Thanks for the information Janey!
To clear up misconceptions from my earlier post and photo, I include better photos of the bobbin winder and roller below:
As you can see in the left photo, the mechanism is adjusted as far as it can go. All photos are of the winder pushed down (engaged) and should be ready to wind onto a bobbin (not present) and still there is a gap of 0.2 inches from the hand wheel to the roller (right photo)! As far as my research goes, the roller diameter is correct (1 1/8 inches) and the hand wheel is correct. This really baffles me and I'm starting to wonder if this was an early model 66 that used the bobbin winder you mentioned (that rolls on the leather belt) and my grandmother got rid of that at some point, installed this one, and realized it didn't work and wrapped the hand wheel with tape to take up the gap. However I notice in many photos that Model 66 uses this style of Bobbin winder and it seems to work for everyone!!!
