Shown pictured above with insert installed. Insert sold seperately.
The rotary adaptor threads onto the outboard spindle of the lathe and provides a place to attach the vacuum hose. It measures 5" by 2-1/2" in diameter. Using double ball bearings, the Rotary Adaptor keeps the hose from twisting with the rotation of the lathe. The vacuum is pulled through the hole in the headstock spindle (your lathe must have a hollow spindle with no cross holes). Your lathe must have an outboard spindle thread for the Rotary Adaptor to thread onto.
The Rotary Adaptor requires an insert which must be purchased separately. The inserts are the same inserts as the ones used for the Stronghold Chucks.