Never needed one until now. I see Kreg has a nice little jig that can be stacked for longer lengths. Also see one at Woodcraft by Wood River. That one can be used with either a special spring loaded drill bit or 1/4" router bit with 3/8" collar in a plunge router. I think the drill bit might tear out a bit more than the router bit. Any opinions on either, or any reasonably priced alternatives? Production speed is not really a factor for me, i usually just build a small number of cabinets and probably wont use it again for awhile. Im more interested in the accuracy of the holes so the shelves dont rock.