DeWalt ordinal sander is making a ringing noise when in use, any ideas?
Commenting years later since this is one of the top google results and I solved my similar issue.
Applies to a DWE6423 (Diagram Here)
I think it's a tolerance issue that allows the impeller (3) to hit the shroud (51). There were wear marks on mine showing this was happening, and the impeller rings like a bell. I think the recess for the bearing (52) is a couple mil too deep. Ideally you would have a shim for the outer race of the bearing in the shroud, but I didn't have anything the right size on hand. I pulled the bearing, and put it loosely in place allowing the bracket (53) to press it into position, but added some really thin washers between the bracket (53) and housing(51). That lifts the bracket a little and doesn't seat the bearing all the way in giving more clearance for the impeller. The washers I used were 0.030" (~0.8mm) which seems to work well so far. Theoretically the bearing could work its way deeper and end up with the same problem, but so far so good.
If I hear that again I'll look into ordering something like these washers (but cheaper, don't need to pay for mil-spec) as a more permanent fix.
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