im building a typical grinder out of 2" square tubing commonly seen all over the web and this forum. i got my steel, started drilling holes and building the tracking mechanism. i bought a motor and plan on using pulleys(234). what length drive shaft should i be looking at. i plan on using 2 pillow blocks probably off of some extra square tubing i have. 5/8 bore i know, but the length i am not sure of. and is there anything else i am forgetting? do i need drive shaft keys? im new to all this. any help would be great. thanks