Shopsmith mandrel has a 3/8″ x 16 tpi threaded stud with a tapping flute in the threads making it self-tapping in most wood. The 13/16″ diameter collar is the same size as stopper top. Comes with free Allen wrench.
The nylon washer can be used as a spacer to help keep some wood from locking on too tight when you are turning your project. *note: if the wood does get a death grip and you can’t get the project off the mandrel, put the whole thing in the freezer for 10 – 15 minutes and it will unthread once the metal shrinks.