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    Default Hard threading

    Im looking for info/advice on hard threading. I have some parts that I'm going to have to hard thread out of powder metal, they will be around 50RC. the thread size is 3/8-24. Threading before hardening is not and option as we were given a written set of instructions on how to make the parts (they are for test samples). They will be done on an Okuma Genos L400 and are about 3 inches long when completed, threaded area is abou 5/8 long. Thanks

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    Don't use sharp Tools. Use a Threading insert with a corner radius. And don't use full form inserts either. But 50 isn't too bad at all.

    R

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    Keep the SFM down. Make sure you keep taking enough of a chip to keep the part from workhardening, but not so much that you chip the tool. There can be a fine line between hard/tough carbide grades in this application. I would personally lean toward tougher with lower SFM and a heavier chip load.
    Good Luck!

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    Sandvik make CBN threading inserts for hard threading, they work well as long you don't overload the point.

    266RG-16VM01A001EE 7015

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    The CBN might not be bad but I think you can get away with Carbide. Carmex makes laydown threading inserts with a HBA coating that is rated for up to 62 HRC. Here's the price I would charge on them. Part # 16 ER 24 UN runs $12.85 each comes in box of 5. PM me if interested.

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    Quote Originally Posted by Shop Supply Guru View Post
    The CBN might not be bad but I think you can get away with Carbide. Carmex makes laydown threading inserts with a HBA coating that is rated for up to 62 HRC. Here's the price I would charge on them. Part # 16 ER 24 UN runs $12.85 each comes in box of 5. PM me if interested.
    I haven't done a huge amount of powder metal turning, but I have done some.

    My experience with it has been that the hardness is only a part of the equation, while abrasiveness is a huge factor.

    A box of your Carmex inserts is cheaper than a single Sandvik CBN insert, but I'd still go with the CBN.

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    Quote Originally Posted by gregormarwick View Post
    I haven't done a huge amount of powder metal turning, but I have done some.

    My experience with it has been that the hardness is only a part of the equation, while abrasiveness is a huge factor.

    A box of your Carmex inserts is cheaper than a single Sandvik CBN insert, but I'd still go with the CBN.
    Did you try carbide first? What was your results? Like a part an edge type? Trouble holding size etc? i'm curious.

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    Quote Originally Posted by ChipSplitter View Post
    Keep the SFM down. Make sure you keep taking enough of a chip to keep the part from workhardening, but not so much that you chip the tool. There can be a fine line between hard/tough carbide grades in this application. I would personally lean toward tougher with lower SFM and a heavier chip load.
    Good Luck!
    Worrying about "work hardening" something that's already hardened is an unnecessary redundancy. (Waiting for the grammar police...)

    R

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    Hopefully this is an O.D. thread? You shouldn't have too much of an issue, like mentioned above, a corner radius helps.

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    Powdered metals do act different in regards to hardness, at least in theory. The idea being that the "overall" hardness of the parts may be 50HRC. But, the particles/carbides are much, much harder, thus the description that they're 'abrasive'.

    As a general rule, sometimes you can go with an alternating-flank infeed, to spread the wear along both edges of the insert. Personally, I'd try a hard carbide grade with a PVD coating first. (I don't even know if you can find CVD coated threading inserts ) If you can't get acceptable tool life, then CBN

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    Quote Originally Posted by Shop Supply Guru View Post
    Did you try carbide first? What was your results? Like a part an edge type? Trouble holding size etc? i'm curious.
    Main problem with carbide was rapid flank wear. CBN might not be always necessary, but it just makes the job go smoothly.

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