Repair a Singer-sewing-machine With Unsynchronus Needle

Your sweing machine is a very complex gadget to connect Clothes and Fabric together and make nice Applications on it.

Besinde a regular maintenance with cleaning from fuzz and oiling the moving parts it is essential to check the result of the seam and listen to the noises the machine makes during sewing.

If the seam is insufficient or the machine gets louder than normal you will get a hint to problems just comming up.

Most of the Problems a most likely trivial and well described at the maintenance-Book of the Machine. But there is one Problem, not described at the book but frequently appearing after sewing on heavy material like Jeans-Fabric, Sail-canvas or leather.

the machine gets out of Synchronisation and the Threads are no longer wound through each other to obtain a durable seam.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: What Happens With Thread During Sewing - Failure-analysis

A sewing Machine uses 2 threds which will be wound on each other with every stich of the needle through the fabric or clothes.

This process is made by quite complex mechanic inside the machine and therefore the two thread-systems has to be synchronized.

Normaly the upper thread is supported by the "Needle" through the clothes fabric down to the under-thread-coil. This is a system with a gripper, cyling arround the coil and winding the upper thread arround the under-thread.

Threrefore the gripper has to catch the string from the needle just at the moment, the needle returns upward.

If the needle is to early, the string will be tighten up before the gripper is able to react. If the needle is to late, the gripper passed over the thread-loop without a chance of gripping.

* You can see the result: there is no binding on the clothes and you can throw the upper-string directly from the fabric.

* You can hear a metallic click since the needle often pushes against the under-Gripper or parts of them. This click sometimes crescends to a rattle.

First aid to distinguish the error and reason of this.

* open the under-thread-system and observe the needle coming down - if the needle is just at the lowest point when the gripper appears above the loop, then the Machine is in sync and the reason is an other.

* For this it is most likely, that the needle is bent by accidental usage - replace needle and try again.

- If you see the needle comming down much before the gripper is next to it, or the needle just comes down, when the gripper passes, then the machine is out of Synchronisation.

- The loud rattling results in a conflict of the gripper-Wheel with the needle and may either bent the needle and after a while the needle will break.

It is verry important, to resync the sewing-machine as soon as possible.

Step 2: Open the Machine

If you had discovered the reason as an unsync Machine, the first step is turning off the machine and pull out the Main-connectors from the Line.

Then you are prepared to open the machine without danger to your life and without getting electric hazzards.

Remove the Needle-Plate as shown in this title-picture by loosing the screws with the red markers.

A Singer-Consumer Machine is well screwed and unfortunately you have to remove half of the housing at the front side.

As schown on the image at step 1 at the rear side of the Machine you will find 5 Screws.

* At the bottom edge of the main-part 2 , at the arm 1 and at the thread-holder an other 2

* the Spool-coil s rapper has to be removed (be aware of the metallic lid, layed in the housing frame - here you may improve the design by adding some glue or hot-glue, to fix this screwing-lid!

* the front covering of the Needle-holder has to be removed (1 screw at front, one behind-side)

* near the Needle-Mechanic a srew is now visible, wich holds the housing tight to the thread-path. loosen this screw by about 1 turn to the left. - so the screw remains at the rest of the housing and does not get lost.

* Last screws are found at the Main Foot: 2 Screws directed into the inner metal, 2 Screws fixing the Plasic housing from front-side to the back side.

Finaly pull off the knobs for the Needle-Position and Stitch-wideness and lay it appart to the rest of the screws into an extra box.

Now you are prepared to get off the front-Part of the housing.

therefore you have to know, that there are some plasic-lids along the edge to the rear part of the housing.

Press carefull at the edge and Pull the housing, most of the lids come offgrip without breaking and the housing comes off.

There are two other tricky position you have to know: At the thread-adjustment-wheel you have to bent carefully and lift the case above the wheel.

At the middle upper side of the Arm there is a plasic lid at the behind half of the case - just press the behind part carefully and rattle with the front part - so the Lid comes off and the housing gets out.

Step 3: Observe the Synchronization and Adjust

As shown in the scematic above, you will see the gipper at the left side - just passed the Needle. At this position you should find the needle half the way upward.

turn the Hand-wheel to get reverse to the position where the gripper is at the rear middle position (just behind the needle).

to change the synchronisation, you have to disconnect the motor-Axis from the under-thread-Axis.

For this reason the machine has a sleeve arround the axis acting as a kind of clutch but is operated by 2 screws to fix the position of the axis and to enable the movement being transferred from Motor to Mechanic.

Detailled Images will follow if requested to that ones I already posted.

Axis and "Clutch" is found at the main foot-Part next to the Motor. You will reach it from front and below side. Use a 3mm or 1/8' Hex-bolt to operate the inlayed Screws. Just loose the screws by a half turn leftward on the silver sleeve.

When the axis are turnable to each other - first push the axis of the thread-Mechanic (left part) tight into the bearing, so that there is no gap betwen the bearing-sleve ( black) and the bearing on the Machine.

then turn the needle slightly down to the lowest position and turn the axis with the gripper to position the gripper just a mm before the needle. Fasten all screws of the axis-system again and check operation of the gripper with thread.

if all appears well - continue with rebuild the housing.

################# FINAL Tasks ###########

Check if all has tightend in the proper way and the Screws on the plasic housing are not fixed to fast.

Replace the thread-coil into the under-Support and close the Needle-Plate.

Assemble the Power cord and starter ready to test with read fabric.

Adjust the thread-force to the new situation.

be pleased that you saved a Machine from scrap and your wallet from running empty.

all the best for your reparation trials.

Be the First to Share

    Recommendations

    • CNC Contest

      CNC Contest
    • Make it Move

      Make it Move
    • Teacher Contest

      Teacher Contest

    Discussions