When the needle and shuttle are correctly timed, the point of the shuttle on its forward stroke must pass across the center of the diameter of the needle at a point one-sixteenth of an inch above the eye of the needle when the needle is on its upstroke.
To time the machine so the needle and shuttle operate properly, you must proceed as follows: Be sure that the needle is a class 16
Figure 4-14. - Rear view of oiling points on model 31-15 sewing machine.
Figure 4-15. - Bottom view of oiling points on model 31-15 sewing machine.Continue Reading