Pinion removal Humpback motor

Swede,

         I always use a Dremel  'cut off'  wheel to remove the gear. Cut just aside of the shaft, and it will 'pop off' w/o damage to the armature. A new replacement gear is available from us...$2.50 ea. It is not worth the time & cost to maybe damage the shaft if the armature is still good.   Harry

Harry, thank you very much for your response. 

The motor is a type 2 humpback. The brushes were run to destruction. There is some scarring to the commutator face and the armature wirings are blackened, possibly from heat. The pinion is in ok shape. Plate to plate and plate to post readings indicate the armature could still be ok. I planned to remove the armature to see if I could clean up the plate faces before putting together a "hope I can find" parts list.

I don't want to inflict any more damage to the armature than it has already seen so if I can't get the pinion off without destroying it, so be it. Very happy to know the pinion is available. Can you tell me if an armature and brush set can be found? The armature is SL-15, the brushes are 73-B and holders are 73-H.

Thank you again, swede

Yes, the hump back motor set is available as a complete brush holder set,...$16.00,  or copper arms & 'solderable  (silver solder)  brushes as a set.....$8.00  Harry 

If all you want to do is clean the commutator face and have a dremel i use dremels finest grit sandpaper a black emery disk but a used one not a new one, it will take the lines out and it will gleam like new.

Armature will spin freely when you touch it with dremel at a very slight angle but use a used finest black oxide type emery sanding disk not a new one,.

New brush assembly from Hennings is very good choice as well.

Harry and Dieseler, thank you for your information. I will be assembling a parts list as I go. As for using the Dremel, I had thought about that but am concerned that I cannot properly position the tool or maintain position to get a smooth even surface. I know I can do a better job with the armature out of the motor so will probably stick to that.

Thank you again, swede  

In my train repair and restoration projects I use the Dremel tool for many different things.  When I need a very accurate cut using a cut off wheel I put the cut off wheel on the end of the flexible shaft.  The diameter of the end of the shaft is much smaller than the tool  diameter and is much easier to control.  For instance in cutting track, you cannot get a vertical cut using the tool itself because the larger diameter of the tool forces the cutting wheel to cut at an angle but using the flex shaft you can get a neat vertical cut.

I have repaired many humpback motors for my collection of 150 series prewar electric locomotives and in several cases have removed the pinion gear using Harry's suggested method without a hitch.

Jim Lawson

Thank you for the response. I do not have a flex shaft for my Dremel tool but do think I can use it as presently configured to split the pinion like Harry suggested. A replacement pinion included with other parts I need is the least cost way to go. 

Thanks, swede