Hi Rick
"My question is are all bushings the same size " Well yes and no, they should be same OD and ID most of the time but the threads are not always the same,they should be 20 threads per. inch but sometimes the pitch is not the same so to say the ring nut may not fit all the guides just right
here's just one spot to get them from..note they list the Skil router....
http://www.ptreeusa.com/routerAcc.htm#20262 http://www.harborfreight.com/cpi/cta...emnumber=95160
===========