Tuesday, January 1, 2013

Knot Tonight (formerly No Knot this time)

 I finally did get the motor off of the 201-2 I am servicing.  It took PB blaster, time, Kroil, time, heat, Liquid wrench, PB blaster, Kroil, time, heat and finally some choice curse words but I got the screw loose.

It was cemented in place with old, dried, grease.  I think no one ever serviced this motor.  The grease wicks were as hard as rocks and the worm was pretty stuck to the shaft of the motor as well.

 The motor leads were safe but in a few years would not be. I decided to re-wire it.  I did the first one of these one year ago.  Since then I think I have done three others. Maybe four.  I have tied an underwriter's knot in at least two, maybe  three.  This time I soldered the leads in such a way that I just could not tie that knot.  I think it will be fine.  There really is no stress on the wires from the motor to the terminal block.  Next time I will solder closer to the coil and leave enough room to tie the knot.  Just cuz.
I was pretty pleased with how quickly I was able to do the soldering.  I used my little 25 Watt Weller soldering iron.  It heated up quickly and seemed to take less time to heat the wires than the Radio Shack 40 watter I had been using.  I had the whole thing done in 45 minutes.  Well, almost all done.  I had the terminal connectors to make but that went quickly as well.  Until I decided that I could do  a better job. Then I really mucked things up.   I trimmed the red lead too short and had to use a crimp on connector.  I was very conscious of not trimming the black motor lead (that connects to #2) too short and ended up not having quite enough bare wire to make a loop.  So I very carefully trimmed the insulation from the wire using my little snips.  I made a loop, soldered it just enough and WHEW all was fine.  I was RELIEVED.  Then when I re-mounted the motor, turns out there was some slack after all.  OH WELL.

When I put the hand wheel back on it was STIFF (TWSS).  I had cleaned the shaft and sanded it and cleaned it again and applied Tri-Flow.  Guess, not enough.   Off came that dang motor and I sanded the shaft and cleaned it some more.  Much better this time.

The machine sounds lovely.  The motor smells like a thunderstorm, though, and I think I will just get new brushes.  I cleaned the armature with electronic motor cleaner.  The brushes were a bit oily.  I soaked them in denatured alcohol and let them dry.  Still a bit of ozone smell.
The commutator was a huge mess, too.  Really gunked up.  There was actually a build up of crud along one edge.  Can't really see it in the photo.  Take my word for it.

Now to stitch test it and wire the foot controller and the power cord together.  It isn't a portable but it is so much easier to just plug the power and controller into the machine versus wiring the foot controller to the machine.  I gotta get back out there to play some more.  The shop is up to 70 degrees! That's what burning maple all day will do.  Toasty. 


  1. Nice post! I need to get braver about servicing motors. The more I do it, the better I will get, I know, but I'm always afraid of messing up something that wasn't messed up before I got to it! Laura

    1. I always recommend my friend Rain's blog http://vssmb.blogspot.com/2012/01/complete-how-to-re-wire-potted-motor.html for the best ever tutorial. It is all about potted motors. I think that's the only motor worth re-wiring. The Universal external motors are pretty inexpensive and easy to replace. Other motors, such as the internal motors in the 301, 401 Touch and Sew are not available after market, unfortunately.

  2. How did you sand the shaft? What caused it to need that?t is great to see you back in full throttle SM mode. Betty