Thread size for sewing machines, can someone explain the numbers?

[Wizcrafts]

4 hours ago, DrmCa said:

How would a sewing machine operator in a factory know left twist thread from right twist thread when having to thread their double-needle machine? Labels have a tendency to fall off cones, after a while, and not everyone's vision is good enough to see the twist, especially in low light that some factories have.

Sewers in factories may just sew and somebody else may change spools of thread. Just saying. I always change my own when I sew for others, but, I sometimes change thread for my replacements and oil the machines when they are done.

[JLSleather]

Just when you thought it was safe to go back in the water.....
 

I have seen the "same size" thread from different manufacturers which were NOT the same size.  I mean, 227 from Co.A and 277 from CoB were NOT the same size... VISIBLY different, no micrometer needed.

 

[Constabulary]

Industrial standard thread size is usually not calculated by diameter it is calculated by weight per 1000 meters or similar. The diameter is an approx guesstimate - in most cases to help (or confuse) the end consumer. Linen thread is another story.

Have fun with this:

http://www.cleavebooks.co.uk/scol/ccdentex.htm

This table may be useful too.

Edited January 25, 2022 by Constabulary

[kgg]

8 hours ago, Constabulary said:

Have fun with this

Thread information can really send you down a never ending rabbit hole. Particularly when you compare single to two or three core.

kgg

[Gymnast]

On 1/26/2022 at 6:17 AM, kgg said:

Thread information can really send you down a never ending rabbit hole. Particularly when you compare single to two or three core.

kgg

This is from a manual of a Household Janome HD9 straight stitch sewing machine. I think it is a relative new type of sewing machine - perhaps 10 years old, but is still being sold. The only specifications I can find regarding how heavy thread or fabrics it may be able to handle is this table on page 32. Do you know what kind of threads these are?

[jcuk]

On 1/25/2022 at 8:15 PM, JLSleather said:

Just when you thought it was safe to go back in the water.....
 

I have seen the "same size" thread from different manufacturers which were NOT the same size.  I mean, 227 from Co.A and 277 from CoB were NOT the same size... VISIBLY different, no micrometer needed.

 

I have noticed this with different brands hand stitching thread too. Some of the threads look like they are weight down from what they should be.

Hope this helps

JCUK

[kgg]

5 hours ago, Gymnast said:

Do you know what kind of threads these are?

I think they are using the " Gunze Count standard " where the larger the number the thinner the thread for a given number of ply. Those sizes would be typically seen at your local fabric store in those small domestic size spools. The number is referring to the weight of the thread but not the number of cords (piles) that make up the thread. Where a #30 2 ply isn't the same size as #30 3 ply but is labeled as #30 weight. Confusing??? From the needle size the machine should be able to handle correctly thread up to V69 (T70, Tkt 40).

kgg

[Gymnast]

On 1/25/2022 at 8:36 AM, Wizcrafts said:

Yes, you are correct. It is only on machines where one shuttle turns clockwise and the other counterclockwise that different thread twists are advised.

The Landis 12 series sole stitching machines all require right twist (waxed linen) thread. It's likely that other old shoe sewing machines have that right, or S twist requirement.

I think it needs to be the manufacturer of the machine, that make the S-twist requirement. I just noticed, that many normal machines using normal Z-twist thread got different direction of the hook relative to the needle. In the previously shown video, you got the hook approaching from right from needle perspective. I have looked at some of my machines and some other videos, and the direction of the hook vary:

Hook approach from right:
Singer 66, Singer 201, Pfaff 130, Pfaff 138, Singer 501a, Consew 206rb, Pfaff 545

Hook approach from left:
CB4500, Machines with CB-hook, Machines with long shuttle, Husqvarna Viking 6010 (and similar with double rotating vertical hook).  

So it seems that this decision for the designer of the sewing machines was not influenced by the preferred use of Z-twisted thread. 

I have tried to press a needle with thread through some vinyl and retract it a bit to simulate the loop forming. I think there is a tendency, that the thread gets locally twisted near the needle due to the friction against fabric, and therefore I see a tendency that the thread loop goes a bit to the right as seen in this picture, but you also have a significant variation on that every time you try:


 When you look this photo, you may prefer to have the hook from right. But I tend to believe, that this matter has little significance.