This is the one I made a few weeks ago. It tapers the rear 10" from 11/32" to 5/16". I haven't used plastic knocks in a while. I prefer self nocks. If you round all the corners and edges of the self nock they will not cut the bow string any more than any other nock. Anyway here is what I made from one 1"x4"x4' red oak board and six 1/4"carriage bolts, washers and wing nuts from Lowe's...
these are drain holes to get rid of the saw dust created by the tapering.
I used 120 grit belt sander belt I disassembled and cut to size. It is attached to the jig with double sided FG outdoor carpet tape from ACE hardware.
These are the spacers I use to adjust the taper. They are 3/8", 11/23" and 5/16" and are removable from where they are stored.
..note the "stop" I glued in at 10".
this is my first set of arrows to taper. They are 11/23 poplar with a 10" taper to 5/16" self nocks. They fly great.