: Rob, This is just a guess here but the 1/2" shank bits are most likely
: bought by people who have a 3HP router with half inch collet mounted in a
: router table. A router that size is almost a necessity for working with
: large bits like panel raisers. By the way Grizzly offers either size
: collet for the same money--$19.95 per bit. Tom

One of the routers I use is a 3HP with a 1/2" collet. I have a collet reducer to use 1/4" shanks in this router. These 1/2" to 1/4" reducers are cheap and universal.

Rob