Okay, after much looking and
lots & lots of researching, I think I may have figured out that it is
not the bobbin winder -- it is the belt guard. I looked at several parts lists that I have and found that the only difference was the belt guard. I went to look at the 66-1 with the spoke hand wheel and a later 1929 with an solid hand wheel with electric motor. Unfortunately, I misplaced the belt guard for the Scroll(red) 66. So I measured from the bend up over both belt guards and there is a one quarter inch difference. The electric belt guard is larger than the one for the spoked hand wheel. I then looked closer at the pictures you posted and it
appears to me that your belt guard was not the original one for that machine.
I found a couple of pictures that match one in my parts list. There actually looks to be a good blog about reassembling a 66 bobbin winder that has a picture of the correct belt guard a little over half way down the page.
http://errantpear.blogspot.com/2012/...in-winder.html There is also an ebay listing for a 66-1 red eye and if you look closely at the belt guard I think you will find it is different from yours.
https://www.ebay.com/itm/Antique-Sin...-/273938858540
Also looking at the image that you combined three images, it looks like your belt guard is higher than mine. I do have a partial picture of the belt guard that I took the good winder off.
So, maybe tape or smaller diameter wide rubber bands may be the way to go. I had a problem with one of my bobbin winders and even with a large bobbin winder tire, it was still a little off. I don't know where it came from, but I found a tubular o-ring, that I slit so that it would fit over the tire. It was just enough to get the winder to work.
Janey - Neat people never make the exciting discoveries I do.
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