The Upholstery Forum

Hi everyone,

I am totally new to sewing and even newer to upholstery.
While trying to set the correct thread tension the first time on my machine after 2 hours of tweaking I stil see the top and bottom threads randomly appear on the othe sides of the fake leather.
I have attached a foto of the problem. The line of stitches at the buttom was my last try. All the above ones are from earlyer tries but the problem is visible on those as well. Please note the white dots (upper thread showing on the bottom side). The bottom thread also randomly appears at the top.

I work on a Juki DNU-1541S
The material is 1.1mm thick fake leather.
I am using a size 19 needle in combination with Amann serabond 30 (V92) thread.

Just for the sake of experimenting I have tried to sew 4 layers of the same material. In that case the dots didn't appear on the surface.
Am I using the wrong material-needle-thread combination or is it something else?
Thanks for any help in advance!

Normally I set tensions with 2 layers of material. I also fought tension with single layer. I am fairly sure that I use #18 needle for V92 thread. When going to heaver thread, needle size changes and also tensions.

I have a 1541 using v92 thread with a #18 needle so you should be fine there. If you just going through a single layer it would be to light for that machine like Lee suggested.

For the bottom bobbin tension shoot for what is shown in the video…. Once you the bottom close you can pretty much ignore it and just use the top tension to correct …….assuming your timing is on

Thank you for the answers!
I have sawn 2 layers together the whole time of course. The total thickness was 2.2 mm.
I will keep on trying and come back with the solution once I've found the cause!