Does the winder on your machine have a black rubber tire? I am used to model 66 with motor and lights, and the bobbin winder clicks down to the left of the chromed edge on the hand wheel. You might need to oil and clean quite a bit if joints and hinges are stuck, it should click in place and release with ease. Some treadles have the bobbin winder running on the treadle belt, if so you have bobbin winder with out a bobbin tire.
In theory you might have the wrong winder, but if your machine has had one owner, I guess it has original parts. Model 66 was made for 50 or 60 years, and went through many minor changes over the decades. Theres probably more than two types of winders for model 66. You might get more accurate help if you post a picture.
Last edited by Mickey2; 02-02-2020 at 11:08 AM.