Expanding Mandrel for turning large tubes

[Toolmaker51]

Ooops. Accidental double post. Hello 'Select All-Delete'!

As consolation, your fixture has a name; it's called a Spider. Related version commonly used outboard the spindle end, supporting small material.

[neilg4dbn]

That makes sense, it's sort of like an inside-out spider. Thanks very much. I wondered if there was a name similar to Cat's Head.
This is the three-screw spider I made to support mostly long hex bar through the headstock. It's got more holes now, so I can use four screws or three. Much easier to align round or square stock with four screws.



Now I need to bore a two-inch hole in the outside wall of the shop and fit a bearing and spider to it so I can turn REALLY long workpieces through the headstock without any danger of whip!