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What is Mil-Spec Sewing Thread

High Strength Sewing Thread Manufacturer

HongFeng sewing threads are able to assist mil-spec (military standard or military specifications) sewing thread needs. These sewing threads are used in various product threads such as boots, parachute harnesses, molle packs, apparel, and many other items for the military. Although the mil-spec sewing thread isn’t used only for government uses, mil-spec sewing thread is designed to meet specific criteria, applications include – Battle Dress Uniforms, Parachute Harnesses, Postal Uniforms, Molle packs, Boots, and various Military accessories.

Here’s a summary of MIL-DTL-32072 the United States Department of Defense product standard for the multifilament polyester thread to be used in machine sewing. The standard outlines minimum product physical specifications and is divided into several sections in the 17-page standard.

Thread Types

A polyester thread is designated as one of five types by MIL-DTL-32072. These types describe the basic construction of the thread, or how the thread is assembled or manufactured:

  • Type I – Twisted soft multiple cords – twisted, multiple cord (ply) construction. This is called yarn or two-step twisted yarn, not bonded, with a soft finish.
  • Type II – Twisted bonded multiple cords – the same construction as type I, except that the type II thread is bonded.
  • Type III – Bonded mono cord – a single-ply, mono cord construction with a single twist of no more than five turns per inch (tpi). Type III thread is bonded to form a smooth even mono cord.
  • Type IV – Soft air entangled – one or more yarns that are air entangled together by the manufacturing process to form a single-ply thread with a final twist of no more than 10 TPI, not bonded with a soft finish.
  • Type V – Bonded air entangled – the same construction as type IV except that the type V thread is bonded.


There are two classes and three subclasses listed as part of the standard that addresses other properties of the thread – Classes describe elongation or shrinkage and Subclasses address thread finish:

  • Class 1 – Normal Elongation – this is a maximum elongation percentage of 26 percent at the break.
  • Class 3 – Heat Stable – low shrinkage – this is an elongation at the break between 15 to 35 percent.
  • Subclasses:
  • Subclass A – General Purpose
  • Subclass B – Non-wicking Finish
  • Subclass C – No Finish

Works Cited: What is Mil Spec Thread: MIL-DTL-32072 (formerly V-T-285-F)