The front bearing siezed on my Dremel 398. I googled replacing bearings, and came up with nothing really. Bearings appeared to be difficult to find, and no one appears to have stripped down and replaced them. Advice seemed to be, 'buy a new armature complete'! A new armature is available at 30 + vat + P&P. It appears that all Dremels are notorious for destroying the front bearings. One way to make money on spares then! A quick search on e-bay found this: http://cgi.ebay.co.uk/696-ZZ-QUALIT...2?pt=UK_BOI_Electrical_Components_Supplies_ET GAP Bearings are brilliant. Good value and ridiculously cheap P&P, even to Eire. Even better, Andy will help on other things that they don't stock. He has found me Bronze Bushes to re-furbish NWR's VWMS pedal box, and replicate a VWMS 020 Gear Linkage. Other suppliers did not even have the courtesy to respond to my e-mails! The biggest problem is removing the front part which hold the chuck jaws. I tried everything. Heating, twisting, etc. I made a jig to bash it off, but only ended up destroying the front bearing and closing it up to the end piece. I noticed that the armature winding assembly had slid along the shaft whilst bashing, so realised that I could move it a long way down to give shace to grip the shaft. First, I had to remove the rear bearing. I made space to do this by pushing the windings towards the front leaving space to rest the rear bearing on my bashing jig. A couple of taps using a pin punch and the bearing was off. Then I wrapped the armature in cloth and stuck it in the vice and knocked the shaft trough, using the pin punch, 'till I had space to grip the shaft. I held the shaft in the vice on the serrations as a little damage here would not matter. And warmed the front piece and twisted off with Mole Grips. I then tapped off what remained of the front bearing. I made a drift from a piece of tube to ensure that I only pushed on the inner race of the new bearings. So I pushed the armature windings back into place and fitted the bearings. NB: I measured everyting very accuratey before disassembly, and drew in all up on a daved type sketch. Now, re-fitting the front piece was a not so easy task. I heated it and tried dropping it on. It got about halfway before stopping. So, it was bash time. I assembled the chuck jaws and nut onto the front and tightened tham down so that I could bash away without damaging the end piece. I bashed a few times, with a nylon dead blow hammer, 'till it was in the right place. The armature had moved again so I had to push it back. 33000 RPM again!
Maximum respect on that! Normal people would throw it out and buy a new one, adding to more landfill, money spending etc. Thank god some of us aren't normal LOL.
