All;
Thanks for the great suggestions.
I had some tinker-time this morning.
oskar's idea of using sand paper and a drill worked pretty well.
I put a 60 grit sanding belt over a wood block, chucked a 2 prong corncob handle into my 3/8" VSR drill, rested the cork on a V-block and spun it down to size pdq. If I go into production a jig with 2 rollers on the bottom and a stop/rest for the sanding block on top would help. Centerless ground.
As for the punch, I was thinking like a carpenter, rip before you crosscut, there is no way a punch will work to cut a full length bottle cork down to size.
(maybe soaking the corks in Viagra would help?)
However when the corks are cut to length first, 3/8" to 1/2",I was able to use my honed 5/8" leather punch to cut them easily, that's how punches are supposed to work. It was a little awkward cutting the loose corks, it will be even more so with a larger punch of the correct size. If I pursue this method I think that gluing the blanks to a sheet of card stock would make for easier punching and provide a nitro card to boot.
Looking for cheap punches on the internet, found 18mm and 11/16" punches are too small and 19mm and 3/4" punches are too large. It should be easy to hone out a too small punch to the correct size.
Cobbhead;
Thanks for the offer, check your PM.
Thank you all for the great suggestions.
Bob 1900