passes.
    He said he collected wood to make the clamps😀

    If metal, then single point the threads to about 75% depth, then use your dies.

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  • lynnl
    replied
    I don't think he's threading wood. He's threading metal to make wood hand screw clamps.

    I think I'd try to first single point partial threads, and then finish to size and proper form with the dies. Rig up some type of follower rest (wood or otherwise) and then thread between centers. That should hold it stiffly enough to permit threading, particularly for light passes.

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  • elf
    replied
    The Woodwright's shop TV show had a least one episode showing how to make an adjustable die for wood threads. You are making Acme or square threads aren't you?

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  • mattthemuppet
    replied
    This is a bit of a hack, but you could buy a length each of 3/8" all thread in left and right hand, turn the ends of one piece down to say 1/4" and drill/ ream the other out to a hair over that. The glue or pin the two together. Would take a lot less time than cutting the threads yourself

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  • Dan Krager
    started a topic Long skinny threading

    Long skinny threading

    I find this web site fascinating because there is so much to learn. I have a newbie question and if this has already been addressed somewhere on this site please steer me to it. The searches I could dream up were not fruitful.

    Being a woodworker with decent metal working capability, I collected some wood that I wish to make into 12" capacity hand screws; a bakers dozen of them. I have the jaws made and the short dowels that have cross threads, left and right hand. Now the challenge is to cut the threaded rods that pull the jaws together. Each 3/8"-16 x 18" long rod has 9" of left hand and 7 1/2" of right hand thread. Two are used for each hand screw and threaded through the dowel pins to pull the jaws together and apart. It has taken me nearly a week to use a hand die to cut all the threads on a pair of rods. Granted, I'm old, weak and can't pay attention to work steadily at it.

    One method I tried was to clamp the die in my 3 jaw lathe chuck and secure the rod on center using the tool post and by running the lathe as slowly as I could under power (not slow enough) feed the rod by feel through the turning die. Thought about using the thread gear but didn't. About half way through the 3/8" rod twisted off in spite of good lube and adequate feed. Just too much torque.

    At this point I'm out of ideas. Do not have a steady rest, so would have to make one if I try to cut this skinny rod with a single point cutter. Any suggestions? Thank you in advance. Meanwhile, back to reading all of the "Shop Made Tools"....

    Edit: the steady rest could be as simple as a block with a 3/8" hole in it traveling right next to the cutter. Might give that a go....
    DanK
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