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Industrial Sewing Thread Diameter and Gauge

In sewing applications, the needle size required is based on the thickness of the sewing thread selected.   Many customers know what size thread they want to use, but may not know which needle size to use. 

Thread SizeGovernment Letter SizeGauge (Thickness)Minimum Recommended Needle Size

3 Common Thread Sizing Systems

high bulk textured polyester thread
high bulk textured polyester thread

Tex (T):

Tex is the most consistent of the measuring methods. It uses a fixed length to measure the weight of a thread. Tex is the weight (in grams) of 1,000 meters of thread. Or, in other words, 1,000 meters of thread that weighs 1 gm. = 1 Tex. The higher the tex, the thicker the thread.

Denier Count (Td or d):

Denier also measures thread at a fixed length. It is the weight (in grams) of 9,000 meters (or 9 km) of thread. You might recognize the term from descriptions of nylon fabrics, which are often classified by the denier of the threads from which they are woven.

Commercial Sizes (V):

Commercial sizes are used for heavy-duty threads for sewing heavy upholstery, canvas, or webbing. Commercial sizes are set sizes of 30, 46, 69, 92, 138, 207, 277, 346, 415, and 554. They are the thread’s denier divided by 10. Commercial sizes are standard for marine-grade thread (you’ll see commercial sizes on the Sailrite website for our outdoor thread).

6 Quick Tips About Thread Size

  • V-69 is the heaviest commercial size recommended for home sewing machines.
  • Heavier threads make your stitching more visible.
  • The thread size measures the thread’s thickness. If another weight is given for thread (like ounces), it refers to the amount of thread on the spool.
  • Thread tends to get stronger as it gets heavier.
  • The tension on your sewing machine will need adjusting when you switch thread weights.
  • Try to use a needle where the eye is 40% larger than the thickness of the thread.

Works Cited: Understanding Thread Sizing