The Upholstery Forum

First go at making a motorbike seat.
Intending on using some .7mm vinyl, I have already bought it.
I also got some black thread, the label says 20S/3.
I was going to do the top of the seat with parallel rows of stitches, and looking at upholstery
the thread used looks thicker than the stuff I bought.
What should I be using?
sewing machine is an old Jones.

You could use 92. I use 138 for motorcycle seats and auto seats.

I use 92 for the main seams and 207 for decorative stitching.

92, 138, 207.
Which is the thickest?
From my 20 not being very thick I am guessing 207 doubles as tow rope.

Not sure what your 20 is. There are different scales used for domestic vs industrial size threads so just comparing numbers isn't really helpful.

I found this page which may help shed some light....

https://www.superiorthreads.com/educati ... a%2030%2F2).

Also, this page gives a good overview of what the different industrial class threads are and how the compare to each other.

https://www.sailrite.com/Selecting-the- ... G7f1V2Kasg

As you've thought, as the numbers go higher for commercial sizes, the thread gets thicker. 207 is thicker then 138 which is thicker then 92.

Can you post a pic of the label on your thread? It should help determine what you have and if it's usable for your project. Also, if you know the make and model of your machine add that to your next post.

Jones Z-620. My mother bought it in 1963. With it is a pack of 90,100&110 needles and on my last ali-express order I got some 120 needles.
The roll of thread I bought has 203 on the packaging label, and 20S/3 on the cellophane wrapper, it had 20S/3 on the website and it said heavy duty?

I have a roll of red thread that I bought for dressing crossbow stings, it's pretty fat compared to the stuff I found with the sewing machine. The labels fell off the roll about 50 years ago;-)

I was given a pile of leather from an old sofa. I just found a thick exposed seam and pulled the thread out, it has thick thread for the exposed bit and less thick on the underneath. The thick thread looks much like my string dressing stuff.

I was able to thread the thick stuff though the 120 needles I bought.

can you post a link to your thread?

The only thing I'm finding is it my be a 20 s 3 which would be comparable to to tex 20.

If that's the case, it's a far thinner thread then most of us use for upholstery.

As for your machine, I'm not finding much on it either. Other then it appears to be a "medium" duty domestic.

integerspin wrote: ↑Fri Jan 10, 2025 5:56 pm Jones Z-620. My mother bought it in 1963. With it is a pack of 90,100&110 needles and on my last ali-express order I got some 120 needles.
The roll of thread I bought has 203 on the packaging label, and 20S/3 on the cellophane wrapper, it had 20S/3 on the website and it said heavy duty?

I have a roll of red thread that I bought for dressing crossbow stings, it's pretty fat compared to the stuff I found with the sewing machine. The labels fell off the roll about 50 years ago;-)

I was given a pile of leather from an old sofa. I just found a thick exposed seam and pulled the thread out, it has thick thread for the exposed bit and less thick on the underneath. The thick thread looks much like my string dressing stuff.

I was able to thread the thick stuff though the 120 needles I bought.

Your 1963 Jones Z-620 is holding up well!