SINGER 404K - Manual (Page 30)

To Remove Gummed Oil.
If the machine should run hard after it has been idle for some time, this
is probably due to the oil in its bearings having become gummed. A little
paraffin should then be applied at each oiling point and the machine run
rapidly for a few minutes so as to dissolve the old oil, after which the machine
should be thoroughly wiped with a duster or a piece of waste material. Singer
Oil
should afterwards be applied to all working parts. Whenever paraffin
has been used, it is advisable to oil the machine a second time after a few
hours’ use.
If a machine should not run freely after treatment in this way, it should
be examined by a skilled sewing machine mechanic.
COMMON CAUSES OF MACHINE TROUBLES.
Causes of Upper Thread Breaking.
Machine incorrectly threaded. (See instruction book).
Tensions too tight. (See pages 18-19).
Needle bent or having blunt point.
Needle too fine for size of thread and material to be sewn. (See needle
table on page 11).
Burr on needle hole in throat plate (caused by needle striking the plate).
Burr on slot in presser foot (caused by sewing over pins or breaking
needle).
Needle incorrectly set. (See page 13).
Take-up spring bent or broken.
Tension discs worn so that thread works in a groove.
Causes of Lower Thread Breaking.
Tension too tight. (See pages 18-19).
Thread wound unevenly on bobbin or bobbin wound too full. (See
pages 8-10).
Spring on bobbin case or shuttle being worn.
To Avoid Breaking Needles.
Do not sew heavy seams with too fine a needle.
Use correct size of needle for thread and material to be sewn. (See
needle table on page 11).
See that the presser foot or attachments are securely fastened to the
presser bar and that the needle in its descent is central in the hole of the
attachment and throat plate.
Do not attempt to pull or remove the material until the needle is above
the work ; otherwise the needle may become bent and strike the throat plate
when re-starting to sew.
Do not use a needle of any other make. Use only Singer needles, which
are specially made for Singer Machines.
Do not leave pins in the material after basting.
Missing Stitches.
Needle not accurately set in the needle bar or being blunt or bent.
Needle too fine for thread used.
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