Juki DSC 245-4 bobbin issue

[BettyJ]

Hi all

*sigh* I've spent all day today trying to figure out what is going on with my Juki. It's usually a rather well behaved beast but today, it's being a real pain. I have someone coming out to service it tomorrow but I'll be at work, which is annoying. I'd like to be present so I can annoy them with questions, more so because this is the first time someone is coming out to me in Singapore. I knew my guy in London, I don't know this new person or if they're any good. Could easily be $85 down the toilet.  

In the meantime, I still want to try resolve it (because it's quietly driving me insane that I can't fix it when I can fix everything else!), does anyone have any ideas as to why my bobbin keeps getting a loop like this every few stitches? I'll be sewing along just fine and then my bobbin, which is perfectly wound, gets all tangled up and then this happens. I'm truly at my wits end. I'm going to go drink coffee, swear and surf the internet for a little while till my temper comes back.

Also, I've rethreaded a thousand times, I've rewound the bobbin, I've oiled the machine (thinking to get on her good side), I've adjusted tension dials, the bobbin tension and I've read the manual to make sure I actually did thread it right and to get some help on troubleshooting. Manual was written in 1987 so she's getting on a bit and it wasn't very helpful.

Thanks in advance for the help. Sympathy also welcome.  

 

P.S. If she doesn't sort herself out, she might well get traded in soon.  

[RockyAussie]

I hate to sound silly but can you confirm that , that is the bobbin thread showing in the loop there? Brian

 

[BettyJ]

5 minutes ago, RockyAussie said:

I hate to sound silly but can you confirm that , that is the bobbin thread showing in the loop there? Brian

 

It's ok, I'm willing to answer any question to find out.

Yes, that's the bobbin thread, or at least I think it is.   It only appears occasionally, as I've slowly hand turned to see when and how it pops up. It sews perfectly till this happens

Edited January 9, 2018 by BettyJ
missed a bit

[RockyAussie]

When you pull the loop does it feed out of the bobbin and the bobbin spins or pull down from the top?

I have never had a bobbin do this at slow speed myself.

[BettyJ]

1 minute ago, RockyAussie said:

When you pull the loop does it feed out of the bobbin and the bobbin spins or pull down from the top?

I have never had a bobbin do this at slow speed myself.

I think it was coming from the bobbin itself. But I'll go check now. Two seconds

[BettyJ]

I was wrong, it's coming from the needle. I pulled it when it happened again. I notice a strange clicking just before it happens, and then my bobbin gets a bit jammed up, I can see the threads doing something weird

[Constabulary]

First thing I usually check is if the needle / hook timing is correct - when you hear a clicking sound - is it possible that the hook tip hits the needle at a too low point or does the needle hit the hook somewhere? Is the hook grabbing the thread loop at all? Any chance that you can post a a video?

[BettyJ]

2 hours ago, Constabulary said:

First thing I usually check is if the needle / hook timing is correct - when you hear a clicking sound - is it possible that the hook tip hits the needle at a too low point or does the needle hit the hook somewhere? Is the hook grabbing the thread loop at all? Any chance that you can post a a video?

Hi Constabulary, thanks for replying. I have no idea how to check this unfortunately. I have someone coming out tomorrow so I'll get them to take a look at it. It's just so weird as it worked perfectly just last month and I haven't touched it since then as I've been away. Must have been gremlins in my flat while I was on holiday.  

[Constabulary]

Better let some professional check the machine if you don´t know what I mean.

Maybe this engineer manual will help you a bit:

Juki 245 Engineer's Manual

Edited January 9, 2018 by Constabulary

[RockyAussie]

14 hours ago, BettyJ said:

I was wrong, it's coming from the needle. I pulled it when it happened again. I notice a strange clicking just before it happens, and then my bobbin gets a bit jammed up, I can see the threads doing something weird

Sorry I disappeared last night on you. My wife got back with the groceries and managed to lock the keys in the car when she got out of it. Many hours later we saved the meat and ice cream etc. As Constabulary said this could be a timing issue and probably its best to let the experts look into it. Hope to hear it all sorts out alright.Brian

[BettyJ]

Hi guys

Thanks for the help.

I had someone come round yesterday and thankfully, they heard the thunking that I mentioned and managed to fix it. My husband was at home with them, as it was my first day at a new job. So it was a little tricky to try to manage this over the phone. Ah well. It's done and fixed and when I get home tonight, I'll be testing it out big time. Was so shattered last night and my brain felt like it would explode so I didn't dare touch my newly fixed machine.

Thanks again for the advice.

 

[BettyJ]

Ok so it seemed that they had it fixed but my bobbin still gets a bit jammed up every so often. I can almost hear when it's about to happen. I will have to call them out again to see what else is going on.

In the meantime, can anyone shed their years of experience on what they think may be happening? I've attached a copy of pics of what it looks like front and back. The front looks fine, the back does not. My finger is on the front picture.

Thanks again for the help.

[Constabulary]

II would check the thread path and maybe try to in crease the top tension a little bit and probably check if the thread regulating spring is well adjusted.  (just a guess). See picture for regulating the spring

[BettyJ]

48 minutes ago, Constabulary said:

II would check the thread path and maybe try to in crease the top tension a little bit and probably check if the thread regulating spring is well adjusted.  (just a guess). See picture for regulating the spring

 

Thanks Constabulary.

From the diagram, it looks like it this screw here on mine. What do you think? You think I should just back it off a bit and see? Willing to try anything right now.

Also attaching a picture of my thread path too. It's as per the manual for threading so that's all good.

 

[Constabulary]

Thread path looks good. Your tension unit looks a bit different to what I have seen. There should be 2 screws - one is for the spring rest (front screw) and the rear screw is holding the tension post in place. If you have to adjust the regulator spring travel you have to loosen the front screw. The spring rest usually it a curved metal tab that is mounted behind the silver disc with the long nut. You can slide the curved tab back and forth when you have loosen the screw. Check if you have that cured tab but maybe the spring rest looks different on your machine - can´t really tell from the pictures.

One more thing - do you have a knee lifter for lifting the presser foot on your machine? It sometimes can happen that you slightly push the knee lifter (even if you don´t want to) while sewing and that already can cause a top tension release and the thread knot shows up on the underside. If you are using a foot pedal for lifting the presser foot take your foot off the pedal while sewing.

Edited January 13, 2018 by Constabulary

[RockyAussie]

Just check that while the bobbin is set up on the machine that you get an even pulling feel on the bobbin thread as you pull it out. If you get a feeling of snagging meaning loose and tight then you may have grit on the bobbin shaft or the bobbin case or the bobbin may have some damage. Also along with the points constabulary mentioned make sure the thread back at the cone is coming of without going loose and tight as that is also a common problem.

[BettyJ]

Thanks so much guys, I think I found the culprit. There was a tiny piece of thread behind my thread take up dial which was causing my stitches to jump about and jam up. Since I removed it, it started working perfectly again. Took forever to get the spring back on properly but I think I'm all good now. I'm almost too exhausted to sew!

[RockyAussie]

I am glad if you found it as I would never have thought of that one.. Good thing is you never stop learning in this LW game.

[BettyJ]

The technician didn't either so I'm feeling a little bit clever at the minute.   I wasn't feeling clever when trying to get the spring on but at least it's done now.