"riverman" wrote in message
ups.com...

Can anyone give me a summary of the relationship between the X system
of tippets, and the breaking strength?

The X system described tippet thickness when the
material was silkworm glands, drawn out into threads
through a series of dies. Thus the 4X die produced
tippet lengths about 0.007 inches diam. This much
silkworm material had a breaking strength of a few
pounds (varying with source quality, dampness,
abrasion etc.)

Nylon tippets were usually measured in thousandths
of an inch, and strength varied with thickness: no
problem except for quality of the source. Trout anglers
point out presentation the wear on the knot are of
more practical importance than notional strength.

But flurocarbon material is stronger for unit diameter
than nylon, and some makers (e.g. Pezon & Miichel)
always advertised special nylon formulae for tippets,
supposedly stronger.

My Mongolia connection
recommends using a 10-12 pound tippet, but I'm not at all sure what
size that is.

This is normal for big fish that are not leader shy. Quebec
salmon fishermen go by breaking strain rather than tippet
diameter, in the range 20 lb. to 10 lb.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)