1 ″x 8 tpi Bottle Stopper Mandrel - 3/8″ x 16 tpi threaded stud - Step Down is 13/16"
This 1" x 8 tpi threaded Bottle Stopper Mandrel threads onto the headstock / spindle and has a unique tapered-cut flute making it the best self-tapping mandrel on the market. It has a 3/8″ x 16 tpi threaded stud that works with just about all the stoppers on the market and numerous other projects: ice cream scoop handles, shaving brushes, pizza cutters, etc. They have a black oxide coating for rust prevention. The neck or step below the threaded stud is 13/16″ diameter which matches the tops of all Ruth Niles bottle stoppers (except Whiskey Stoppers. For those you will need a Niles Mandrel Adapter.. This mandrel does not use a draw bar. It comes with 2 nylon spacers (a spare because you will lose one!) which are used to help keep the wood from locking on the mandrel as you turn it. Use a 1 3/8″ wrench on the flats to start turning mandrel off the spindle.
*Tip: 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. Also try a little beeswax or soap on the mandrel before threading it into the wood.
The 5/16″ is the standard size when threading a 3/8″ hole; the 11/32″ is for dense wood, acrylic and resins.
The bottoming tap cuts threads all the way in unlike regular taps that leave about 1/4″ untapped and it makes threading quick and easy.