Cathy, Miriam,
Yes as far as I'm concerned "Tri-Flowing" is a word.
I just added it to my hard drive memory LOL.
When I cleaned this machine I did pull the hook and bobbin carrier out. I had to it was a mess. Almost as much old solidified oil as the 127. I did lube it as well. But I just had one of those ..... kinda - sorta - maybe memories. Somewhere I saw some rust and even though it was cleaned off it might be the cause "IF" it was in the bobbin hook areas. I'll double check it and do some more Tri-Flowing.
Joe