I currently have 3 of these rotary machines. (Kenmore rotary machines were made by White).They are very sturdy and well built machines. Unlike any other vintage machine. One distinctive difference is that the rotary mechanism uses a friction drive wheel on the motor that contacts and spins the balance wheel “backwards”. I have heard it said that “White” is “Singer” spelled backwards.
Problem: While they are powerful piercing machines, I have noticed that starting the stitch would result in the friction wheel spinning against the balance wheel without the balance wheel turning. It seemed that after a little friction developed, it would begin to sew fine. New friction wheels must be different from originals because it was the same story for all 3.
I tried different things to overcome the slippage… tightening the pressure against the wheel and roughing up the drive wheel with sandpaper didn’t work. The solution was suprisingly simple…
Solution: A Bissell Style 7/9/10/12/14/16 rubber vacuum cleaner belt will stretch tightly over the balance wheel and provides plenty of friction for the friction wheel to spin. The difference is night and day and the power increase is amazing. 2 belts cost less than $5 bucks at Walmart.
Be sure to move the friction wheel away from the balance wheel when not in use. Otherwise, a dent will form in the friction wheel. It will still sew, but it is noticeable and I find it irritating. I use a pencil between the motor housing and the machine, anything that won’t scratch either will work as well.
Professionally Restored Vintage Fine Quality Sewing Machines 