Yeah, they probably have a tube it fits in, to be drilled, thru a hole in the tube or whatever it is, maybe a block with holes in it, thats all can figure. You ain't gunna do it on a drill press without a jig, thats for sure. Well the tracking was off just a hair, and 1 small piece of tape balanced the blades perfect. It's as good and smooth as it was when it was new !!! Yipeeeee !!!