I am looking to put together a rack and pinion machine and have been playing around HubbardCNC and McMaster. I can't seem to find a 15tooth drive pulley and 72tooth pulley with the same bore. Can an XL 15t pulley with a 1/4" bore be enlarged to the 3/8" size found on the 72t pulley? If not, what size combination is out there that I'm missing to not require any drilling?

Thanks and Merry Christmas!