here is my jig for routing popper mouths,http://www.stripersonline.com/ubb547/image_uploads3/routerjig.jpg
basicaly the plug is center on the belly hole which sit on the 1/4 pin. the router is mounted on an x/y jig which allows fordifferant sized plugs.once set up you can fly thru mouths. i did blow a few apart, so wear safty goggles.

What is the red handle clamp thingy?

Striper knight, the toggle clamp holds the plug blank in the v groove ficture.

I never saw or heard of a toggle clamp. Nice jig.
Do you have a pic of a popper mouth done with
th router?