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New dies seem to be tearing the threads off

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  • New dies seem to be tearing the threads off

    I have a power threading machine 535 model. Recently I replaced the 1/2 - 3/4" dies and for some reason the new dies are tearing the threads when cutting. I've been thru every scenario, even bought another set. Same thing. All other sizes cut threads perfectly. Not sure what to do at this point

  • #2
    This happens from time to time with us and if you thread a lot of pipe on your 535 it will be sometimes easier to solve. Note the emphasis on easier. I'll assume your proficient and intimately familiar with threading on the 535 and in general. Sometimes despite all efforts it will require a complete rebuilding of the 535. For now do thus:

    1). Take apart the Diehead and thoroughly clean it and reassemble it. It's important the Allen bolts that hold the Diehead together be tight and remain tight thoughout the threading process. If these are loose your threads will be bad. I use lighter fluid for grills, cotton rags, bamboo skewers. MOST OF THE TIME IF YOU DO THIS YOUR GOOD TO GO.

    2). Use new and clean "Dark" oil. Grit, sand, water, tobacco spit, even metal fines will contribute to poor threads. Use the same as above to clean the oil sump.

    3). Grease the zerk fittings under the cover with lithium grease. Check your manual and follow directions on critical moving parts that also require lubrication. It's not enough that the 535 is oily by nature, correct lubrication is key.

    4). The oiler should be pumping at least a cup of oil in a minutes time. The sharp fines in the oil begin to chew up the seals on the pump and over times the flow of cutting oil diminishes which often leads to poor threads. Oilers rebuild kits are widely available for the 535 which takes about 20 minutes to do.

    5). Often overlooked it's critically important to make sure your pipe is of high quality. Some alloys are harder and more brittle, some are softer less brittle and more forgiving.

    Hopefully that's a good starting point and if you've already done all of it rent or buy a new Diehead and if that doesn't work rent a 535 and use it for the purpose of comparison. As I wrote earlier sometimes you just have to rebuild the entire machine. It just depends how much use the machine has under its belt. 535's are solid machines, money makers and will provide reliable service for decades with normal maintenance. We have some ancient 535's that look like hell but work like champs.
    Last edited by Mightyservant; 04-03-2019, 11:23 AM.


    • #3
      buy some pipe from other locations and try that. You could also take some of your pipe to the hardware store or supply house and let them give it a shot with threading it.

      You sure you have a matched set of dies in the proper order? Have you tried cutting threads not as deep and give it a second pass?

      phoebe it is