SINGER 12K Family - Manual (Page 6)

The preceding Instructions are full and complete for the'perfect
use of the Machine.
A few special notes are added below in explanation of any
adjustment that may be necessary.
THE SLACK THREAD PIN 'L^) presses down the check-lever (15).
It is adjusted properly for all classes of general sewing, and should never
be altered unless the thread breaks in sewing very thick cloth ; then loosen
the screw (14), and slightly lower the slack thread pin, after which retighten
the screw. Should it become displaced, it should be re-adjusted so that it
begins to press down the check lever when the needle-gauge mark is one-eighth
of an inch above the top of the arm.
THE CHECK SPRING (10) draws up the check lever (15). Should it
break or wear out, insert another as follow’s :—Move the needle bar (9) until
its check mark is level with the top of the arm. Remove the screw that holds
the spring, draw out the check lever half its length, holding it while putting
in the spring with its hooked end downwards, then move the check lever
back into its place. Replace the screw, turning it a few times only, press down
the end of the spring into the first hole (or into the second or third hole, if
using coarse thread), then tighten the screw.
THE PRESSURE SCREW (19) regulates the pressure upon the material.
Turn it to the left to increase the pressure, and to the right to decrease it.
Fabrics of thick or firm texture require more pressure than thin and soft
fabrics.
IF THE NEEDLE THREAD BREAKS when the needle is adjusted
properly, it is caused by the tension being too tight, the eye of the needle
being too small, the slack thread pin becoming displaced (sec Note above), a
roughness on the shuttle or its carrier, or by the point of the needle being bent.
IF THE SHUTTLE THREAD BREAKS, loosen the tension by passing
the thread through fewer holes. (See page 4, “ To Thread the Shuttle..’’)-
IF THERE ARE MISSED STITCHES, they are caused by the needle
being adjusted too high or too low, being bent away from the shuttle, being too
small for the thread, or by the point of the shuttle having become blunted.
IF THE NEEDI.E THREAD FORMS SMALL LOOPS on the top of
the fabric, it is caused by the check spring (HI) having become broken (see
Note above), and sometimes, when .sewing with coarse silk or linen thread,
by the needle being too fine or its point being bent.
IF THE STITCHES VARY IN LENGTH while hemming or sewing
very thick and soft fabrics, loosen the feed raising cam (62), and move it a
little to the left to raise the feed points, then tighten it firmly. Do not raise
the feed points too high ; when they descend in working they should be a little
below the surface of the throat plate.
SEAMS IN HARD COTTON FABRICS .should be passed over slowly,
and if these are e.xtra thick, rub them with a little white soap, which л\й11
facilitate the passage of the needle.
THE EXTRA THROAT PLATE, which has a large hole, is only
required when using a No. 21 needle with 40 to 60 linen thread ; never use it
for any other size. See page 12 for sizes of needles and threads.
THE LEATHER BELT must be tight enough to work the machine
without slipping. If it is too loose, cut about half an inch from one end, and
rejoin.