Introduction
Issue: sewing machine bogs down every 8-15 stitches.
Replace the broken/worn out gear on the stitch cam shaft.
Tools
Parts
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Open the top of the machine to expose the internal mechanism.
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It is easier to replace the gear without the top cover in place. Loosen the screw holding the cover arm on. Remove the pin and set aside for later.
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Remove the two screws holding the hinges. Set the cover aside.
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Remove the three screws holding the assembly down. In my case one of the screws was stuck and I had to use locking pliers to loosen it.
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Push the needle position indicator to the side to access the screw beneath it.
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Pull the assembly to the left and up. It should come out easily.
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The shaft is held in by the set screws on the gear hubs: 1 on the cam gear, 2 on the little pinion gear 90 degrees apart. Loosen them 3 turns or so with a jewelers screwdriver.
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Slide the pinion gear to the end of the shaft. Gently slide the shaft back with needle nose pliers. Catch the gear before it falls.
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Push the shaft out the back then finish pulling it out.
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Loosen the two screws holding the gear and cam assembly together so that the screws can come out. Keep the screws in the holes to keep everything together.
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Push the gear shaft with fingers or screwdriver to slide it out. It may require the use of two screwdrivers to pry out.
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Insert the new gear shaft into the cam assembly. Line up the holes and thread the screws in.
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The new gear I bought came with an Allen head set screw so I swapped the old flat head setscrew into the new shaft.
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Set the gear and cam assembly in the sewing machine.
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Slide the shaft in, small end first, until it just protrudes from bearing on the gear side.
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Hold the pinion gear in place and slide the shaft the remainder of the way into it.
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Tighten the set screws on the gears (there are 2 on the pinion).
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Slide the needle indicator in from the left. Push the stitch selector aside as needed.
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Install the three screws in reverse order that you removed them.
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Turn the machine manually at least one full turn to make sure everything is properly in it's place.
5 comments
I need to replace the timing belt inside my Morse FA-630 machine. I'm still hunting down parts for this ancient machine, but I'm going to fix it myself. Do you have any pointers or concerns I need to be aware of?
Do you do repairs?
Do you do repairs? I have a Bernina 1230 I was told was toast but feel it is worth refurbishing
No, I'm just a mechanic that likes fixing things. If the dedicated repair shop says it's toast then I'd go with their opinion.