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MT3 Center Drill Holders

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Sunday, December 14, 2014 - 14:20

Not big on change overs/tool changes, if i can find a short cut, normally ill give it a shot,  so i made up six (really seven, but one came out alittle short) MT3 blanks which will find some kind of use down the road.

4# center drill is my go to for center drilling for tail-stock live center use so a dedicated holder seamed like a good idea.
Currently both of my drill chucks are 1/2", which is too small for the 5/8 shank on a 7# center drill so that will go in the shorter blank (not that i will use the 7# center too much, but while i was at it figured i would make a holder for it).

  • Popped a blank in the tail-stock and a center drill in the chuck.
  • Then drilled .010 under size
  • Finished with two reamers, "under/over" (4# center drill is .312 dia so first reamed with .311 and then finished with the .313 reamer)
  • Put a 1.5 MT3 socket in the milling vice, center drilled, drilled and tapped.
  • Ground a flat on the center drills for the set-screws to seat on.


End result:




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Looks good. I like the idea of making all the blanks at a single sittings. Thanks for the idea.

Joe's picture

Glad you like it.Not that setting up the tail-stock is a big deal, but once its set, it does make the rest of the blanks a 1-2-3 job even if you do not have any immediate plans for them.

Great! How did you get the blanks to be so shinny in the top right pic, next to your tool box ?

Joe's picture

Used emery paper; 220, 320 then stich brite (gray, thats what i had for woodworking). The finish from the tool was not too bad, did not have to do alot of work to get them smooth... They are not like ground and polished, but they are pretty good.

One thing I do for multiples is use a round faceplate with four ‘sides’ added to it to trap and center the rosette block. Then a center screw in from the back will hold the blank in place, and the sides keep it from spinning.

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