Retempering HSS drill bits

Discussion in 'Shop Talk' started by moopups, Aug 11, 2004.

  1. moopups

    moopups In Remembrance

    Messages:
    7,102
    Joined:
    May 12, 2002
    Location:
    In beautiful downtown Sticks, near Belleview, Fl.
    Scored a coffee can full of assorted bits at a yard sale but they have a blue hue indicating they were over heated via abuse. Is there a way to retemper them? What color should the metal be before cooling? Got 44 of them for $12.00, 5/8ths and down.
     
  2. kaji1

    kaji1 Member

    Messages:
    13
    Joined:
    May 14, 2002
    My advice is cut the off at the discolored point and resharpen them.
    First they would have to be drawn abd then rehardened, a slow and long process done at controlled temps, and then you would have to contend with warpage. Not worth it.
     

  3. BrushBuster

    BrushBuster Well-Known Member

    Messages:
    118
    Joined:
    Mar 30, 2004
    Location:
    va
    never done a drill bit before, but if i was going to try. i would take 1of them and normalize it then heat to different stages and try and when i got to a suitable hardness versus brittleness. i would normalize the rest, sharpen then temper to the same color. probably a blue on the cutting end gradually getting softer up the shank. you'll probably have some scale to contend with but that may be easier than having to reshape a hardened cutting edge. warpage could be a problem but if just for normal holes and nothing that has to be exact, it might not be to bad.