Tuesday, May 25, 2010

It's a Juki Disastro

NOTE: Scroll down for updates & fixes.

Well, not really a disastro ... I've just been listening to CocoRosie lately.
Though, my brand-new Juki DNU-1541S is still not working and that's close to a disaster.

After hours of contemplation and watching the hook spin round and round I've figured out that the hook assembly is most likely defective, or was damaged somehow at the factory. Either way, there's a rough spot in the rotation of the hook that causes the assembly to seize up when there's enough lateral pressure applied to it.

Hook assembly pictured above. The inside part with the post is called the basket. It rocks back 'n' forth slightly while the hook rotates around it and is held in place by the bobbin case holder.

The first time I was sewing with this machine, I was going slowly over some number-eight cotton duck, everything's going well, beautiful stitches ... sewing over a few more layers of duck on top of that, and then boom! the machine jams up.
I thought it must've been a bad needle strike, or something like that, and the safety clutch went off. But it wasn't that at all. It took me a while to figure it out -- days -- but here's what's going on:

When there's force on the basket, such as when the machine is handling heavy material, the basket and hook lock up. This makes the basket pop outta place and rotate with the hook. (Note the top red arrow above: This is the li'l nubbin that keeps the basket in place [the finger on the bobbin case holder]. With the second arrow, above, you can see the needle coming down through the slot in the basket.)
Here the basket has popped out of place and is rotating with the hook. The needle is continuing to descend...
...and will collide with the basket ... now! Your needle will now be missing its tip and your case opener (that lever on the bottom of the photo) will now be pointing to the right, knocked outta place.

The great tragedy of this is that Juki sewing machines have such a good reputation that no one believes me when I tell them that I'm having trouble with my hook assembly. They usually try to blame the problem on me, or tell me to call someone else ... in circular fashion.
And since this only happens with heavier material, it wasn't caught at the factory during the final sew off.
Fortunately, Juki America has been fairly helpful, and I've sent my hook in for inspection.

Note: I've received my replacement hook and I've just installed it. So far so good. Thanks, Juki! [Keep reading for more updates.]

Though, I swear this machine must be cursed. First I received a defective table leg, then the motor belt was too small to match the drilled holes, now a crummy hook assembly.
Sheesh. Give me a break.
Lucky I still have my Tacsew 111. Almost half the price and sewing strong.

So here's me taking the hook assembly off (don't do it like this -- the whole thing comes off w/o taking it apart):
I was hoping to just move the feed base up a bit and slide the whole assembly out, but the thing's so complicated on this machine, I just took the assembly apart and got it out that way.
[Note: I figured out you can just loosen the bobbin finger/holder (that piece with the nubbin on it) and swing it out of the way and that leaves just enough room for the hook assembly to slide out. That's when the feed dog is at its highest point.]

Above and below is the hook with no basket.
Made a li'l mark on the machine so I can roughly line it back up ... though, there's a groove in the hook shaft...
[Note: Lucky there's a groove 'cause I forgot what position the needle was at. You need another reference point, otherwise this is useless. Ha.]
Needle plate removed. The hook just about to come back up. This is where the hook would snatch the thread loop.
No more hook assembly.

Update (5/10/15)
Probably should've updated this years ago, but I only use this machine occasionally now, mostly just for thick foam applications ... but I've recently received some emails from people with this same problem and seen this problem come up on some forums, so here it is:

After I installed my new hook assembly back in oh-10 I still experienced the dreaded hook jam, though not as much as with the original hook assembly. I've thus concluded that these hooks are bad -- bad to the bone. [If I can't get other hooks in other sewing machines to jam the same way by pushing on the bobbin, and I can with the 1541S, there's definitely something wrong with this hook, but maybe that's just me.] Though, I've figured out a way to work around this issue. First, let's look at the threading diagrams for the 1541 and 1541H (heavy duty):

Above is the threading diagram for the 1541 and 1541S (safety clutch). Note the sliding thread guide (red star). This is used to adjust how much thread goes around the bobbin -- or something like that. I can't find it addressed specifically in the manual.

Now look at the threading diagram for the heavy duty class. No sliding thread guide! This is key. Here's what I think is going on:

These machines are set up to sew through a couple layers of upholstery material, and when you go to sew through anything heavier, there isn't enough thread to go around the hook assembly smoothly, putting inward force on the bad bobbin basket, which then binds.

To avoid locking up the bobbin, I've been threading the machine the H way (or similar) with good results. This is how I was threading it the last time I used it, sewing 1/2-inch closed-cell foam and Cordura. I've skipped the sliding thread guide and the square thread guide, leaving plenty of thread to travel around the bobbin.

Notice the sliding thread guide is oriented the wrong way. I'm pretty sure threading it like this will actually take up more thread. I was playing around with different guide configurations a while back. I should set it back the way it was...
Here is another look at the hook assembly and related parts. Juki has a real nice database. You just need to set up a user name and password.

If this happens to you, the hook assembly will catch the needle and the machine will jam. If you're sewing at speed, your needle will shear off. Clean out your ruined needle and thread and turn the handwheel backwards till the hook assembly pops back into place on the finger and then look for issues (you will most likely have to reset the case opener lever (on an S class). You may have to adjust your threading, as shown above. Or it's possible thread has been pulled into the hook raceway and caused the jam.
This might be caused by another issue, brought up by a sewing tech on Upholster.com (2/7/11):

Re: JUKI 1541-S shuttle/hook assembly out of whack, help me fix it!

I know exactly what is wrong, and I can explain how I know; because I check every Juki DNU-1541S before it leaves my shop for this known (by us) issue with this model, out of the box.
I can't tell you how to fix it, as I do not care to go head to head with another sewing machine mechanic. They may have a different resolution to this that I do, and I don't want to get into a tit for tat, he said she said brouhaha.

But, I can tell you what I know for absolute sure; the hook supporting plate/bobbin case finger that holds the bobbin case/inside hook from spinning is hanging on by a finger nail, and does not go in far enough. Unless this is taken care of, this will be an issue that will continue to plague this machine.

I've reset my hook placement before, and tested it by hand to make sure it was solidly engaging with the finger, and still had it pop off. There is quite a lot of force behind that hook when it jams. The finger-placement problem explains why it comes freely on certain 1541s, though -- and is maybe further proof of a larger quality issue with these machines.

And here is a thread on Leatherwork.net where the hook assembly popped free.

I'm hoping, as I use this machine more, the hook breaks in and never does this again. I oil my hook manually now, and I'm pretty cautious when I sew heavier stuff. Hopefully one day I can relax while I use this machine. :)

Update (5/25/16). I've been informed by a sewing machine mechanic that there is a break-in period for hooks -- even high-speed Juki hooks. He recommends turning the hook oiler all the way up.

Update (6/30/20, Year of the Covid). I've had a request on how to adjust the bobbin case positioning finger (that thing with the nubbin that keeps the bobbin basket in place).

The idea here is that you want the nubbin to go into the bobbin-basket notch far enough to keep the basket in place if there's some friction in the raceway, but not too far that there's no room for the thread to pass around the nubbin. You'll probably have to do this through trial and error. It's possible that if the basket has popped out a lot, your nubbin may have been damaged and you'll need to secure a new finger.

Here's what that finger looks like outside of the machine:

And here's where the screw is that allows you to adjust the finger. Again, don't take your hook apart to get it out ... just remove the finger.

Good luck!


Unknown said...

This blog post is amazing! I work at a sewing machine dealership in CoMO, and I LOVE how well you've explained all this. I also know a guy who services industrial machines, like you Juki and can get parts for them. ROCK ON!!!!
Oh, and I feel like we are kindred sewing spirits in a way, because ever since I was 15, I've been sketching (both on paper and in fabric/thread) out the perfect bag for all my needs. Lots of products have emerged, but I can sense that making the perfect bag for other people would be extremely satisfying.
And if you need a job as a sewing machine technician, I think I know where you can find one ;)

Mallory Donohue
Zede's Sewing Studio

cory said...

Thanks, Mallory!

Eric said...


Thanks for the great blog! Love the 1541S build post.

Can you tell me how the 1541 was fixed? I am about to get my new 1541s and want to double check it as I assemble to make sure there's no problems. I have actually been reading that there are a few of these machines with hook problems out there. Just want to be safe!

And finally, how are you still liking the 1541s? It is your main machine? Love to know.


cory said...

Hi Eric,
I received a replacement hook from Juki. It was doing pretty well for a while...then it started locking up the same way. The only two things causing pressure on the hook assembly are the thread and the case opener. I think sometimes the thread was too tight when it was coming around the case. You adjust this by sliding the skinny thread guide up or down. When I'm sewing 1/2" foam I'll take the thread out of that guide so there's even more thread available for each stitch.
I also disengaged the case opener in case that was causing trouble. I think the opener really only helps when using heavy thread--heavier than 92. My 111 doesn't have one and it stitches great.
I haven't heard of anyone having this sort of problem before and I've been looking for a while (though maybe in the wrong places). I still find this problem extremely weird and still don't understand it fully. Though, for a bit, I installed a 241 hook in the 1541 (they're fairly compatible) and never had it jam. In the older hook the thread-cutting grooves in the hook raceway are cut diagonally, while on the current hook the grooves are perpendicular to the raceway. Just a thought. Though there could be any number of other reasons for this...

Yes, the 1541 is my main stitcher. It's a great machine when it's behaving--the foot lift on it is awesome. Though I still use the 111 a bit too...it feels more comfortable to me.
Anyway, I'm sure you won't have any problems with your 1541S. Just make sure the hook is lubed and make sure the thread guide is adjusted to suit the material thickness. Also remember to hold the thread ends when you start a stitch--the Juki is touchy about that.
Have fun with your Juki!

Eric said...

Oh! I see what you mean about holding the thread ends on the 1541. Dang loops! I thought I was going crazy there for a moment, thinking my bobbin tension was too loose...

Is your needle tension on the 1541 super tight? Mine seems to like it very high. I'm going through two layers of nylon tube webbing and it seems to be really pulling the fabric together more than I'd like. Maybe I need to work with tensions again...dang! How are your tensions setup?

Thanks again for the great blog. Hope all is well.


PS No bobbin issues to date. Zamir set everything up before it was sent out. Seems like a good guy to work with.

cory said...

I don't think my tension's super tight. First of all I'm using T90 thread. If you're using much heavier it's possible that you might need to loosen the bobbin tension.
For heavier stuff I tighten the dial down till can see one or two threads of the post. For lighter stuff I back up till the post end is about flush with the dial.
Needle size can affect tension...if you're using too big a needle you can get wonky tension.
Hope this helps.
Lemme know if you have any other questions. You can email me at coryleif@gmail.com
Happy sewing!

Unknown said...

Wow ... Reading through this I suffered with you with all the staring problems you had with your machine. I probably would have given up. Actually it make me think .... Waht odd you do, if you have a problem that you can't figure out yourself. This kind of machines are not very portable to take them on the backside into the next towns service place..


cory said...

Hi Martin,
Yes, this is not a fun situation...especially with a new machine. You just try to be patient and figure out what's wrong and how to fix it and hope you get it right.
Juki is more helpful than most large sewing companies, I believe.
I've since found Leatherworker.net, a great forum and resource for industrial problems. Among its members are a number of shop owners who answer questions. Though, sometimes a machine is in so much trouble you have to ship it to a pro. Fortunately I haven't had to do that yet.

Shannon said...

I just want to say THANK YOU so much for this post. My 1541S broke down yesterday, today is Labor Day and I was desperate to get it going again. I looked all over for information because I knew the problem was in the hook but my inexperience kept me from figuring out where the problem was. You're awesome pictures showed me what needed to be fixed and I got it going again! I can't thank you enough for the great pics and explanation of the key factors to make it work properly. YOU ROCK!

Tia said...

This is mee to the T! Just brought my Juli 3 days ago and have the exact same problems.took it back 2 times and all the time they blame me! Did i drop it they ask! No! And I cant convince them its not me its the machine

rchauffe said...

Great info, thanks for taking the time to post. Same issues!

What did you mean by disengage the opener for lighter threads?


cory said...

By "disengage" I meant I didn't reset it. It's hanging loose, touching nothing. Its purpose is to push on the bobbin case and make sure there's a gap up top so the thread can pull smoothly around the bobbin case finger. With lighter threads there's more room, so it's not an issue. As noted, the safety-less 1541 does not have an opener. Though, I should probably reset mine some day...
Good luck!

Gailerson said...

I have to start by saying I love you. Your blog has calmed my shattered nerves more than once. Will you throw out a few thoughts as to why I can't pick up the bobbin loop on my 1541S? Timing is good, finger tightened. Opener adjusted...I think.....

cory said...

Hi Unknown,
Glad the blog's been helpful!
If you can't pick up the loop, try these things: Put in a new needle. Make sure the needle is inserted correctly (all the way in, groove facing left, thread going in left to right). Make sure you're holding onto the end of the needle thread when you're picking up the loop. Double check the threading on the machine all the way back to the thread stand. Make sure you have proper needle-thread-size compatibility. It's usually something small and simple that's causing the problem. Hope this helps! If you have any other questions, email me at coryleif on g-mail.

Ocean Lover Maine said...

OMG.. this is exactly my problem Basket case comes loose and spins around, needle breaking, etc. New machine. I need to contact Juki!! Thanks, I'm not crazy.

sstanek said...


SO glad I found your post! I am a brand new owner of a 1541S & have the exact same problem you describe! Can you tell me how to get a new part from Juki once I remove it?

The guy I bought machine from was blaming operator error, too !!!!

How can Juki send out a faulty machine! Just my luck... I got one that was taken off the assembly line on a Monday or a Friday!

cory said...

Hi sstanek,

Yeah, there's nothing more frustrating than a brand-new expensive tool not working right.

I think I just emailed Juki after I called the shop I bought it from ... and then his supplier and then I dealt with Juki directly ... they were like, Whatever ... but then I sent 'em this blog post and they were like, Oh... That dude could be retired by now, though. It's been ten years! I would try giving them a call. Last I heard, Juki was pulling out of the US market a bit ... as the US rag trade is nearly dead.

I think an important thing to keep in mind for us amateurs/artisans/hobbyists is that these machines are designed to go into a production setting, or at least an upholstery shop, where there's a mechanic available, in-house or on call. A lot of new machines need some degree of fine-tuning for their specific application.

The new hook I received was marginally better than the stock one -- it still jammed up under the right conditions.
I think the lessons here are:

1. What the hell, Juki! 2. There is a break-in period with these hooks ... keep that hook super oiled, don't push the machine outta the gate. 3. If you're sewing over 1/4", thread it like the H version. And, 4, most importantly: adjust the finger so it's seated further into that basket slot. Over the years, there's been a sort of sad comfort in knowing that I'm not the only one with this problem. And some SM shops, like Keystone, in Philly, that deal with this machine a lot and have great customer support, know that this is an issue and adjust the finger accordingly before sending it out to people like us.

Email me at coryleif a t g m a i l if you have more questions. Good luck and happy sewing!

rchauffe said...


Thank you for continuing to address questions and assist others. It's ironic that I just started to get back to my machine in the last week, and this thread pops up in my email!

I was wondering if you know what may be causing inconsistent stitch length? I cannot sew two seems next to each other and keep the stitches lined up.

Also, from the most recent post; What is H threading and setting the needle further into the basket slot? Do you have any photos?


cory said...

Hi rchauffe,

Inconsistent stitch length might have to do with not enough foot pressure or feed dogs being too low ... causing the material to move around as it's being pulled through ... or there's something loose or gunked up on the machine. Since this model's is not a full rectangular feed, there will be some variation in stitch length as the thickness of material being sewed changes, but it should be consistent in parallel lines.

H threading: See the two pictures above comparing the 1541/1541S thread path with the 1541H's. The H subclass is missing a thread guide. I believe not threading through this guide results in more thread slack being able to go around the hook while sewing thick materials.

I'll find some pictures on how to adjust the positioner finger and the bobbin basket. I don't have the machine at my house right now and what with the Covid on the loose, might be a day or two, but I'll update the post with some relevant pics.

rchauffe said...


Thanks. I found the pictures on the website. For some reason, I had a text-only version of the blog on my screen. Again, thanks for the help.


cory said...

No problem, Ron!

Just updated the post to include a how-to on adjusting the bobbin case positioner finger (it's at the very bottom of the post).

Happy sewing!


Patsy said...

That sounds like my problem what did she do to fix it the remedy?

cory said...

Finger adjustment, thread-path variation for heavy material, and plenty of oil. :)

Lauren said...

Thanks for your post & all the detals regarding the issues you were having! Sounds similar to what I am encountering now. My handwheel is completely locked as is my needle shaft. When I take out the position finger down by the bobbin, everything is able to move...it's as if that nubbin is blocking the bobbin from doing its turning. But I know that's the standard alignment for it. I've tried removing & replacing the finger numerous times.

Wondering if you have any advice? I don't see anything stuck or broken in the bobbin area.

cory said...

Hi Lauren,

Wondering if the hook assembly is jammed up. I assume the bobbin case spins round when you take the finger out? (It shouldn't spin.) If you take the hook assembly out does the hook spin freely around the bobbin basket? Feel free to email me: coryleif [a t] gmail.

Unknown said...

Lauren, I am having a similar issue. If you take the finger out and manually twist the bobbin assembly (no bobbin in) around seated inside the hook assembly does it turn smooth? Mine turns smooth for about 90% but then it hits a bunch of resistance. You can also try holding the bobbin assembly still (groove up) and manually cranking the machine to test if it is smooth. I've oiled the crap out of it and it is still this way. When I talked with my local shop they told me symptoms like that mean the hook assembly needs to be replaced. I've only used my brand new machine for about 4 hours total (unfortunately after the warranty period passed :( ). I was able to identify that the bobbin opener was getting pushed out of the way because of the added resistance of the hook assembly and the bobbin opener was stalling the machine when it ran up against the bobbin assembly upside down.

Unknown said...

Cory, thank you for sharing on here!

Do you mind expanding on what Juki told you about the hook needing to be "broken in"? Did they suggest a way to do this?