UTC Ultra Thread 140D is a strong, ultra-flat fly tying thread designed for medium to large fly patterns that need durability, smooth coverage, and clean material control. Made from unbonded multifilament nylon, this 140 denier thread lays exceptionally flat on the hook shank, helping reduce bulk while creating smooth underbodies, clean heads, and even thread bases.
With a break strength of roughly 2 lbs and approximately 25% to 30% stretch, UTC Ultra Thread 140D gives fly tyers the strength needed to secure larger materials without constantly worrying about break-offs. It is an excellent choice for streamers, hoppers, woolly buggers, mice, saltwater flies, bass bugs, articulated patterns, and larger trout flies.
UTC Ultra Thread 140D is a great balance of strength, control, and smooth tying performance. It is stronger than 70 denier thread but still lays flat enough to avoid bulky heads and uneven bodies. We especially like it for bigger flies where you need more holding power, but still want a clean, professional finish.
Its flat ribbon-like profile also makes it excellent for split-thread dubbing techniques, smooth underbodies, and tying flies where neat proportions matter.
UTC Ultra Thread 140D is ideal for tying:
For the flattest wraps, spin your bobbin counter-clockwise to untwist the thread and help it lay smooth like a ribbon. This is especially useful when building underbodies, tapered thread bases, or clean fly heads.
When you need more bite and strength, spin the bobbin clockwise to cord the thread into a tighter, rounder profile. This helps when locking down slippery synthetics, dumbbell eyes, bucktail, or stinger wire loops.
Because UTC Ultra Thread 140D is a floss-like multifilament nylon, rough fingertips can sometimes snag the fibers. Keeping your hands smooth will help prevent fraying and give you cleaner wraps.
