On Wed, 9 Mar 2011 04:59:33 -0800 (PST), Jim Wilkins
wrote:

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

I have looked at all of those at one time or another. I rejected the
spin indexer because of the 5C collets. The chuck adds $100 to the
cost. The rotary tables have the same problem.

Right now the job is to drill several cross holes in round stock at
precise but not necessarily outlandish angles. I was also trying to
use what was in the drawer. Maybe even learn how to thread on a lathe
:-)

I was going to buy the Grizzly rapid indexer but both Grizzly and Busy
Bee are out of stock. Also at 6" it would probably bee a tad too big
for my X2.

I suppose an option would be a spin indexer, a 3/4" collet holding a
short shaft with 3/4"-16 thread and a Taig chuck. Now that you made me
look at things again I should consider it.

Michael Koblic,
Campbell River, BC