How to use a die

Discussion in 'Horological Tools' started by Scottie-TX, Dec 8, 2013.

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  1. Scottie-TX

    Scottie-TX Registered User
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    Y'alls know by now I'm not the brightest bulb on the tree but I should be able to do this: Now, I've used taps many times but this is my first attempt to use a die. I've got a 6-32 die. I'm trying to thread brass, .138 dia. I applied some Hoppes oil to die and rod. All that's happening is it chews the end off the rod - no threads. It ain't s'posedta work thatta way. Whut'm I doin' wrong? It is a split die held only snugly to a die handle. I've tried using both sides of die.
     
  2. dAz57

    dAz57 Registered User

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    well if the rod is the correct size for the die and it is not biting in, try putting a taper on the end of the rod so the die can bite in.
     
  3. Allan Wolff

    Allan Wolff Moderator
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    Scottie,
    I will offer a few tips. Hopefully one will solve your problem.

    The die needs to be perpendicular to the part being threaded. If it is at an angle, the threads will be crooked and the nut will wobble. This may also keep the die from starting.

    Don't let the die wobble around, especially when starting the threads. This will cause a problem like you describe where it just chews up to end. To keep it from wobbling, both the part and die should be mechanically supported. Two options would be to put the work in the lathe headstock and hold the die with a holder in the tailstock. An alternative would be to hold the work in the chuck of a drill press and clamp the die to the table. Turn the drill press by hand.

    Apply pressure when starting the thread, like you are pushing the die onto the part. The smaller the threads, the less pressure needed. Push while turning until 2-3 threads begin to form. From that point the die should be able to pull itself along.

    Make sure to start the die from the correct side. The threads on one side will be sharp and the other side should taper from a partial thread to full thread. You want to insert the part on the tapered side so the die is not trying to take a full cut right away. Some taps say "Start from other side" on the non-tapered side.

    Use a good die. I once bought a cheap tap & die set. Taps weren't too bad but every single die would chew up the end and not make threads. I ended up replacing each die with a quality made one as I needed that size.

    Once you get the threads started, back the die off every turn or so to break off the chips.
    Hope this helps,
    Allan
     
  4. Scottie-TX

    Scottie-TX Registered User
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    Thanks DAZ, AW;
    DAZ I did put a light taper on end.
    AW, I pretty much followed your counsel with the exception of mechanically holding the die. I tried both holding the brass in the drill press and handholding brass in a hand drill while handholding the die handle. I believe this is a good quality die - about six bucks - looks precision. I have some Asian metrics really only worthy of chasing threads.
    SO; So I'm gathering there's a feel for this - a new skill to be learned. I'll try again. Thanks guys.
     
  5. Charles E. Davis

    Charles E. Davis Registered User
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    It might be the type of brass rod.
    It might be a left hand die.

    I would make my taper longer so it enters about half way into the die. Put the rod in a vise with the end sticking up. Using two hands on your die handle pretend you are using a post hole digger to get a big load of dirt to pull out.
    It should start to grab after a few turns. If it doesn't grab make your taper longer but don't reduce the end coming through the die.
    If it won't grab see if it will work on a piece of wood dowel. Or get another die.
    Ideally brass cuts by scraping and dies are generally made to be used on steel, but it is able to cut threads on brass so most of the time you never know the difference.
     
  6. Scottie-TX

    Scottie-TX Registered User
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    VOILA! Thanks CHARLES! Wish I had a Lamborghini or such to award the winner. You might be tied with GREGORY JOHN altho he provided the "inside" while YOU provided the "hands on". Now CHARLES, my first attempt was not pretty so I show my second. I've learned a LOT. 1. The taper was the key. 2. There is a "feel" similar to but not totally like tapping threads, and 3. Work dia. pretty critical. The first attempt was .138 and cutting was a tad more labored. Second run was .136. Progress smoother but threads a tad light - maybe not. The die stopped near the top and there I measured .140. It simply was NOT gonna cut two over.
    So: So I'm getting a feel for it and the parameters involved, thanx to you and GREGORY. Thanks y'all!
     

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  7. Scottie-TX

    Scottie-TX Registered User
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    #7 Scottie-TX, Dec 9, 2013
    Last edited: Dec 9, 2013
    Third time a charm, guys! Went back to .138 for a fuller dia. thread and this time I placed a piece of tubing on the die handle that would lock on the drill press post - the die and handle FLAT on the bed - brass in the chuck. I turned the chuck by hand with perhaps about five pounds of force on handle, lubing often with HOPPES #9 . When turning became tiring, I continued, using a small rod inserted into chuck key hole and proceeding a quarter turn at a time. Cutting was VERY smooth with no stalling, etc. and the result just textbook perfect.
    So what did I learn this time, ALLAN?
    Indeed it does need to be perpendicular and a SPECIAL thanks to you for that.
    So thanks again DAZ, ALLAN, AND CHARLES. I'm good ta go. Thanks to y'all I can DO this and I KNOW many others have been watching this with interest and benefited MUCHLY because they've experienced the VERY same problems when they tried and failed. Thanks again GUYS!
    Curvature in picture is due to poor optix. Workpiece is gunbarrel straight.
     

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  8. Grolb

    Grolb Registered User
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    Another suggestion: hold the workpiece in the lathe chuck and use a tailstock die holder. But don't try to cut under power, instead rotate the chuck by hand, using the chuck key for extra leverage if needed. You can cut the taper on the lathe first. Like using a tap, after cutting a few degrees you should turn the other way to break off the chips.

    Anthony
     

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