TIMING THE 111 W 155 MACHINE

Timing is the most important step when you are working on any machine. As you read through the following timing and adjustment sequence, you may find that it has changed from steps you are accustomed to using. This timing and adjustment section is presented as if you are taking your machine completely apart and reassembling it.

1. Timing the arm shaft with the hook drive shaft

To perform this timing step, you must tilt the sewing machine back on its hinges. Turn the balance wheel toward the operator until the thread take-up lever reaches its highest point. You can do this step by placing the fingers of your left hand on top of the thread take-up lever and turning the balance wheel with your right hand. You should be able to feel the high point of

Figure 4-3.-Side view of Model 225 sewing machine showing oiling points.

Figure 4-4.\Timing arrows.

the thread take-up lever with your fingers. You must check to ensure the arrows on the timing collar and the timing plate are aligned as shown in figure 4-4 (B) and (C). If the arrows don't match, remove the connection belt from the lower pulley (figure 4-4 [A] and [D]). Now turn the lower pulley by hand until the arrow on the timing collar (figure 4-4 [B]) is in direct line with the arrow on the timing plate (figure 4-4 [C]). Replace the connection belt. This completes this timing point.

2. Setting the feed dog height

Proper feed dog height is necessary to obtain proper feeding action. To set the feed dogs, proceed as follows:

a. Turn the balance wheel toward the operator until the feed dog reaches its highest point (figure 4-5), and observe the relationship of the feed dog and the throat plate. If the valley between the teeth is level with the top of the throat

^{Figure 4-5.\Feed dogs.}

plate, the feed dog height is correct; if the valley is not level,

b. Loosen the feed fork screw (figure 4-6 [E], table 4-1, foldout at the end of this chapter), push the feed bar (figure 4-6 [F]) up or down as necessary to obtain the proper feed dog height, and tighten the screw. This completes this timing point.

3. Centering the feeding action

To properly time this class of sewing machine, you must center the feeding action before the hook is timed.

NOTE: Ensure the needlebar rock frame hinge stud and the needlebar rock frame guide bracket are tight to prevent the needle from wandering from side to side or fore and aft.

a. Depress the plunger (figure 4-1 [H]), and turn the balance wheel toward the operator until the plunger drops; keep turning the balance wheel until it stops. This sets the maximum stitch length at 3 1/2 SPI.

b. Turn the balance wheel toward the operator and observe the movement of the feed dogs. If the feed dogs operate properly, consider them properly centered and continue to step 2. If the feed dogs strike the front or the back of the throat plate, proceed as follows:

(1) Loosen the feed-driving crank pinch screw (figure 4-6 [G]), and push the feed dog away from the point where it strikes; then retighten the feed-driving crank pinch screw.

(2) Turn the balance wheel toward the operator until the needle is at its lowest point and observe the relationship of the needle and the hole in the throat plate. If the needle is near the front of the hole but not touching it, proceed to step

4. If the needle needs to be centered, proceed to step 3.

(3) If the needle and throat hole are not properly aligned, loosen the needlebar rock frame rockshaft connection crank pinch screw (figure 4-7 [A], table 4-2, foldout at the end of this chapter) and align the needlebar in the hole of the throat plate; then retighten the screw.

(4) Turn the balance wheel toward the

operator and observe the operation of the alternating pressers. If the front foot does not strike the back foot, then the feeding action can be considered to be centered.

4. Timing the hook and the needlebar

In this timing sequence, we will consider that the machine has no timing marks on the needlebar.

a. Remove the throat plate, the feed dog, and the presser feet.

b. Turn the balance wheel toward the operator until the needle is raised three-sixteenths of an inch from its lowest point.

If the point of the hook is in line with the center of the needle, one-sixteenth of an inch above the eye of the needle, and as near to the needle as possible without touching it, then the hook and needlebar can be considered to be in time. If not, proceed to the following steps:

(1) Loosen the pinch screw (figure 4-7 [A]) and move the needlebar (figure 4-7 [B]) to obtain the proper height, as shown in figure 4-7 (C); then retighten the needlebar clamp pinch screw.

(2) Tilt the sewing machine back; loosen the hook saddle pinch screw (figure 4-6 [A]), the hook saddle adjusting screw (figure 4-6 [B]), and the hook drive gear setscrews and spline screws (figure 4-6 [C] and [D]).

(3) Move the hook saddle (figure 4-6 [U]) to the right and the hook drive gear to the left until they are disengaged.

(4) Turn the balance wheel toward the operator until the needle is raised three-sixteenths of an inch from its lowest point.

(5) With the point of the hook in the 7 o'clock position, engage the hook pinion gear and the hook drive gear to align the hook point with the needle. As you engage the hook, it will rotate clockwise, advancing toward the needle until the hook point is centered on the needle. The hook point should be as near as possible to the needle without touching it.

NOTE: The hook guard may be out of adjustment and prevent the hook from being adjusted close enough to the needle; if this is the case, bend the hook guard out of the way enough to allow proper adjustment. See step 8.

(6) Tighten the hook saddle pinch screw and the hook drive gear setscrews and spline screws.

(7) Turn the balance wheel toward the operator to ensure the hook does not strike the needle.

(8) The hook guard prevents the sewing hook from striking the needle. Adjust the hook guard (figure 4-8 [A]) by bending it until it is at least as near the needle as the hook point, but does not push the needle.

(9) Install the feed dog, the throat plate, and the presser feet.

NOTE: Ensure the bobbin-case lug (figure 4-9

[A]) is properly engaged in its opening in the bottom of the throat plate (figure 4-9 [B]).

5. Timing the presser-lifting eccentric

The presser-lifting eccentric controls the feeding motion provided by the alternating

Figure 4-8.\Sewing hook kit. ^pressers.

Figure 4-9.\Bobbin case area.

If the presser-lifting eccentric is not, properly timed, it can cause the machine to feed backward or prevent the machine from making the full stitch length.

The maximum stitch length of 3 1/2 SPI should beset while you are making the following adjustments:

a. Turn the balance wheel toward the operator and observe the action of the feed dogs and the front presser. They should meet at the

Figure 4-10A.\Presser-lifting eccentric connection link.

throat plate height and travel aft together; if they do not, continue to step b.

b. Turn the balance wheel and loosen the two set screws (figure 4-10B [C] and figure 4-10 [A]) on the presser-lifting eccentric.

c. Hold the eccentric to prevent it from turning; then turn the balance wheel a small amount toward the operator and tighten one of the setscrews.

d. Repeat steps b and c until the front foot meets the feed dog at the throat plate height as the balance wheel is turned toward the operator.

e. Ensure both setscrews are tight.