On Mar 9, 3:47*am, wrote:
I was going to make a quick and dirty dividing head to use with my
Taig chucks on my X2 mill.

I thought I would basically run a shaft through a block of aluminum
with 3/4-16 thread on one end and a dividing plate on the other. Then
I thought: What shaft? What bearings?

Primary concerns here are not the rotation loads but absence of radial
and axial movement of the shaft.

I am not sure what engineering principles apply. Would an aluminum
shaft with a slip fit through a hole in the aluminum block suffice?
Presumably a steel shaft would wear out the aluminum. Would it be
better to use a steel shaft with bronze bushings? Ball-bearings seem a
bit of an overkill.

Maybe by the time I think this through I will find it expedient to get
a Taig headstock for $60+ and use it as a base for the project (a
common approach, apparently). However, I would still like to know what
is the correct approach if building from scratch.

Thanks,

Michael Koblic,
Campbell River, BC

I like these:
http://www.kalamazooind.com/products...exing-fixture/
I bought two used ones for ~$50 each and mounted one on an angle plate
with the axis vertical. If necessary the second can serve as a
tailstock to steady a long shaft, like the splined pulley broach I
have to make soon.

The Spin Indexer is less rigid but can be set to 1 degree with the
vernier holes on the top:
http://www.phase2plus.com/details.as...IN_INDEX&id=58

A chuck for them:
http://www.tools4cheap.net/proddetail.php?prod=5c3jaw

Then there's this:
http://www.harborfreight.com/3-inch-...kit-98077.html

The rotation load is VERY important when milling if the work diameter
is larger than the shaft clamp. You can arrange a clamp that secures
the work directly to the mill table at the cost of inconvenience.

jsw