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E3 dynamo bearings

Hi! How tight should the dynamo bearing at the drive end be on the armature shaft be? I have a new armature to which the bearing would need to be drifted on with heat applied.has anybody encountered this?
Many thanks...Andy

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Re: E3 dynamo bearings


I replaced the armature on my M20 E3HM dynamo some months ago and the new drive end bearing was a slight interference fit. I put the new armature in the freezer for an hour before fitting the new bearing. Slid right on with a little light oil. I do not recommend heating the bearing, as this can damage it if overdone, and is not needed if you freeze the armature to shrink the shaft diameter a little before assembly. If the bearing is an interference fit, use a drop of oil, and don't use thread lock fluid, it's not needed. If it is a slip fit at room temperature, then use a drop of thread lock when assembling to keep the inner bearing race from spinning on the shaft in operation.

Good luck.

Dave W.

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