The arbor is likely to only be available from Powermatic, so I can't offer much help there, but the bearings should be available from a bearing distributor near you. If you can't find a bearing distributor, try an industrial supplier. Most big cities have both. The numbers that you will need should be etched on the bearings, usually on the side along with the manufacturers name. Something like Federal 7242 would have been made by Federal Bearing. Clean the bearings real well and then use a reflecting light to illuminate the sides of the bearing. An etched name and number or a symbol and a number should be there. If you can find it, then it will be easier to do your shopping by telephone. Take the old bearings with you to compare with what they offer. If they don't have an exact replacement they can usually find an identical replacement by another manufacturer. Many USA manufacturers are now out of business, so it's quite likely that your replacement will come from offshore under another name. They have cross references too, but again, a side by side comparison is the best way to be sure that your getting the right one. The price will likely be 1/3 - 1/2 of what Powermatic will want for them, if they have them.