Central Machinery Mini-Mill

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Central Machinery 44991 Manual Mini-Mill

This tool is no longer at ATXHS

This page is for historical purposes only. If you are interested in a replacement for it, bring the discussion up on the atxhs-discuss mailing list.


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Central Machinery 44991 Manual Mini-Mill
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Grizzly G8689 Manual Mini-Mill.jpg

This mini-mill is to be used primarily for metal or plastics. Special instructions are needed if using this mill on steel. Do not use on wood.

See also: Taig Mini-Mill

Requires Approval to Become Qualified for Operation

Contact Danny Miller, Joe Ngo, Robert Ristroph to get a walk through on the operation and safety for those tools. The owner is Riley Cassel and he is allowing us access to this tool. Jason Stewart has been maintaining it.

Installing Collets

Keyed spindle
Locking pin
  • R8 collets are located in the metal cabinet next to the mill.
  • Not all spindles are keyed, but ours is. Line up the collet keyway with the spindle key when inserting a new collet.
  • Insert the locking pin (aka. tommy bar) into a hole on the right side of the black housing around the spindle. Rotate the spindle by hand while gently pushing in the locking pin until it engages and locks the spindle. Now you can use a 17mm wrench to tighten and loosen the drawbar.
  • DO NOT LEAVE THE LOCKING PIN IN THE MILL. You'll break something if you try to start the mill while the locking pin is still engaged. A good habit is never taking your hand off of the pin while it's engaged, similar to never taking your hand off of a chuck key.
  • Don't hold the spindle nut with a spanner wrench when tightening or loosening the draw bar. The spindle nut is held in place with only a setscrew. It also preloads the spindle bearings, and if it were to move and tighten, then it could cause excessive wear on the bearings.


  • Switch between high and low gear only with the motor off.
  • Jiggle the spindle by hand when switching gears to make sure the gear teeth fully engage.

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