Just curious: What is the equivalent Denier of my big stash of standard Danville 6/0 waxed Flymaster thread? I think Danville is one of the few that don’t print that info or the thread color ID on each spool. They have so many shades of brown and tan that the detailed ID is really needed to reorder. Thanks
IIRC, 6/o is roughly equivalent to 140 Denier
Must have been a while since you bought thread, because Danville has been printing the denier on their spools for a while. According to the web site, the 6/0 is 70 denier. You can also always look on the web site for colors: http://www.danvillechenille.com/flymstr.htm.
and the uni site says their 6/0 is 135 denier…that is Uni-Tread 6/0 = 135 denier
please bookmark
http://flyfisherman.com/ftb/ssthread/index2.html
I had one of the links and saved the other two. 
I just took delivery of 4 spools of GSP 100 and 4 of GSP 200, will have to scour the Waspi site some more for break strength.
Please don’t take it the wrong way guys but I finally phoned Danville and their 6/0 is 70 Denier. I didn’t ask about any other brands. Thanks for the interest anyway.
3/O, 6/0, 8/0, 10/O; have no bases for comparison, for comparison between manufacturers.
Denier is the weight of the thread in grams, for 9000 meters of the thread.
That still does not give you it’s tension breaking strength, or tread diameter.
General Rule: Is that 3/0 is 210 denier, 6/0 is 140 denier, and 8/0 is 70 denier, unless the manufacturer says otherwise.
~Parnelli
I wrote an article on thread, many years ago for FAOL, on thread…interesting read for the background of what goes into making of thread, and the different processes it goes through…
Parnelli…I asked this on the other thread relative to your Big Leader Formula…if denier is related to weight does that effect the formula?
For the latest in thread Brands,Aught size,Material,Denier, Breaking Strength,and Thickness go to Chris Helms catalog page 17
www.whitetailtieing.com
Also a article on"Using Denier to Standardize Fly Tying Thread"
Parnelli for your chart Benecchi 8/0 150 denier–10/0 120–12/0 70
BILL :tieone:
Hi guys,
Unfortuneately there is a lot of difference of sizing from one manufacturer to another just like some hook manufacturers but Steve is right about the denier per 9000 meters of product. FYI, just got my first order of the fall season from Danville and the spools are marked:
70 (old 6/0)
140 (old 3/0)
210 (old size A or single strand floss)
By the way, Gretchen and I always use 210 denier (size A) unwaxed for our single strand floss because it lays down such a nice smooth body straight out of the bobbin. We tie all of our size #14 & larger Humpies with it then switch to 140 or 70 for the smaller sizes. Take care & …
Tight Lines - Gretchen & Al Beatty
www.btsflyfishing.com
that link didn’t work for me
Thank you for posting these. That was very helpful for me. Now I know why I prefer flat waxed or fly master plus…because the breaking strength is much better…I got the regular flymasters, and I just kept breaking it…but it is good for smaller heads though to make them look smoother 
heres the catalog from chris helm
This thread has me thinking of thread (OK it didn’t start out as a joke), but I pulled out my own tying supplies and it really is amazing what one accumulates. I have benecchi, Danville, Gudebrod, Orvis, [FONT=Arial][SIZE=1][/SIZE][/FONT]Uni and Ultra (UTC) as brands. Just took delivery of 8 spools of GSP this week to play wth.
The article in the Chris Helms catalog was a good short piece and the article that was referenced earlier in the thread on the Fly Fisherman web site, I have in my favorites. If I was a new guy, just starting out, I would see what was available locally. This would allow me to go to my local shop and buy a couple of spools that match everything else that I have. Then you won’t end up with 6 different brands and your range of threads won’t overlap so much or be so redundant.
For me I would probably select Waspi UTC product. If I tied smaller patterns I would start with 70 and 140. If I fished a little larger patterns maybe 140 and 210. I would keep it much simpler than my current condition.
That link did work for me, and it was an interesting read. Thank you. I prefer threads such as flat waxed nylon, or Flymasters Plus. I guess you can say I am a bit of a heavy handed tyer. I tend to break lighter threads, and that is very frustrating. So I tend to stick with heavier threads. Now if I am making a small fly, I can go with a lighter thread.
Clay I know what you mean. I just realized I have more spools of thread on my fly tying table then my wife has in her sewing room! And I’m sure I need a few more…