Thursday, October 25, 2012

How to re-install the worm in a potted motor

If you haven't already, check out The Vintage Singer Sewing Machine Blog.  (  Rain has a very detailed tutorial on how to re-wire a potted motor.  I used it again this week as I was working the the Pittsburgh 201-2.

One thing that I do differently.  When I am putting the armature back in the motor and lining up the worm, I take out the screw in the end of the motor.

This allows me to place a small screw driver into the motor housing

I pull the screwdriver out far enough to allow the worm to fit in its home and then I slip the screw driver into the worm to hold it in place.

Then I slip the armature in and pull the screw driver back a bit to allow room for the shaft of the armature.  It works like a charm.  It is much easier than trying to hold the worm in place with a pair of tweeezers.  Once the armature is all lined up, I pull the driver out and replace the screw.

It is important to line the set screws up correctly when re-installing the worm.  I completely removed one of the set screws in the worm when I took the motor apart.  It just happened to be the one on the flat.  The flat on the armature shaft matches the flat on the armature. 
When you are reinstalling the worm, you can't see the flat.  But if you turn the armature and with your third eye, watch where the flat is in relation the to shaft, you can get a good idea where the flat should be. 

Easy Peasy.


  1. Thanks for the link to I needed the 'screwdriver 101' information! I can do just about anything cooking, but work on my Featherweight...not so much. I'm learning, though!!!