No announcement yet.

How do I mill down the end of a drill bit?

  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Peter S.

    I've never done this but it seems to me that most large diameter bits have a generous shank length so there should be enough there to grip it in the chuck near the end of the flutes and still have enough sticking out to cut down. Likely a better grip than the cup holder. But doesn't this assume you will have a lathe with a 3/4" or 1" spindle bore? Not very likely to be in the home shop.

    Another thought: I frequently have the same problem in my Unimat: 1/4" chuck but I need a larger drill or mill. I just mount them in the 3 jaw and let the chips fly. This works on the Unimat tailstock also (perhaps not on the Sherline though).

    I also recently purchased an inexpensive 1/2" drill chuck and bored out the original threads and retapped to 12mm x 1 for the Unimat spindle. Again, it works on the tailstock as well as the headstock. Should have done this 30 years ago. Main problem now is buying shorter length bits (7" max between centers and the vertical column is not that tall either). They come in handy on the full size mill-drill also when changing from 2.5" long edge finder to a large diameter drill. All in all, much better than reduced shank drills.

    Paul A.
    Paul A.
    SE Texas

    Make it fit.
    You can't win and there IS a penalty for trying!