Machine Maintenance - Should I time the machine?

[APQS]

The good news is that APQS machines are carefully set at the factory by skilled technicians; therefore, the timing rarely needs adjustment.

When it does, it's typically the result of something unusual happening, such as a cleaning rag getting swept into the hook assembly (hint: keep yours well away from the hook area when oiling it) or a severe needle jam. If neither of these disasters has happened to you and you still are wondering if the timing needs adjustment, here?s what to look for:

- Skipped stitches: ?On stitch-regulated machines, does it happen in stitch-regulated mode but not in manual mode? Check to see if there is a needle hole in the fabric where the skipped stitch occurred (by moving thread out of the way). If there is no needle hole in the fabric (it looks like a long stitch), your stitch regulator probably just needs adjustment. However, if it happens in both stitch regulated and manual mode, then the timing might need adjustment.

- The needle hits the bobbin: First make sure you have correctly inserted the needle with the scarf to the back of the machine and that the needle is inserted all the way into the needle bar shaft. Make sure the needle is not bent?try a new needle. Listen for clicking noises and check the bobbin edges for wear or burrs.

- Frequent needle breakages: If you are sure the needle is inserted correctly, and that other factors such as bulky seams or improper machine movement are not causing the breaks, and then re-timing may be necessary.

Re-Timing Your Machine:

Step 1: Set the needle depth.

This first step is critical to successfully setting the machine's timing. The needle must not be too high or too low. Remove the bobbin case. Put a new needle into the needle bar, and then lower the needle to its lowest position, using the hand wheel. Look from the front of the machine into the hook assembly. You should be able to see the entire needle eye. If you can, then move on to Step 2.

If you must adjust the needle bar, then use a long, straight tip screwdriver to loosen the needle bar clamping screw. The access hole for this is located directly above the fluorescent light on the front of the machine. (If you have a Millennium or Liberty, the front cover with the speed/stitch length gauge will have to be removed first to give you access to the hole.) Adjust the needle bar so that you can see the entire needle eye in the hook assembly, then re-tighten the screw (and replace the cover if needed.)

Step 2: Check for proper hook rotation.

With the needle bar in its lowest position, rotate the front hand wheel slowly in a clockwise direction (up on the left side, down on the right) while observing the scarf (that?s the notch in the back of the needle) and the point of the rotating hook assembly. As the needle begins its upstroke, the point of the hook should pass the needle slightly below the midpoint of the scarf. (Check your manual for a diagram of the scarf position.)

To adjust the rotation, you may advance or retreat the hook (rotate it left and right on the shaft) by loosening the three large set screws on the backside of the hook that secure it to the rotating shaft. Reposition the hook by twisting it on the shaft while holding the hand wheel (and thus the needle) stationary. Once the proper rotation is achieved, slightly tighten one of the set screws on the back of the hook. Wait to retighten all of the screws until after you?ve completed Step 3.

Step 3: Check for needle/hook clearance.

To assist you with this step, you should have a magnifying glass (we found a terrific 2 in. x 2 in. magnifier at Ace Hardware for around $7). Without a magnifying glass, you may think that your hook point is touching the needle when actually there is still space or "daylight" between them. If you can get a piece of paper between the point of the hook and the needle without force or flexing of the needle, you will still get skipped stitches. When the timing is properly set, you will see NO daylight when using the magnifying glass. In fact, the point of the hook has to just slightly move the needle and cross the needle just below half way on the scarf, as in Step 2.

To close the spacing between the hook and the needle, use a flat blade screwdriver to gently pry the hook forward (bringing it closer to the needle) WITHOUT changing the proper rotation you set in Step 2. If, however, the hook point is hitting the needle too hard (bending the needle), the hook needs to be slid backward (away from the needle) to the point where it just slightly deflects it.

Once this position is set (double check with your magnifying glass) and you're sure the rotation has not changed from Step 2, and then re-tighten the hook set screws. Turn each screw in a small bit at a time, so that each one is tightening its grip on the shaft equally. If you tighten one screw completely before moving on to the next, you risk throwing off all the work you've done by causing the hook to slide on the shaft.

Step 4: Adjust the hook retaining finger.

The hook retaining finger keeps the bobbin basket from rotating inside the hook. You can see it by looking down into the hook area from the top of the machine. It extends from the front of the machine toward the hook assembly. You'll notice a notched area on the bobbin basket (the part of the hook where the bobbin case rests).

The retaining finger must protrude into the notched area only far enough to keep the bobbin basket from spinning (about 1/3 of the way in). The thread passes between the finger and the bobbin basket?if it is in too far, the thread will get hung up and break. If adjustment is needed, loosen the single Phillips head screw holding the finger in place (under the throat plate area near the front of the machine) and slide the hook retaining finger to the proper position. Retighten the screw. Finally, make sure there are no burrs on the finger that may cut the thread!

Step 5: Perform a "dry run."

After you've completed all the adjustments, take the time to turn the fly wheel by hand to check your work. Make sure the needle doesn?t hit the hook, that the clearance is correct, and that the retaining finger is correctly positioned.

It's much wiser to find any misalignments now than to turn on the machine let it find the misalignments for you!

Timing can be intimidating at first...but we can walk you through it and you will be so glad you learned how to do it!

Dawn Cavanaugh

National Director of Education

APQS

1-800-426-7233

dawn@apqs.com