October 17, 2015

Ball Turner

I recently stumbled across a neat design for a ball turner on youtube, and ebay-rage-ordered all the parts to build one.

It consists of:

- A CXA (fits the MITERSlathe) boring bar holder with a 3/4" split bushing
- The cheapest 2" boring head I could find
- A 3/4" shank for the boring head

Total damage was ~$100.

I turned a couple 3/4" I.D. thrust bushings:

A handle:

The little radial-keyway allows the handle to be rotated 180 degrees and still have positive interference with the back of the boring head shank (which I filed a matching keyway into).

Threw together a quick carbide insert holder.  Someone else was on the mill, so all the shaping was done with a file, belt sander, and bench grinder:

Almost done.  The two set screws are used to tighten the play out of the split bushing:

To test it out, I turned a ball for the end of the handle.  Success!

The ball was tapped, threaded onto the end of the handle, and locked with some red loctite:

Not bad for an afternoon.


  1. how did you hold the ball to drill and tap it?? Cool build!

    1. I drilled the whole by flipping the whole piece around in the lathe before parting off the ball, and drilling through all the extra stock. To tap it, I held it in a vice with a v block, with some rubber sheet between the ball and the vice/block.