Workholding on rotary table

Louis Ohland wrote in article ... I have adapted eight-inch, three- and four-jaw chucks to my rotary table.

It works for me. I bought a flat-back 4-jaw that was slightly larger than my table and turned a recess in the back that was a snug fit on the table OD. Drilled a couple of countersunk holes for SHCS to hold it down on the table using t-nuts in the table slots. Much improved the work holding.
Randy

You'll probably find that having a chuck on a rotary table will be very useful.
Many cheap import 4-jaws have counterbored holes for 10mm socket head cap screws, and they'll easily bolt to a flat surface. If the counterbores are oversized for the fasteners you want to use, you can turn (and drill) some reducer bushings for the holes to enable the use of smaller hardware. Hopefully, the RT will have four T-slots and not require a special spacer or bobbin-shaped adapter.
For quick centering, you might want to turn a center-registering "puck gizmo" that fits the center hole shoulder in the RT, and also fits the back hole in the chuck body.
WB ......... metalworking projects

If you do much rod work such as found on steam locomotives or connecting rods on any recip. engine, a small vise is very handy.
The vise is quite small, say 1.5" cpacity and jaw width x 1/2" jaw depth.
In use the vise is loosely clamped to the rotary table, the work centered on the table by means of a locating spigot in the table bore, and the vise tightened gently on the rod. Now clamp the vise securely to the table, and tighten the vise on the work.
The end of the rod is now completely free for endmill access.
Wolfgang