There was a recent post by someone looking for a 30wt thread and responses that we never heard of it, or that it seemed like an awfully thick thread for the application she was going to use it for.

Well, I actually found two spools of 30wt 2 ply in my thread box today when I was looking for the right color to quilt with. Note: I'm not "married" to any thread manufacturer or weight or anything - I have a smorgasbord of thread in my box.

I pulled both of these 30wt spools - both are made by Sulky. One just says 30wt mercerized cotton, the other says 30wt blendable long stiple cotton. Both are two ply.

They feel and look so DIFFERENT in weight and thickness.

I've also noticed this with 50wt from different manufacturers - Gutterman is much thinner than Essential from CT - both are 2 ply. I've noticed differences in others as well.

So ... can I REALLY trust the weight of the thread? Apparently not.

i agree with you. i use many thread brands, many different weights, and many different fibers and when you compare apples to apples they do not look the same in diameter even though they are cotton 50 weight.

I think that I read somewhere that the European brands of threads have a different twist than the other brands....Could this be part of the reason for the different weights?

This is some information that I found when I googles sewing thread.

http://www.ylicorp.com/pdf/tot-brochure.pdf

TERRIFIC! I have been wondering how the Tex system relates to the old style thread weights and this explains how a 50wt thread can be so much different in diameter than another 50wt. Thank you! :)

I don't pay that much attention to the weight on the labels as much as looking at the thread itself for this same reason.

I noticed the difference in the diameter/size of 40 wt cotton, poly, rayon, really varies throughout the different brands in my stash.
I haven't noticed it so much in the 50 wt because I bought so much and such large spools of the same brand that I haven't had to replace any of it yet LOL :D:D:D