SINGER W1240 - Manual (Page 5)

CHANGING THE NEEDLE
Flat side
Always make sure needle is straight.
To check straightness of needle, lay needle on a flat surface and see
that needle is straight and parallel as shown m above diagram.
Turn hand wheel toward you to raise needle bar to its highest posi-
Loosen needle clamp screw and insert needle upward as far as it will
go, making sure flat side of needle is towards back of machine as
shown in the above diagram.
Tighten needle clamp screw with screwdriver.
Follow the same procedure for insertion of twin needle.
To make sure that needle has been inserted
wheel toward you and see that needle comes down through the
center of the needle hole in the needle plate as shown in the above
Stiteh selector dial must be set in straight stitch needle position
when checking needle alignment.
If skipped stitches occur, needle may be incorrectly inserted.