Drill Chuck Problem

Jim Krager

Member
Messages
267
Location
Salem, OR
Using a half inch drill chuck in my tailstock to drill out a hole in a vase I'm drilling using a 2 3/8" forstner bit the chuck keeps spinning off of the arbor. Does anyone have idea on how to stop this from happening?
 
Sounds like the torque generated from trying to remove so much wood at once is overcoming the friction fit of the Morse taper. Here's something to try:
  1. Drill to final depth with a regular twist bit (say, 1/4"). This will provide a center hole to (help) keep each successive step concentric.
  2. Back up to a (much) smaller-diameter Forstner bit and drill to NEARLY final depth.
  3. Use progressively large-diameter Forstner bits to remove more and more of the bulk, still drilling to NEARLY final depth.
  4. Drill to FINAL depth with the full-size Forstner bit. The idea is to remove the outer "score" lines created by the smaller bits.
 
What speed are you turning the vase at? Forstner bits, especially large diameter bits get really grabby if you try to turn at too high of a speed. I recommend 400 RPM or less if you can and feed slowly.
 
I found following Kerry's method best for me. Start small and work my way up. But, even doing that Steve's thought on going as slow as you can is quite good as well. Happy boring!!!
 
I may be misunderstanding your problem. It sounds like the chuck is unscrewing from the 1/2" threaded arbor of the MT.
In a drill there is a small screw inside which tightens to the chuck to the arbor of the drill, I do not know if the MT style arbor is tapped for a screw or not.
If this is the problem a small dab of the strong thread lock should fix it and keep it from unscrewing.
I think the red is the strongest (takes a torch to heat it up to remove it). Should be $5-6 at an auto parts store.
http://na.henkel-adhesives.com/industrial/red-threadlockers-permanent-high-strength-12892.htm
 
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