Drilling deep in delrin - Page 2
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  1. #21
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    Quote Originally Posted by Ox View Post
    Just in case of grabbing in a quill app, just keep some tension of the quill brake.

    This is the "CNC" board tho.



    --------------------

    Think Snow Eh!
    Ox
    Hole that deep on a manual lathe with the tailstock will be a major PITA. Drill on the carriage. Parabolic drill to get chips out but grind the cutting edges flat. If not then it will pull for sure in one of two ways. First it may try to self feed and you will know when that happens. Second is that under very aggressive feeding the drill will pull a slight amount of material surrounding the drill tip into the flutes. This will result in an over size hole.
    I had this problem and it was a bugger to trace. Hole was oversize and roll tap was crap. Mazak SQT 250. I slowed the process down to watch and part came out perfect. Hmm, no problem. Full speed on next part and problem came back. Took a diamond hand file to flat the cutting edges and problem went away. That lathe does nothing but run acetal/delrin 4-6 hours every day.

  2. #22
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    Quote Originally Posted by Scruffy887 View Post
    Hole that deep on a manual lathe with the tailstock will be a major PITA. Drill on the carriage. Parabolic drill to get chips out but grind the cutting edges flat. If not then it will pull for sure in one of two ways. First it may try to self feed and you will know when that happens. Second is that under very aggressive feeding the drill will pull a slight amount of material surrounding the drill tip into the flutes. This will result in an over size hole.
    I had this problem and it was a bugger to trace. Hole was oversize and roll tap was crap. Mazak SQT 250. I slowed the process down to watch and part came out perfect. Hmm, no problem. Full speed on next part and problem came back. Took a diamond hand file to flat the cutting edges and problem went away. That lathe does nothing but run acetal/delrin 4-6 hours every day.

    So the suggestion here is go slower in Delrin®? And get a 7/8" parabolic Drill?

    R

  3. #23
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    We used to make a lot of Delrin cable junctions that involved drilling a 3/4" hole 7" into the part and then doing a finish boring operation. Peck drilled and used the coolant to blow the chips out of the flutes and never had a problem. Running a Delrin mill job and other than filling the dumpster with chips that we cannot sell, no problems with the deep drilling on it. It makes a mess but is easy on tools.

  4. #24
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    Quote Originally Posted by litlerob1 View Post
    So the suggestion here is go slower in Delrin®? And get a 7/8" parabolic Drill?

    R
    Zero rake and all should be fine. On the lathe I peck feed and need to pull out completely to clear chips. On the mill the peck distance is about same as drill D to start, dwell peck. I want the stringy chip to come out about 6" before dwell breaks it off. Spinning around fast enough to fling it off the table. That does not work so well on a lathe.


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