My expereinces lead me to do the following : For modern-ish machines with standard fans, I replace the whole fan with the best one I can find. Alas most modern fans are not really worth repairing (even I say that :-)) For older machines, machines that I want to keep as original as possible, anything with odd fans, I try to rebuild them. Most fans will come apart. Peeling off the label often reveals either a cap over the bearings, or screws that hold the motor to the frame. After releasing that, you can see the end of the spindle. There's normally a circlip there, take that off, then slide the spindle out of the bearings and remove all the loose parts. Make sure you know where all the washers, etc go. If the beariongs are ball races, then either replace them (they are very likely to be a standard size) or try to remove the covers, wash out the old grease, and re-pack them with high melting point grease. If they're phosphor-broze bushes, you might just need to relubricate them, or you might have to make replacements. This is fairly easy on a small lathe. -tony