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Vintage Sewing Machine Repair Answered

I acquired a older sewing machine at a thrift shop, but it needs a little work. There appear to be two issues, possibly interrelated:

-The motor makes a strange intermittent screeching noise after the machine has spun up for a few seconds, and smells like ozone. I think the commutator is arcing. I'm not entirely sure though, I'm no expert on universal motors.

-The hand wheel sticks at one point during the revolution. This occurs when the needle, as well as the feed dogs, are fully up.

I'm guessing the sticking is demanding too much toque from the motor, causing the weird sound and smell. Regardless, de-gumming the thing and getting smooth motion seems to be the logical first step. I've applied mineral oil to all the moving parts I could find that looked like they would benefit from it. Now the motion is extra smooth, until it sticks, just as bad, and at exactly the same place.

I'm a bit stumped. Any ideas on what I should try next?


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7 months ago

Remove the cover from the machine, as well as the base of the machine. Buy some nice machine oil like Tri-Flow. Also, buy some Tri-Flow grease. Clean out the machine of any old gunky grease using q-tips. You can also clean the parts (but not the electrical parts) with rubbing alcohol. Make sure that you remove any lint and dirt you find. Slowly turn the handwheel and watch to see that all the parts are moving as they should. If anything is frozen (common after sitting for so long), spray Kroil or some type of creeping oil into the places where it's frozen and continue to work at freeing the parts. Old oil can glue parts together. You may have to let it soak and repeat applications. Some people swear by kerosene. Clean it out after you get everything moving freely again. Oil the machine thoroughly and apply fresh grease to the worm gears. Make sure that the bobbin case is removed and cleaned and that there is no lint or dirt built up. There are tons of videos on line that can help you decypher any other problems you may be having.