My sewing skills are fairly rudimentary. I'm including machine maintenance in that skill set. Some things are burned into my brain. How about replacing a needle and not knowing which direction to face the groove in the needle. It can be a mystery, if you don't have it written down in ink somewhere on the machine.
My sister quilts professionally, as you know, and can disassemble her machine in the dark, clean it and put it back together by the light of a flashlight held between her lips. She knows her stuff! On time I interrupted her to ask where the needle groove went on my Husqvarna machine. "The thread follows the groove!" she said, and left. I never forgot that.
Yesterday I found I no longer remember how many pieces must be disassembled to clean a machine! I was hemming towels, of course. Short of a modicum of mending, it's what I do on a sewing machine now. My current machine is a Brother, and it was jamming the thread. After I'd extracted the broken looper thread a dozen times, I thought I'd see if it needed cleaned.
The inside was brushed to shining, when I looked, and I could see nothing suspicious. In desperation, I began shoving my finger around the inside. Finally I decided it felt sort of soft, there under the throat plate. I located my screwdrivers and began. The screwdrivers provided by Brother are shite, by the way, but I got the job done.
Now I remember I used to do that job with a long screwdriver in a set of old Singer drawers that I no longer have. I wonder if I gave them to Janice. Must check and reclaim that screwdriver if possible.
Anyway, I freed the plate, turned it over, and smiled at the stuffed cushion it had become. What did I expect, shoving the needle through 100% cotton, the real deal, to hem towels? I cleaned and cleaned, replaced the plate and the screws, the latter with my thumbnails, and it sews like butter, to quote a malposition from my daughter.
Lint, but not in my machine.