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Member since 10/22/18
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Posted on: 4/23/20 7:04 AM ET
Updated

One of the pins underneath the needle plate is bent right down. The other, the right one looks fine. The dealer is going to get a replacement needle plate for me rather than replacing the pins. Apparently these are not under the guarantee since they call it accidental damage but they are going to replace it free of charge on this occasion.

I am mortified that I have owned a serger for 1 month and something has happened that is called accidental damage. I can't understand how this has happened particularly in such a short time.

When I changed the thread and tested it out on scrap fabric it was stitching fine but not cutting (it was only a narrow piece of fabric) so I moved the fabric over slightly and this is when the problem began. I had moved the knife out of the way to thread up and had forgotten to put it down. Just at the point of moving the fabric it got stuck and I stopped. I then had to remove threads using a small stitch cutter and tweezers. So I re threaded and began the test again with the knife down. I had thought about changing the needles just in case one had got bent but didn't. They broke when I tried stitching. I found the pieces. It is possible that one of the threads (green) was not in the tension disc properly or that the presser foot was down. I changed the needles and re-threaded. I was then confident that everything was done correctly. The knife cut but stitches didn't form but looped around and got stuck.

I see these as beginner errors that anyone can make from time to time. Are the pins that delicate that they break after such a short time. My machine was a demo model that had been checked out before sending to me.
-- Edited on 4/23/20 at 9:23 AM --
  
Member since 5/2/09
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Posted on: 4/23/20 2:14 PM ET
They are kind of that delicate just there, compared to sewing machines.

So, on a sewing machine; if you end up getting a sewing/stitch jam up, and the fabric tries to get sucked down the stitch plate hole, you can lift your pressure foot to attempt to release thread tension, and then rock the fly wheel back and forth, to try to release the stuck threads, while slowly pulling the fabric out of the machine in pretty much, any direction you wish- forwards, backwards, side ways....... it does not really matter in which direction you do that. It might not always work, if it's real bad, you still might have to take the stitch plate off or cut it out- occasional.

Serger is pretty different......... because of those stitch pins in the plate. And because all the stitches get formed over them. And they are only open and not attached to anything on the back side of them. So the only way fabric trapped by stitches onto them, is going to get off of them is by the fabric moving towards the back of the machine and away from you sitting in front of it. And sliding off of them that way. So, if bad things happen and you get jammed up- if you try to pull the fabric out forwards, or sideways, or upwards, or downwards, it can't really happen- (since it's stuck on those pins) and something has to give - or not and it will just stay stuck there. So the thing that might give, can be the stitch pins getting broken off or bent up. Plus needles hitting them will do that too. Not every time, but sometimes.

It's nice that they are sending you a new plate. After you got the new plate and are using that instead, you don't need to throw away the old one. Just keep it, instead. You might be able to, possibly unbend that bent down stitch pin with some needle nose pliers or something, but also a good chance it will just break off if/when you try it. But, once you got the new plate, not much to loose on just trying either, with the old one that you can't use as is, now anyways. But it would have to be straight and smooth also there to work, and not have thread and fabric get hung up on it, and cause a problem, kind of all over again.

Another reason to keep it, is in case it keeps happening to you, or ever again, is sometimes you can actually use a cut off hand needle or such, wedged into and glued into the slot the original stitch finger was in. As a make shift replacement even. A new stitch plate is always better though. So, that is first choice and sounds like you are getting one. But, keep the old one too, just in case, you really ever get real stuck and really have to do that. Sorry that happened to you, but you are not alone, that kind of thing, happens to people-it's happened to lots of people. But, now maybe you know more why it happens, hopefully you can keep it from happening better even.


-- Edited on 4/23/20 at 2:25 PM --
  
Member since 3/24/04
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Posted on: 4/23/20 6:43 PM ET
In reply to sewing4therapy
Yup, it happens. As Beau says, ask the dealer for the old part and spend some time looking at it... one of the stitch fingers (the one most likely to bend or break) is a hand sewing needle on most machines, and if you take the time now to measure and fit in a new needle of the same size (use something like Superglue, cyanoacrylate that can be removed with acetone), you can replace the bent one with a new one. I'm pretty sure they're either betweens or sharps, but I'd have to get out the micrometer and measure to decide the size... does your DH have one? I'd measure the one in your new plate, and then try replacing the damaged one in the old plate once you can shop for hand needles easily again. Or: https://www.jjneedles.com/needles-guide

So far, knock wood (thumps on head), I've not managed to mangle a stitch finger. But I was taught early that after you did anything on your serger in terms of moving the knife, rethreading, whatever, you a) really *looked* at the machine to see if anything looked "wrong" for the usual serging I do (which is when I typically catch that I've left the knife up), and to make sure that I start chaining *very* slowly

A single strand of serger thread isn't all that strong, but an aggregate of 4 threads is; and the stitch finger, like the needle, is engineered to bust before the expensive parts of the machine do.

So... not a tragedy, but a learning opportunity. Don't let it put you off serging. Just remember to check to see if things look normal for what you're going to do before you do it.
  
Member since 10/22/18
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Posted on: 4/23/20 9:30 PM ET
In reply to kayl
Thanks for your post. DH says I do not have AME (Advanced Mechanical Empathy). The new plate is coming in the post and DH is going to do it. I understand it takes just 2 screws to install. The importers said to get the timing redone too but the dealer thought it was unlikely to have upset the timing and to see what happens once the needle plate is changed. DH had in mind to keep the old one and has already thought about fixing it. When I was looking for the broken needles I did see the bent over finger but didn't know what it was then. It felt very strong and thick unlike the hand sewing needles I have. They do look like needles. I have found the dealer very good and glad I went with them their customer support has been excellent but it is some distance away and will cost a bit to get a courier to pick up and collect.

The importer and dealer seem quite sure it was the mangled thread and a tiny bit of fabric that bent the left finger. I can't see that myself because it was so little. I have forgotten to put the knife down before. I didn't think it mattered. Sometimes I just want to overlock without cutting and thought having the knife in its cutting position was optional. What did seem a problem to me is that loads of loops of thread had wrapped around something. I didn't know what having never taken the foot off before. I imagine the loops of thread were around both pins just looking now. I have had to remove these threads with some difficulty a few times. I assumed there was something wrong with the threading then and redid it. My guess is that the needles had become slightly bent. I notice on my sewing machine when I am topstitching or using the stitch in the ditch foot that the needles only have to be out slightly to change the position of the stitching line. If I hadn't been so unsure of how to change a needle or so hopeless at the workshop with the wrong size screwdriver I would have probably changed them. DH thinks it is more likely that the needles bent the left pin on breaking but admits he doesn't know about these machines. I think it was both actions the mangled threads and perhaps a slightly bent needle completely bending the finger over and breaking the needles at the same time. I will be too scared to make a mistake re-threading again. I have managed this part really well and didn't think for one moment that getting it slightly wrong could create damage to the pin. At least I am not too scared to change the needles now. DH says the plastic needle holder is ridiculous because the needles turn around in it while attempting to install them. He found the screwdrivers on my toyota machine that were made in Japan better than the ones that came with the Juki. Could it be that the needles I chose to replace the broken ones are slimmer. I used schmetz jersey needles size 80/12 for medium weight cotton/wool blend fabric. I think it is likely universal schmetz ones were on the machine and there was a packet of replacement ones in the accessory pack. When I went for a demo at my local shop I took various different fabrics and asked about changing needles but the dealer didn't think it was necessary. Whereas I would have changed ones in my sewing machine.
My serger seems very fast to me even when I go slowly to start with. It feels more like I do stopping and starting when serging. The one at the workshop seemed very fast too but I was doing straight edges mostly. I am a bit annoyed about the manual when it states raising the knife to re-thread but I haven't heard anyone says remember to but the knife down otherwise you could damage the pins. I would have expected a warning such as I have heard about don't go over pins you can do untold damage to a serger. So I never pin fabric together before serging. Likewise the importer says he never raises the knife when threading up now at a demo.
I can usually catch if I have miss threaded when looking as you say. I have got scared to try again now particularly if it isn't going to the dealer. I have a local technician but he isn't a Juki expert. I would feel more confident it he changed the needle plate and gave it a spin DH doesn't know about sewing machines. This social distancing/vulnerable household and isolation makes that impossible.
  
Member since 10/22/18
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Posted on: 4/23/20 9:44 PM ET
In reply to beauturbo
Thank you for your comments. We say hand wheel in the UK. Interesting.

I have reread your comments now and they make sense to me thank you. I imagine the needle breakage was the final straw on those pins. I see what DH means now I have no automatic mechanical empathy AME. He wouldn't have done that he would have figured things out before attempting to remove the jammed threads. Whereas I did what was familiar to me after using a sewing machine. He keeps telling me a serger is different.

I appreciate your comments they have really helped me to understand what happened. I guess we could buy some new pins for the old needle plate to keep as a spare.

It was quite a shock doing this so early on. I don't feel I know enough even though I went on a workshop and demo. It feels to scary to get back into it a bit like when you have a prang in your car.
  
Member since 3/24/04
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Posted on: 4/23/20 9:56 PM ET
Here's my Juki without the presser foot or fabric, so you can see how the stitch fingers (the two cylinders that are between and beside the needles) form the stitches:


(If you want to see my "presentation" of the stitch cycle, try cycling through these two albums on "slideshow" with about a 2 second timing)
http://www.picturetrail.com/sfx/album/slideshow/24107012
and http://www.picturetrail.com/sfx/album/slideshow/24107038
and a side view of the foot, with the fingerguard removed: http://www.picturetrail.com/sfx/album/view/24105914

I find doing photo sets like this of any new mechanical object that crosses my path tends to help me when I'm trying to figure out what went wrong, or if something is busted.

Any serger that I've used, with the exception of coverstitch, has been universally happier if the blade is down and cutting. I think what happens if you don't trim at least dust off the edge is that the fabric can start to fold and catch over the edge, and then jam. The amount trimmed can be literally dust... a mm or less... but my experience is they're happier when cutting.

Please don't let this break your confidence. As my DH the engineer says, "it's ok, it's only sheet metal, nobody got hurt", which is a meme he learned from one of his best friends at NASA, one of the junior engineers that was sitting in the circle under the motion base Apollo simulator, figuring out how to invent a CO2 scavenger from the limited parts on Apollo 13, 50 years ago. Amazing what you can do with 12" of 2" wide duct tape when you put your mind to it.
  
Member since 10/28/14
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Posted on: 4/23/20 10:18 PM ET
In reply to kayl
Sorry, I don't understand: why is it bad to serge with the knife up?
------
Let be be finale of seam.
  
Member since 3/24/04
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Posted on: 4/23/20 10:25 PM ET
In reply to janedoe0a
It seems to cause more tangles and the sort of problem Sewing4therapy ran into,
  
Member since 10/22/18
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Posted on: 4/23/20 10:31 PM ET
In reply to kayl
Thanks kayl
I can see the picture without the presser foot but not the others. This looks like my needle plate too. We have had a new monitor and adobe flash is blocked. Will have to attend to that. I will do what the Juki technician suggests and not move the knife again unless I really have to.
I don't know about timings the technician says only trained people can adjust that. Can I make my machine go slower.
I am getting the idea that it is not that bad and how to avoid it happening again. I just find it a bit unnerving that I had to learn this way when something is so fragile. The Juki technician was soon on the trail once he was confident I had threaded and had the needles changed correctly.
  
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Posted on: 4/23/20 10:41 PM ET
In reply to kayl
I am thinking it was removing the jammed threads the wrong way (as beauturbo identified) that bent the left needle plate pin that broke the needles that bent the pin some more. The bent pin points towards the floor now. The right one is in tact.
Glad I have got that sorted.
  
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