I'll try to answer Ed, John M, and John R, in this post. Ed, most errors in the Helm-Merg chart arise from the measurement method, e.g., all flat thread diameter measurements are meaningless, but a few of other types follow. Nonetheless, although I was hard on Helm-Merg in yesterday's post, in fairness they did say that their methods weren't "scientific." 1. Danville 17/0 Spiderweb is listed as having a diameter of 2.0 (thousands), the same as UNI 8/0. Anyone who has or has seen Spiderweb knows this is nonsense. In fact, in the text they give Danville 17/0 as 30 denier. 2. UNI 6/0 is listed as a "flat" thread, it's not, it's the same type as UNI 8/0 - i.e. a simple twist.
John M 1. Yes, denier (decitex is another similar measurement used in the textile industry) is analogous to line weight. Denier wasn't used by spoolers (remember that tying thread isn't manufactured by companies like UNI-Products, it is respooled - sometimes with additional treatments like waxing - from huge bulk spools from the textile industry) because, with a limited number of suppliers, the old x/0 system was familiar to fly tiers and at least gave relative sizes. Not until some companies began exploiting the x/0 system, hoping to seduce fly tiers with misrepresentations, did the comfortable situation collapse. I was a little surprised that no one asked about the origins of the x/0 system. In fact, no one knows (I spent 100+ hours of research into the topic). Best guess was that it originated with catgut suture sizes (I even had medical historians looking into 19th century medical texts) but there is still no proof of this. Whatever, there is absolutely NO STANDARD, or even a table in the literature, that gives an x/0 - diameter relationship. That's why some companies felt justified in putting on whatever number they felt would increase sales. I would say that the reason not all companies are doing this is simply a matter of consumer education (and perhaps space on the label). Of course some wouldn't want you to know the denier of their thread. In fact, in a follow-up article to the Helm-Merg article/table, Bill Merg championed this (unfortunately he also recommended other info that simply won't fit on a spool label). John R 1. Even given my reservations about the test methods, here is what the chart showed: UNI 8/0: Breaking strength - 15 oz Diameter 2.0 (000's) Benecchi 12/0: Breaking strength - 15 oz Diameter 1.9 (000's) Given the problems with the test method for diameter (the strength test was better, but still suspect in the last digit), those two diameters are identical. I ran multiple diameter tests (a different and more reliable method for simple twist threads) on UNI 8/0, Benecchi 12/0, and Griffith 14/0 threads - even though I already knew they were identical - and the results were as already stated. For those who have read this far, here are a few thread tips: 1. Waxed threads aren't waxed for dubbing as many think. Waxing keeps the thread from fraying (especially beneficial for folks like me with rough fingers) and helps it bite into some materials - I tie mostly with waxed thread. You must add a sticky wax if you want dubbing assistance. 2. Be suspicious of high-strengh/low-diameter claims unless it is a completely different material like GSP. Nylon threads are generally weaker than polyester threads for the same denier. 3. If you need a strong, expensive, thread like a GSP thread (hard on scissors!) to bind down large amounts of incompressible synthetics, remember that you can use a much less expensive polyester thread to build a head. I could go on but have run out of time. Cheers, Paul -- Paul Marriner Outdoor Writing & Photography. Member OWAA & OWC. Author of Atlantic Salmon, Ausable River Journal, Miramichi River Journal, and Modern Atlantic Salmon Flies.
