Brother 681B-UG - Manual (Page 35)

Oiling
For smooth and silent operation the moving parts of the machine should be oiled
periodically. (see diagram below)
OIL ONCE A WEEK IF MACHINE IS USED MORE THAN ONE HOUR.
PER DAY. IF MACHINE IS USED MORE OFTEN OIL EVERY DAY.
NOTE: If machine has not been used for along period of time, oil tends to coagulate and
operation of machine will not be smooth. To ensure best operation in such a case,
apply a small amount of benzine to oiling points as noted in diagram. For motor; One
or two drops of oil twice a year is recommended.
-33-