I need to create some 10mm dowles with longitudinal flutes so they can
be driven into holes with glue on wood joints ....
Length of dowels will be about 200 or so.

Bought the round 10mm stock ........ I have thought that I could put
flutes in using a small V cutter in a router ... 3 equally spaced flutes
about 2mm deep would be enough.

Anybody had to do this ... just looking for simple way to hold wood (or
router to accomplish.

I have a 1/4" hand router, also have a 1/2" router table.

At moment can't think how to stop wood rotating (or flying across room)
.. this is a one off job, so don't wnat to waste time & money on some
over the top jig.