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mjcodina

Help Pls: Cobra 4 Needle Not Picking Up Bobbin Thread

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Hi all,

I'm new to this forum and just got a Cobra 4. What a machine. I picked it up from the shop last week and have been using it a few days. I actually initially went on this forum to fix a previous problem so thank you very much for the help already

Anyways here's the problem and some questions:

https://www.youtube....player_embedded

I began having the thread jam yesterday while working on a messenger. I would get maybe 10 stitches into the thing and the thread would begin to twist a bit and kink and then a couple stitches later it would skip a stitch. I'd stop and fix it and then go on. The third time though it really jammed and I had to remove the shuttle hook and bobbin. I took out the jammed thread and put it all back together and now the problem is that the top thread won't hook the bobbin thread to take it up and out. I took a video of the thing and will post a link. After maybe 20 tries it finally hooked it but when I began stitching, the top thread wouldnt hook the bobbin thread and it only punched holes. So if you guys could help me out with this problem of it not picking up the bobbin thread and whatever is causing the thing to not stitch properly (the same problem I assume) I would greatly appreciate it. Couldnt get a word back from the Leather Machine today and ive got some projects I'd really love to be working on right now. Thanks so much.

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Here are some things to check and if necessary, change...

Remove the thread from the needle for now.

First, make sure that the jamming hasn't retarded the hook.

  1. Remove the throat plate. Rotate the wheel towards you until the needle reaches bottom dead center
  2. The hook should be slightly behind the needle at this point
  3. Rotate the wheel slowly until the needle raises about 1/8 to 3/16 inch above BDC, then stop
  4. The hook should be in the center of the cut-out scarf in the needle, about 1/8 inch above the eye.
  5. If the hook is still behind the needle after it has ascended 3/16" and if by the time the hook meets the needle, the eye is above the pickup point, the hook has been retarded by the jammed thread. There is an adjustment accessible from a steel disk covered hole in the base of the machine, on the lower front of the right side of the body. I have done this adjustment, but don't have my similar machine at home to guide you any further tonight.

It is also slightly possible that the needle bar has moved up from the shocks, placing the eye too high for the hook.

  1. Rotate the wheel until the needle and its securing screw are fully visible above the base of the machine
  2. Loosen the needle screw and lower the needle about 1/8 inch
  3. Tighten the needle screw to secure the lowered needle (don't lower the needle farther down than the screw!)
  4. Rotate the wheel and watch the position of the needle's eye in relation to the hook, as it ascends from BDC.
  5. If the lowered needle places the ascending needle's eye about 1/8 inch below the hook, that may be your problem.
  6. Thread the needle, hold the top thread up and rotate the wheel slowly, watching the formation of the loop as the hook approaches it. If the hook picks up the loop in forward and in reverse, at the stitch length setting you are accustomed to using, lock in this new position of the needle bar.

To reposition your needle bar.

  1. Remove top thread
  2. Unscrew two large screws holding face plate to end of body. One is on top-right, other is on bottom left corner. Carefully pull off the face plate and set it down.
  3. Locate the needle bar and identify the two screws that lock it into position on the crank that moves it up and down.
  4. Rotate the wheel to lower the needle until the tip just reaches the top of the feed dog.
  5. Loosen the needle set screw and move the needle back to the top of the mounting hole in the needle bar and lock it in.
  6. The tip should now be about 1/8 inch above the feed dog.
  7. Using the proper screw driver or Allen key, carefully loosen the two set screws that secure the needle bar to the crank arm in the head
  8. Lower the needle bar slowly until the tip of the needle is just level with the feed dog.
  9. Ensure that you haven't rotated the needle bar while lowering it and reposition it if necessary so the needle's eye faces sideways, with the needle set screw facing front.
  10. Tighten the two set screws as much as possible to lock the bar into this position.
  11. While the face plate is off, get a precision oiler and place a drop of oil into each oil hole on the crank arms inside the head.
  12. Reinstall the face plate, making sure you hook the tension release lever over the tension release stud that sits 2 inches under the top tension disks.
  13. Thread the top as per instructions that came with the machine.
  14. Make sure that the needle is installed with the scarf over the eye is facing due right.
  15. Rotate the wheel counterclockwise and see if the hook forms a decent loop and it gets picked up by the hook.
  16. Replace the throat plate and resume sewing.

To avoid jamming thread under the work, hold back both threads for a few stitches when you start sewing. If you can't hold both threads, at least hold the top thread steady, to keep it from getting drawn under the throat plate.

Edited by Wizcrafts

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mj, I would hasten to avoid trying to add anything to the inestimable Wiz' fine post, but in a very similar situation I recently managed to get my machine's timing out of whack by jamming my new Cobra 4 when the lower thread was jerked from my grasp at the start of stitching. Steve suggested an easy test to see if my bobbin was out of time with my needle. He told me to loosen the needle and reset it down about 1/16"-1/8". He explained that doing that, in effect advances the timing. If your machine then sews OK, you can either set your needles like that henceforth or adjust the timing. I chose to learn how to set the timing. It is explained in both Steve's video and in his instruction booklet. It isn't difficult, but it took me a few tries to get it right. Best advice, call Steve. He'll get you back up and running. BTW, as a new Cobra 4 owner, if you haven't seen Al Bane's instructional video, I'm sure you'll find it helpful. I know I have. I've viewed it many times and keep finding it helpful.

Edited by silverwingit

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