I have had 3 of these Volstro units. Bought one for myself,one for my shop at Williamsburg,and 1 for my journeyman. mine is absolutely brand new,and the collets were still in their original boxes.
The first I bought had the spindle broken right off. I made a new one. It wasn't as complicated inside the unit as might be feared.
You should not use over a 3/8" end mill,or take off any kind of a heavy cut. That's how the spindle of my first was broken off. Also,the power feed with cogged belt that attaches to the Bridgeport's head,runs the unit around entirely too fast to be of any practical value. I don't see why Volstro ever came up with it. Just feed around by hand.
The unit is very handy for doing things that would be much more difficult with a rotary table. Just be sure to not overload the spindle. Should you break the fully hardened spindle off,it isn't too difficult to remove it and make a new one. I think the original spindle was too hard on my first unit,and I left the replacement soft. The original spindle had about a 3/8" hole bored up through its center. This was where they said they gripped the spindle to grind it. I left that hole entirely out of my copy,because I think it weakened the spindle too much,and had no use at all for sticking cutters up into.
Now that Volstro is gone,you can't get parts. The spindle used to be $119.00. I preferred to make my own.
Peter 
