Taper Spin in Tailstock by Drill Chuck

  1. Gary Hensley
    Gary Hensley
    Yesterday I was drilling a 5/16" hole with the tailstock drill chuck in Sassafras and it started spinning. I removed pressure and backed off with the tailstock immediately and checked the taper for problems. The drill chuck male taper does have some fine marks showing where it spun in the tailstock.

    I always back the drill bit out after every inch or two of depth when drilling to allow the accumulated sawdust to empty out. In this case, there may have been something in the female part of the tailstock since I was changing drill chuck to live center on a frequent basis.

    My question is how do I fix this? The female tailstock taper is much harder to examine, but I plan to use a taper cleaning tool with alcohol today. I am also tempted to use some 400 - 600 grit on the male drill chuck taper to clean it up, since it is possibly trash anyway. Any help or advice will be appreciated.
  2. Walter Mooney
    Walter Mooney
    Hi Gary!

    I extend my quill at least 1-1/2" or more after ejecting my live center, before inserting my drill chuck. Then I 'pop' the dc in fairly forcibly. I've found this helps hold it in there pretty securely. I always hold the dc with my left hand while advancing or retracting the quill with my right.

    I don't think I'd use sandpaper on the male taper, unless it was maybe 4000 grit or more, like a micromesh pad. And maybe do that with some dna to simultaneously clean it. You don't want to make any marks or 'grooves' on the taper, which might in turn scar the female taper if the male taper were to spin.

    Best set of luck to you.
  3. Gary Hensley
    Gary Hensley
    Thanks for your reply Walter, that makes perfect sense. After reading your post, I remember seeing the machinist at work slap Morse Tapered tools into place with medium-low force to be certain they seated. I was concerned that my tailstock taper might be damaged, so I carefully cleaned it today with alcohol. When I started drilling, I slowed the lathe down slower than yesterday to about 300 RPM's and backed the drill bit out after drilling every inch or less. It worked perfect today and did not slip once. The drill chuck taper was even noticeable harder to unseat when I changed to the live center.
  4. Roger Chandler
    Roger Chandler
    Gary, I think you probably solved your issue by cleaning the female taper, and I would also clean the male taper on the drill center. Putting it in the tailstock quill with a little pop to seat it well should not be a problem. If it ever gets stuck, then use a piece of board or wide skew chisel between the quill end and the drill center body to help it self eject when retracting the quill with the handwheel. It should pop right out.
  5. Gary Hensley
    Gary Hensley
    Okay Roger, thank you for the feedback. The spinning episode put the fear in me, I will do a better job of keeping both mating pieces clean and seating properly when changing tools. The board trick is good to know if needed. Thanks again Roger and Walter for your help.
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