Check-Up For Smooth Sewing; Machine Working Heavily; Thread Breaks - White 671 Instruction Book

CHECK-UP FOR SMOOTH SEWING
MACI4INE WORKlN EAVlLY
If the machine works hard after standing idle for some time,
apply
a little kero
sene in place of oil. Then run the machine rapidly to clean the bearings, and
oil with sewing machine oil.
The use of inferior oil is usually the cause of the machine working heavily.
THREAD BREAKS
If the needle thread breaks, it is probably due to one of the following causes:
The machine being improperly threaded.
The tensions being too tight.
The needle being bent or having a blunt point.
The thread being too coarse for the size of the needle.
(see page 23)
The thread take-up spring broken.
If the lower thread breaks, adjust the bobbin tension (Fig. 18)
also see that the
inside of the bobbin case and the underneath part of the tension spring are free
from lint.
21