OH LORD, don't mention ADHD ....
I once took care of an 8 year old girl with that and she about killed me. I think she could out bounce, fidget, and squirm a Mexican jumping bean on steroids. Loved that little gal, and last I heard she's growing out of it a bit. But oh man what a hand full.
I think ...... oh wait, that gives me a headache ..... I once made a stitch chart on my #1 66 treadle ..... I'll go find it ..... don't go anywhere ......
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OK, I'm back, you still there?
With the knob all the way in I got 7 1/2 stitches per inch
One turn out was 8 1/2 SPI
Two turns out was 9 1/2 SPI
2 1/2 turns out was 11 SPI
3 turns out was 12 SPI
4 turns out was 15 SPI
5 turns out was 20 SPI
6 turns out was 28 SPI
7 turns out was 49 SPI
and at 7.5 turns out it quit feeding.
How that will equate to your machine I don't know. But it's something to check out.
Joe