My 390E project has the earlier drum commutator. Does anyone supply the drum brush plate (left, below) as opposed to the flat face type (right, below)?

I'm looking at machining some bushings for the original, but any expert knowledge is appreciated.

390E brush plates

Firewood

 

"Nice try, Lao Che!"

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albertstrains posted:

Firewood

 what is the problem with the brush plate on the left? Are brush tubes worn?

Al

Everything seems OK except for the sloppy armature shaft hole. Thinking of machining bushings on my little Unimat and trying that. Got the motor running with new brushes and one home-made spring. Maybe the sheer sloppiness all round is an advantage .

Firewood

 

"Nice try, Lao Che!"

Firewood

  I believe that is a Bakelite material that the shaft goes thru

 You could try just resleeving it with small piece of brass tubing or a bronze oil lite bushing to fit the the shaft of the armature

 Fix the brass sleeve in place with metal epoxy? Might work

Al

  

 

If you go with a bushing, you need to be careful to get it centered in the original hole location. Otherwise the commutator will rub on one side of the armature and not spin freely. The shaft hole likely distorted in one direction, which means the center has moved.

George

George S posted:

If you go with a bushing, you need to be careful to get it centered in the original hole location. Otherwise the commutator will rub on one side of the armature and not spin freely. The shaft hole likely distorted in one direction, which means the center has moved.

George

Thanks George - for sure. I'm eyeballing a way to do an align-bore by mounting the motor assembly (minus armature) on my Unimat carriage. If I can get the height bang on, I should be pretty accurate with a bushing blank in place.

Firewood

 

"Nice try, Lao Che!"

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