String Thickness Estimator

Enter your string material, strand count, and serving. The estimator calculates finished diameter — bare bundle and fully served. Use the reverse lookup to find the strand count that hits a target diameter.

All values are estimates. Actual results vary with serving tension, burnishing, and settling time. Use these numbers as a starting point and verify with calipers on your finished string.

String

Material

Strand count

Serving

Serving material

Bare bundle

—

Burnished & settled estimate

Fully served

—

Center served diameter

Serving adds

—

Total added to diameter

Reverse lookup — find strand count for a target diameter

Target served diameter (in)

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Strand count comparison — current material & serving

Strands	Bundle ⌀	Served ⌀	Nock fit

How the formula works

Bundle diameter formula: D = c × N^0.309, where N is strand count and c is a material constant. This is a power law fit rather than a theoretical packing model. Textbook circle-packing theory predicts an exponent of 0.5 (√N) — the geometry of dry, unbonded cylinders packed at random. Real burnished strings pack significantly tighter, producing an exponent near 0.31.

The reason is wax displacement. BCY 452X and similar materials are wax-based. During burnishing, heat and pressure work the wax into the interstitial voids between strands. Wax displaces the air gaps that dry packing theory assumes are present. The strands seat closer together than geometry alone predicts, and continued burnishing progressively fills more of the void — which is why a burnished and settled string is the correct reference state. All values shown are estimates; treat them as a starting point and verify with calipers.