Fundamental Linen Lea Conversions and Metric Yarn Calculations
Linen Lea converts to Metric count via NeL multiplied by 0.604772, while direct Tex equals 1653.52 divided by NeL, adjusted for 12% moisture regain.
Lea Strength Index
Bundle Strength
Yarn strength metrics represent the collective resistance of a group of threads wrapped into a loop when subjected to a breaking force. Textile spinners determine the lea strength index to judge the weaving performance of flax yarn batches. This index is the standard metric used in the linen industry to compare yarn lots of different counts.
The final test results are entered into the mill laboratory register for quality audit purposes.
Measurement Method
The test procedure requires winding a yarn loop of one hundred and twenty yards on a warp reel to form a skein or lea. Technicians place this yarn loop on the two spools of a lea tester and separate them at a uniform speed until the bundle breaks. In Chinese mills, the tester measures the breaking load in pounds, and this value is multiplied by the yarn count to find the index.
This double measurement combines linear density and tensile strength into a single value. This allows the laboratory to evaluate yarn quality without running dozens of individual single thread break tests.
Production Setting
Loom warp preparation relies on this index to prevent excessive breakages on the factory floor during the shedding process. When the lea strength index is low, the weaver must decrease the loom speed to protect the yarn from high tension peaks. Spinners use these results to adjust the twisting parameters in the wet spinning frame to optimize strength.