Juki LU-562 skipping stitches when top stitching a thicker John Deere type of seat material vinyl...

[Wizcrafts]

3 hours ago, JukiFan said:

So, the Juki has been in my possession for 10 years.  I have used it probably 40 hours in making covers for gym equipment. 

Normally, I would use the 69# Nylon with a 135x17x18 needle.  It never skipped stitches with my previous material which was thinner.  With the newer 1/16" material, it happens.  I switched to a 20 size needle before I came onto this forum.  

It could be that I am not pulling both sides of the seam tight enough before trying to apply the top stitch???  Like I mentioned before, the shop who sold me the vinyl told me that another upholstery professional told them the material was impossible to top stitch.  I asked for more info and they had little to say.

My O.C.D. tells me that I am missing an adjustment or something.  

So, if I switched to the 135x16x18 needle, would I need to adjust the timing?  Vinyl is the only material that I will ever sew with this machine.

Start by using a Schmetz Serv 7 system 135x17 needle. I don't recommend #69 thread for this thick seam job. Move up to either #92 or #138 thread, top and bottom (or maybe 138 top and 92 bottom). If you go with #92 thread, use a #19 needle for a tight stitch, or a #20 needle for a bigger hole and easier knot pull-up. If you go with #138 thread on both sides, use a #23 needle. For 138/92, use a #22 needle.

No matter which thread and needle you choose, crank down the presser foot screw to squish the material and get any wrinkles or fluff smoothed out.

You might have to lengthen the stroke of the check spring and add some more slack thread via the check spring adjuster.

Finally, the timing my be borderline for this thickness and density.It's a good idea to open the bobbin cover plate and watch where the hook is in relation to the top of the needle's eye on the upstroke. Also, look at the loop and make sure it isn't dissolving before the hook can pick it off.. Normally, the point of the hook intersects the needle in the scarf about 1/8 inch above the eye. It should have a big enough loop to easily grab it and carry it around the bobbin and shuttle. Maybe your timing is retarded and advancing it will both resolve the skipped stitches and any snapping sound as the top thread goes around the bobbin case/shuttle.

[AlZilla]

Is it possible that between the slightly larger needle and the fabric point punching thru the sewn material that there isn't enough friction between the needle and vinyl to hold the thread down, so the loop can form consistently?

@JukiFan, does the speed of sewing have any effect on how often it skips stitches?

[JukiFan]

9 hours ago, kgg said:

Simple answer, No. The difference of going from a fabric needle (135 x 17 ) to a leather point needle (135 x 16 ) is the tip of the needle. The fabric needle (135 x 17 ) will attempt to push a hole through rather then slice a hole in the material. You will have to check the top thread tension, bobbin tension and presser foot tension. Also a bonded polyester thread would probably provide better UV protection then Bonded Nylon thread.

kgg

No is good!  So, I have placed an order for the 135x16x18 needles from Amazon (for convenience).  What weight of bonded polyester thread?  Where would you purchase?  

[kgg]

26 minutes ago, JukiFan said:

What weight of bonded polyester thread?  Where would you purchase?  

Since you ordered #18 needles order V69 which you get A&E thread as well as others from wawak,com. 

kgg

[Wizcrafts]

On 1/22/2026 at 6:46 PM, JukiFan said:

No is good!  So, I have placed an order for the 135x16x18 needles from Amazon (for convenience).  What weight of bonded polyester thread?  Where would you purchase?  

Here is a thread and needle matching chart that I had a hand in creating. Where two sizes of needle are shown, use the smaller size in thin or soft material and the larger in thick or denser material. When it comes to the accuracy of the thread sizes, trust the name brands over no-name spools. Name brands have some degree of quality control. Avoid the cheapest thread (e.g., off-brands on eBay or online Marketplaces). 

The thread chart includes the strength of each thread size. This is its breaking strength. That can be used to determine the best thread for a particular job. For instance, if you are going to seam a cover that will be pulled tight over an object, or otherwise subjected to stress along the seams, use one size larger that the smallest thread. It might be a little harder to totally hide the knots on the backside, but the stitches may hold up better. I usually use the largest thread that allows me to bury the knots.

 

There will also be different compositions of thread available to you. Choose the type of thread that fits the material. If you're sewing denim, you can buy a type of thread called Denim Thread. It's washable and stable when washed and dried. If you're sewing indoor upholstery, buy bonded nylon. If the job is for outdoor use, like a porch chair, or an awning, outside banner, or a cushion on a boat, use bonded polyester thread that's UV resistant.

[CowboyBob]

@JukiFan There are quite a few reasons for skipping but one very overlooked one is a wore our needlebar,from tightening the needle set screw over many years the hole gets enlongated to the left side forcing the needle to set @ an angle so the thicker your sewing as the needle goes in it will pull it away from the hook causing skipping.The test is loosen the needle set screw & note how far it moves left to right.

[JukiFan]

Thanks everyone for your taking your time for suggestions & insight!!!  I am going to order some different needles and thread. If the skipped stitches continue, I will do the suggested adjustments.  

I am snowed in for the next couple of days.

Please consider this thread PAUSED for the next week until needles and thread arrive and adjustments are made!!!

[JukiFan]

Update...Okay, I ordered Amann TEX 90 Outdoor Pro Polyester Bonded thread and pre-wound bobbins from Wawak.  Also, I ordered Schmetz Leather Needles:  135x16x20, 135x16x21, & 135x16x22.

I threaded the machine and tried out all the needle sizes.  The result was frayed polyester thread on top near the last thread guide and the needle.  The poly snapped several times as well.  Tension could have been too tight...or it could have been a burr...or a combination of them both???  Played with different tensions for about 2.5 hours. Never could get it right.  

Became super frustrated, put back on the 69# Nylon and tested with various needles (the leather needles as well as my existing 135x17 in size 18, 20, & 22).  Eventually, the 135x17x18 worked best. It might be working better than before.  The topstitching isn't skipping stitches like before.   

So, any idea on why my machine hates Poly?

 

Edited Saturday at 02:38 AM by JukiFan

[friquant]

On 1/21/2026 at 8:22 PM, friquant said:

An informative exercise would be to put something like that cushion seam back under the machine so you can see some skipped stitches as they form. With the material under the presser foot, tilt the machine head back so you can see the underside of the machine. Get a good light or a flashlight, and reading glasses if they help. Then turn the handwheel by hand to make slow stitches, but watch what's happening from underneath. Pay attention to what it looks like when it actually makes a stitch, and to what happens when it skips. Let us know what you see!

A skipped stitch is a full miss. Guess what a half miss is......it's frayed thread. If the needle is too far away from the hook on that particular stitch, it will skip. If it's not quite that far away, the hook point will attempt to bisect the thread, resulting in a fray. Sometimes frays correct themselves (as is the case with UNbonded thread if the hook point gracefully catches one or two strands but not all three). Other times one or more strands break and you are left with a mess.

Once you've tilted the head back and watched some skipped stitches (or frayed stitches) happen in slow motion, you will understand more of what's happening. And with thick material, the needle doesn't come down in the same place every time. The best defense against this phenomenon is to stuff the hook.

[AlZilla]

You don't mention if you looked at the check spring, suggested earlier.  Here's a recent treatise on all things Check Spring from Wizcrafts. Proper check spring function is critical: