Thread size question

[Snakeoil]

I know that thread "size" is really weight thing. I've spent more time than I care to admit searching the web for thread dimensions that do not seem to exist.

So, here's my question. I have some unmarked large industrial size spools of thread. I'd like to be able to measure the diameter to get an idea of the actual thread size. Is there a general rule of thumb for doing this. And yes, I've read the thread and needles and the thread sizing trick threads (sounds redundant, doesn't it?) that area pinned above. It's not critical, but I'd like an idea of the grade of thread I have which is unidentified.

I have measured thread that is marked and compared it. So I have an idea. But looking for an experienced viewpoint on this.

Thanks,

Rob

[fredk]

Simplest way; get a ruler  in your preferred measure, eg mm or inch. Start on the '0' line and wrap thread around the ruler, each turn tight up against the last. Keep going for a few inches or centimetres. Count how many threads there are an divide into the measure eg, if you have 80 turns over 2cm /20mm = each thread is 0.25mm

[Wizcrafts]

You can find the diameter of commonly used bonded thread in this needle and thread chart.

[Snakeoil]

Thanks Wiz. I looked all over the web for a chart like that.

regards,,

Rob