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General Upholstery Questions and Comments => General Discussion => Topic started by: gene on October 20, 2011, 03:55:59 pm

Title: sewing machine problem
Post by: gene on October 20, 2011, 03:55:59 pm
Howdy.

Juki LU 562

The needle is cutting the top thread - cutting strands until the thread bunches up and breaks.

I found the needle bar had slipped down to where when the walking foot was up, to run the bobbin winder, the bottom of the needle bar was hitting the walking foot and being pushed to the left each time. I adjusted the needle bar. The thread cutting by the needle continues.

With the needle bar no longer touching the walking foot, by just the slightest amount, the looper will not pick up the top thread. I lowered the needle just a slight bit and the looper now picks up the top thread with no problem.

I am assuming that I should be able to have the needle all the way up and work just fine, but this is not the case.

Is it possible that the needle bar has been bent just enough to be causing this? I do not see any deflection or bending. The needle seems to be going perfectly straight up and down. Or is there some other adjustment that I need to make?

You can't put labor back on the shelf. (I love that line.) It may be cheaper to do maintenance yourself, but not by much. I spent a lot of time with this issue today.

Thank you for your thoughts and ideas.

gene
Title: Re: sewing machine problem
Post by: sofadoc on October 20, 2011, 04:14:22 pm
Sounds like your distance between the hook and needle may be off.
Title: Re: sewing machine problem
Post by: Mike8560 on October 21, 2011, 04:24:46 am
I don't know much on repair. If the thread s being hooked and now only the thread Is being cut try a new meddle maybe it got scared   
Title: Re: sewing machine problem
Post by: Toledo Mach. Sales on October 21, 2011, 04:56:40 am
My guess is the hook timing is off you need to abvance it alittle big moving the big gear underneath to the right maybe 1/8" then you can raise the needlebar back to where it belongs.
HTH,
Bob
Title: Re: sewing machine problem
Post by: BigJohn on October 21, 2011, 01:41:13 pm
Gene:
     Listen to Bob he knows what He's talking about, if any one can venture a guess without seeing it  and stand a good chance of being right it's Bob Kovar from Toledo Sewing Machine Company!
Title: Re: sewing machine problem
Post by: gene on October 21, 2011, 03:20:23 pm
Thank you for your replies. And congrats Big John on making Yabb God.

New needles were the first thing I tried.

I put the needle bar back where it belongs. I then adjusted the height of the presser foot so the needle bar would not hit it when the presser foot is in the up most position.

I then checked and rechecked the timing. The book that came with the machine is really good at showing what to do. I moved the big gear underneath and found where it worked best. It is now picking up the top thread with no problem.

The needle is still going straight through the thread, eventually. This is what seems to be cutting the strands on the thread. I can sew for about a minute or so and then I can hear the needle hit the thread.

Any additional thoughts? I read somewhere that when in doubt, get a bigger hammer. I'm not at this place yet, but the thought did cross my mind a few times.

Thank you,

Gene
Title: Re: sewing machine problem
Post by: sofadoc on October 21, 2011, 03:28:00 pm
Are you saying that the needle is going through the TOP thread?
Is the check spring functioning properly?
Are you sure that it isn't the hook that is piercing the top thread?
Title: Re: sewing machine problem
Post by: SHHR on October 21, 2011, 04:22:03 pm
Once when winding bobbins I accidentally let the needle bar hit the foot while in the up position. My thread started cutting and fraying real bad. I first thought I had a bad run of thread then it was doing it on any thread I used. After a lot of frustration and words I won't mention on here, I discovered a small burr on the needle bar where the thread feeds through down to the needle. I used a small round file and took care of it real quick and no more cut thread.
Kyle
Title: Re: sewing machine problem
Post by: JuneC on October 21, 2011, 07:49:53 pm
I've also, on occasion, used 1500 grit (from Bennett Auto Supply - Home Depot doesn't go that fine) wrapped around a round toothpick - with the grit side out - to smooth the hole in the foot where the needle/thread passes through.  Works to also polish the hook itself if you believe it may be a bit rough.

June
Title: Re: sewing machine problem
Post by: josh on October 21, 2011, 10:54:01 pm
check the hook with your finger rub the tip gently if it is not completely smothe then use a smothe sandpaper to bring it to a smother edge
Title: Re: sewing machine problem
Post by: gene on October 22, 2011, 05:40:28 am
I saw the needle tip piercing the thread which is why I thought the needle tip was doing the cutting. Now that you folks have mentioned barbs and ruff spots, I will definately check that out. I don't think I would have thought of this.

I will let you know what I find.

Thanks.

gene
Title: Re: sewing machine problem
Post by: scottymc on October 23, 2011, 03:33:47 am
It happens to my toyota now and again, the needle gets pulled of line and hits the hook, putting a burr on the hook and cutting the thread, I usually take the hook off the bobbin case and use emery paper to smooth it out and after I screw the hook back on I have a cloth polishing wheel I bought for my grinder to polish it right up, it's worth the money to get one , even just to make sure there is no burr on the screws and if you are pulling the machine apart you might as well do it properly.