X/0 vs. Denier

I'm trying to make sense of the X/0 sizing for thread versus the denier sizing method. I have Uni's Big B thread, which I believe is a 40 denier, and I'm wondering how it compares to 6/0 Uni. It looks like it's about twice the size of 6/0 and actually makes really strong furled leaders. Can anyone help me get my head around this? Simple minds want to know.

Brought to you through the magic of the internet

http://www.flytyingworld.com/classro...0-Threads.html

Or

http://www.flyfishusa.com/fly-tying/thread.htm

Or

http://mvff.tripod.com/Reference/Denier.pdf. (i printed this one)

Hope it helps

This may help:

http://mvff.tripod.com/Reference/Denier.pdf

Regards,
Scott

ooops, looks like maodiver beat me to the punch

Suspect you have the denier measurement wrong fro the Big Fly thread. My searches indicate 400 denier, not 40. According to the Uni-thread site (which is also wrong) it is 4X stronger and 4X thicker than 6/0. Perhaps that's the source of the confusion? Good luck figuring out proportions. Empirical testing (aka just try it) is probably your best bet.

Uni Big B is 440 denier not 40. Uni 6/0 is 135 denier. See the chart in this Chris Helms article. http://www.swtu.org/pdfs/fly_tying/Threads.pdf

Thanks you guys. My mind can rest now. I have a few spools of Big Fly and I don't like it for anything other than furled leaders.