Rubber bobbin winder tire for most machines (15287A)
Fits many models, including, but not limited to:
Singer 66, singer 99, singer 15-90, singer 15-91, 15-88, 201k, 201-2,
401 (401A),singer 403, 403A, 99K,
319, 206, 306, 301, 301A
singer 127,singer 128, singer 27, 28 + more
.
Fits most Singer treadle and hand crank machines. 1-1/8" outside diameter. 29mm x 15mm
This small rubber wheel on the end of the bobbin winder spindle
The rubber wheel has to be in perfect condition and must be replaced if hard and cracked or spongy or loose on its rim.
We sell the Bobbin Winder Wheel for the 221.

Improperly loaded bobbins or bobbins that have the thread ‘tail’ caught around the outside of the bobbin or exposed can cause tension issues.
thread from the inside of the bobbin through a hole, then hold the thread tail close to the bobbin while winding so that it breaks off cleanly.
Old bobbins can have rust on them that will affect how they move within the bobbin case. Clean them with kerosene and emery paper if necessary.
Never use a bobbin that has been dropped on a hard surface or stepped on.