Hi Laurent, I struggled with this same problem week. Knocked my laminate trimmer off the bench, ruined the StewMac bit. I have a Frued 1" rabbeting bit laying around but the bearing shaft was too short for the SM bearings. Tracy provided a link for rabbeting bits that work with the LMI bearing set... maybe they'd work with the StewMac bearings if you used some kind of center bushing. Here's the thread:
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=18272As for me, I broke down and bought a replacement StewMac bit. A little pricey at $51 including shipping, but I've got 2 boxes that need binding, so I couldn't wait.