Messed up my machine (juki 441 clone), advice appreciated.

[Ysalex]

I have. After I originally did the timing just up through the hook timing step (stopping before this new step). After preforming this step, for reasons I will explain below, my hook timing was well off, and I wasn't getting any stitches. At this point I figured I would time it by eye, by threading the machine and watching the loop form and timing the hook myself. After I I did this my stitches were fine in forward, good tension as well, stitch in the middle of the leather, but I was getting dropped stitched in reverse. I Took a look while it was sewing and the hook timing was definitely off going in reverse.

I didn't, and still dont, understand the timing video, which is why I was going over it again.

You'll notice in the video, during the step that cowboybob was talking about for the hook timing, that he unscrews a bolt in the lower front window, locks the wheel with an eraser, then positions the hook. But then, because of where the bolt is in relation to the wheel, in order to re-tighten the bolt he has to move the wheel to make the bolt accessible. He takes out the eraser,  turns the wheel so that he has access to the bolt again. Doing this would ruin the relation he showed for where the hook should be vs. the angle he set the wheel too. He doesn't show how or why repositioning the bolt by turning the wheel works, since off camera away from view it's not turning the hook with it, so to me it seems like at this step either I am missing something, or he is totally getting the hook out of sync with where he orginally placed it on the wheel angle.

Anyways, thats why I was trying to follow the process all the way through, to hope to understand the timing better. Because I know this: If I position the hook the way its done in the video, my hook timing is well off. 

Edited August 3, 2020 by Ysalex
more info

[nylonRigging]

20 hours ago, Ysalex said:

Thanks guys!

 

i bought a couple types of extractors unfortunately none of them can get purchase, so all my efforts have come to moot.

 

and while the idea of removing the shaft has crossed my mind, it’s impractical. With the part that is stuck in place, I cannot remove the shaft either direction even if I managed to completely disassemble it. I’d have to cut the shaft off on both sides of the stuck part in order to remove it through the upper rear window, and I don’t have that inclination, time, or mechanical fortitude. 

 

out of curiosity, what do you guys think a machine in this condition is worth? I’m considering washing my hands and buying a new machine. 

 

You live over in Bend OR. , Don't know any sew Tech. there, but there is hand's-on Tech./repair in Salem, Portland, and across Br. in Vancouver . In the end it might have been the better choice for perfect timing job .

You can still take it to qualified people for a repair on the broken set-screw, and get it set-up/timed properly to the the requirements you want the machine to work at .

It 150+ miles from Bend to Salem and a Tech. there can drill that set-screw out, dissemble that part and re-Tap for using a little larger size set-screw . It a lot of driving for you, but you will end-up with the job being done correct.

.

.

Edited August 4, 2020 by nylonRigging

[Ysalex]

Update: i put the machine back together and I gave cowboybobs Timing method a try instead of the video. I am curious about one thing. My shuttle/hook has a bit of back/forth play, maybe 1-1.5mm. When I align the hook to the needle when the needle is at a 5.5mm rise, so I align it to the backward (counterclockwise) play, or the forward (clockwise) play? If the shuttle/hook should have no play, is there a screw somewhere I can tighten to stop it?
 

Either way, the timing is better. Its bulletproof in forward for sure. 
 

In reverse I still get missed stitches, although now sometimes I can string together 20-30 reverse stitches before a missed stitch. One missed stitch means they all miss after that point. Sometimes it’s only 3-4 reverse stitches before I start skipping, but it’s a definite improvement.

 

on the skipped reverse stitches, I have stopped the machine, opened the front cylinder arm cover, and taken a look at what’s happening.

 

The best I can tell, the thread develops a twist, sort of a counter twist. Like if you held a piece of thread between your thumb and index finger in both hands and twisted the thread in opposite directions until the thread opened up into its three different strands. When this happens the loop forming, the loop that the hook will grab, twists away from the path of the hook. the hook misses, and then I start to miss stitches. Sometimes it will catch 1 or 2 of the strands, which causes the thread to separate and rip on the bobbin shuttle.
 

I know nothing about these machines, but I have three theories that are all probably wrong:

1: Tension.

I have tried a lot of thread tension settings. Right now, using 207 nylon bonded thread, the thread is just loose enough on the bobbin and the main thread that I can pull the leather away from the machine with a mild pull. I get stitches in the middle, no knots or loops visible or happening on either side. that said, I don’t know how sensitive these machines are to tension. If the tension is bad, maybe it’s causing the thread to unravel on reverse stitches when the loop for the hook is being formed. 

 

2: The hook distance from the needle.

If I am not mistaken, there is an adjustment for how far the hook is from the needle. If my hook was closer, even when the thread twisted, the thread loop might still catch. The distance right now between the hook and needle is really small, but maybe this distance is very finicky.

 

3: The thread.

The thread I have is of an indeterminate age, since I got it with the machine. For sure it’s 1+ year old, but could and probably is a bit older. Does bonded nylon thread have a shelf life? Would old thread be causing that kind of issue?  I have also noticed quite a bit of either wax residue or thread fiber building up on the various loops and eyes along the thread channel, I’m not sure if this is an indication of anything.

 

 

 

Edited August 4, 2020 by Ysalex
More info

[RockyAussie]

28 minutes ago, Ysalex said:

Update: i put the machine back together and I gave cowboybobs Timing method a try instead of the video. I am curious about one thing. My shuttle/hook has a bit of back/forth play, maybe 1-1.5mm. When I align the hook to the needle when the needle is at a 5.5mm rise, so I align it to the backward (counterclockwise) play, or the forward (clockwise) play? If the shuttle/hook should have no play, is there a screw somewhere I can tighten to stop it?  ( THAT PLAY IS NORMAL AND I WOULD GO FOR THE BACKWARD COUNTER CLOCKWISE PLAY.)
 

Either way, the timing is better. Its bulletproof in forward for sure. 
 

In reverse I still get missed stitches, although now sometimes I can string together 20-30 reverse stitches before a missed stitch. One missed stitch means they all miss after that point. Sometimes it’s only 3-4 reverse stitches before I start skipping, but it’s a definite improvement.

 

on the skipped reverse stitches, I have stopped the machine, opened the front cylinder arm cover, and taken a look at what’s happening.

 

The best I can tell, the thread develops a twist, sort of a counter twist. Like if you held a piece of thread between your thumb and index finger in both hands and twisted the thread in opposite directions until the thread opened up into its three different strands. When this happens the loop forming, the loop that the hook will grab, twists away from the path of the hook. the hook misses, and then I start to miss stitches. Sometimes it will catch 1 or 2 of the strands, which causes the thread to separate and rip on the bobbin shuttle. (THIS COULD BE CAUSED BY QUITE A FEW THINGS SUCH AS THE LEATHER YOU ARE TRYING TO STITCH,THE NEEDLE TYPE, THE SETTING OF THE THREAD TENSION RELEASE SPRING, THE THREAD QUALITY AND PROBABLY SEVERAL OTHER THINGS).... WITH SOFT SPONGY LEATHERS NOT HAVING A LARGE ENOUGH CUTTING TYPE TIP THE THREAD LOOP CAN BE RESTRICTED AND NOT PULL UP, TO FORM THE LOOP AS IS NEEDED FOR THE HOOK TO CATCH IT. TRY A LARGER LEATHER POINT LR NEEDLE. MAKE SURE THAT THE THREAD TENSION RELEASE SPRING DOES START TO RELEASE UNTIL THE NEEDLE IS JUST TOUCHING THE LEATHER. TRY SOME OTHER THREAD. MAKE SURE THE SHUTTLE IS WELL OILED AND HARBOURS NO LINT OR THREADS THAT COULD INTERRUPT THE FREE FLOWING MOVEMENT.)
 

I know nothing about these machines, (ME TOO BUT DON'T TELL ANYONE) but I have three theories that are all probably wrong:

1: Tension.

I have tried a lot of thread tension settings. Right now, using 207 nylon bonded thread, the thread is just loose enough on the bobbin and the main thread that I can pull the leather away from the machine with a mild pull. I get stitches in the middle, no knots or loops visible or happening on either side. that said, I don’t know how sensitive these machines are to tension. If the tension is bad, maybe it’s causing the thread to unravel on reverse stitches when the loop for the hook is being formed. 

 

2: The hook distance from the needle. (YOU CAN GET VARIOUS THICKNESS SPACERS TO GET THE GAP SMALLER BUT KEEP IN MIND WHEN YOU ARE USING BIG NEEDLES AND THREAD IT MAY GET TOO CLOSE AND THEY ARE A PAIN TO GET IN AND OUT BETWEEN JOB . IF YOU REALLY WANT TO TRY IT ANYWAY YOU CAN CAREFULLY CUT ONE OUT OF AN ALUMINIUM COKE CAN AND USE IT. I HAVE. SHUSH. MAKE SURE YOU REMEMBER TO BACK OUT THE 2 SCREWS THAT HOLD THE SHUTTLE IN UNTIL YOU CAN JUST SEE THE SPRINGS.)

If I am not mistaken, there is an adjustment for how far the hook is from the needle. If my hook was closer, even when the thread twisted, the thread loop might still catch. The distance right now between the hook and needle is really small, but maybe this distance is very finicky.

 

3: The thread.

The thread I have is of an indeterminate age, since I got it with the machine. For sure it’s 1+ year old, but could and probably is a bit older. Does bonded nylon thread have a shelf life? Would old thread be causing that kind of issue?  I have also noticed quite a bit of either wax residue or thread fiber building up on the various loops and eyes along the thread channel, I’m not sure if this is an indication of anything. (COULD BE AND i WOULD SEE IF FRESHER THREAD STOPS THAT)

 

 

 

 

[CowboyBob]

7 hours ago, nylonRigging said:

You live over in Bend OR. , Don't know any sew Tech. there, but there is hand's-on Tech./repair in Salem, Portland, and across Br. in Vancouver . In the end it might have been the better choice for perfect timing job .

You can still take it to qualified people for a repair on the broken set-screw, and get it set-up/timed properly to the the requirements you want the machine to work at .

It 150+ miles from Bend to Salem and a Tech. there can drill that set-screw out, dissemble that part and re-Tap for using a little larger size set-screw . It a lot of driving for you, but you will end-up with the job being done correct.

.

.

This screw is still tight on the shaft & this adjustment does not need to be made.If it was my machine I would leave it alone.There is also 2 other larger screws that hold it tight to the shaft so it should never move.

Edited August 4, 2020 by CowboyBob

[CowboyBob]

3 hours ago, Ysalex said:

Update: i put the machine back together and I gave cowboybobs Timing method a try instead of the video. I am curious about one thing. My shuttle/hook has a bit of back/forth play, maybe 1-1.5mm. When I align the hook to the needle when the needle is at a 5.5mm rise, so I align it to the backward (counterclockwise) play, or the forward (clockwise) play? If the shuttle/hook should have no play, is there a screw somewhere I can tighten to stop it?
 

Either way, the timing is better. Its bulletproof in forward for sure. 
 

In reverse I still get missed stitches, although now sometimes I can string together 20-30 reverse stitches before a missed stitch. One missed stitch means they all miss after that point. Sometimes it’s only 3-4 reverse stitches before I start skipping, but it’s a definite improvement.

 

on the skipped reverse stitches, I have stopped the machine, opened the front cylinder arm cover, and taken a look at what’s happening.

 

The best I can tell, the thread develops a twist, sort of a counter twist. Like if you held a piece of thread between your thumb and index finger in both hands and twisted the thread in opposite directions until the thread opened up into its three different strands. When this happens the loop forming, the loop that the hook will grab, twists away from the path of the hook. the hook misses, and then I start to miss stitches. Sometimes it will catch 1 or 2 of the strands, which causes the thread to separate and rip on the bobbin shuttle.
 

I know nothing about these machines, but I have three theories that are all probably wrong:

1: Tension.

I have tried a lot of thread tension settings. Right now, using 207 nylon bonded thread, the thread is just loose enough on the bobbin and the main thread that I can pull the leather away from the machine with a mild pull. I get stitches in the middle, no knots or loops visible or happening on either side. that said, I don’t know how sensitive these machines are to tension. If the tension is bad, maybe it’s causing the thread to unravel on reverse stitches when the loop for the hook is being formed. 

 

2: The hook distance from the needle.

If I am not mistaken, there is an adjustment for how far the hook is from the needle. If my hook was closer, even when the thread twisted, the thread loop might still catch. The distance right now between the hook and needle is really small, but maybe this distance is very finicky.

 

3: The thread.

The thread I have is of an indeterminate age, since I got it with the machine. For sure it’s 1+ year old, but could and probably is a bit older. Does bonded nylon thread have a shelf life? Would old thread be causing that kind of issue?  I have also noticed quite a bit of either wax residue or thread fiber building up on the various loops and eyes along the thread channel, I’m not sure if this is an indication of anything.

 

 

 

Ok, put  your stitch length on zero so the feed dogs aren't moving & measure the distance from the needle plate opening to the feed dog on both the front & back they need to the same distance.Look @ the hook position on page #2.In this manual.Note to everyone NEVER USE CAM ON TOP FOR HOOK TIMING!

 

441 Engineers manual.pdf

Edited August 4, 2020 by CowboyBob

[Ysalex]

10 hours ago, CowboyBob said:

Ok, put  your stitch length on zero so the feed dogs aren't moving & measure the distance from the needle plate opening to the feed dog on both the front & back they need to the same distance.Look @ the hook position on page #2.In this manual.Note to everyone NEVER USE CAM ON TOP FOR HOOK TIMING!

 

441 Engineers manual.pdf

Thanks cowboyBob. 

I followed these instructions and yours for timing to a T, and now it fails to pick up any stitches in reverse or forward. The thread very reliably twists away from the hook.

[RockyAussie]

24 minutes ago, Ysalex said:

Thanks cowboyBob. 

I followed these instructions and yours for timing to a T, and now it fails to pick up any stitches in reverse or forward. The thread very reliably twists away from the hook.

A close up picture of the needle just entering the leather might help here. What type of needle is it and have you tried replacing the needle yet with a new one?

[Ysalex]

21 minutes ago, RockyAussie said:

A close up picture of the needle just entering the leather might help here. What type of needle is it and have you tried replacing the needle yet with a new one?

yeah, I've tried a couple different ones just to be sure. Thanks for your help BTW, its really appreciated.

[DonInReno]

....well, if you give up on it and want to go with a new machine let me know and we could come up with a price that works for us both.