Singer 72W19 - Needle Vibration Adjustment; Adjusting Needle Vibration; Pitman Adjustment for Needle Position

17
NEEDLES—ADJUSTMENT OF BIGHT OR VIBRATION
See Figs. 2 and 3
The spreading and drawing in or vibratory action of the
needles is caused by needle vibrating cam and gear (e) driven by
driving gear (i), connected by lever connections (L) and levers
(J) to the needle holders (K).
On the outside vibration, the lever connections (L) draw
levers (J) toward each other and spread them on the inside
vibration, by their connection with needle holders (K).
On the descending inside vibration of the needles, their eyes
should be on a level with the material before they commence to
move
outward toward the hooks, which will bring the strain of
the expanding needles upon their shanks when they have reached
the lowest portion of the stroke of the needle bar.
To Change the Vibration of Either Needle. For a narrow
vibration adjust thumb nut (a) toward the center and for a wider
vibration adjust it from the center of the vibrator lever.
Should the points of the needles as they descend upon the
inside vibration appear outside of the grooves of the piercer, a
very fine
adjustment may be made by turning needle vibrating
lever
(J, see Figs. 17 and 18, screws Q) slightly to the left or right
to swing needle holder (K) in the direction required; thus keep
ing the needles properly housed during their descent.
As
the needle lever pitmans are independently mounted,
they must be separately adjusted.
Lengthening the lower pitman makes the inside needle
vibrate farther over the edge of the material, to the right, and
shortening the upper pitman makes the outside needle vibrate
farther over the edge of the material, to the left.
To obtain the best results and a uniform action of the needles,
great care must be taken to set thumb nut (a, see Fig. 2) of each
pitman an equal distance from the center of the needle vibrator
lever. Should the pitman require lengthening or shortening to
obtain a correct position of the needle, loosen screws (j) and move
the pitman to the desired position, then retighten the screws. If
these adjustments do not suffice, the time of cam and gear (e),
on the arm shaft may be changed by loosening the set screws in
pinion (i) and turning it slightly for an earlier or later vibration
of the needles.
From the library of: Superior Sewing Machine & Supply LLC