awhile ago clay asked about a jig to cut blockhead poppers.

well, river road creations has a set of jigs that could be adapted to do the job

if you are handy with power tools you could make a jig with a square hole or use the jig as is

http://www.riverroadcreations.com/im...rebsSetsSm.JPG

http://www.riverroadcreations.com/Ga...PopperJigs.htm