Draft Calculator
Draft is how many times the material is thinned: a 0.12 hank sliver drafted to 1 hank roving has a draft of 8.33333.
8.33333333333333
Full answer, then cut to fewer decimals (not rounded):
- 8.33333333333333
- 8.3333333333333
- 8.333333333333
- 8.33333333333
- 8.3333333333
- 8.333333333
- 8.33333333
- 8.3333333
- 8.333333
- 8.33333
- 8.3333
- 8.333
- 8.33
- 8.3
- Doublings
- 1
Step-by-step solution
- Draft = (delivered count × doublings) ÷ feed count
- = 1 × 1 ÷ 0.12 = 8.33333
Draft Formula
Draft = N_out × doublings ÷ N_in
indirect counts; mechanical draft = delivery ÷ feed surface speed; actual = mechanical ÷ (1 − waste)
Worked Example
A 0.12 hank sliver drafted to a 1 hank roving with no doubling:
- Draft = (delivered count × doublings) ÷ feed count
- = 1 × 1 ÷ 0.12 = 8.33333
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TM = TPI ÷ √Ne
αm = TPM ÷ √Nm, αtex = TPM × √tex; 1 TPI = 39.37 TPM
Example: A 20s Ne cotton yarn with 16.1 turns per inch: Twist multiplier TM = 3.6001.
-
Spinning Production Calculator
kg/h = speed (m/min) × 60 × ktex × η ÷ 1000
ring frame: delivery speed = spindle rpm ÷ TPM
Example: A card delivering 5 ktex sliver at 150 m/min and 90 % efficiency: Production = 40.5 kg/h.
-
Yarn Diameter Calculator
d = √[4 × tex × 10⁻⁶ ÷ (π ρ φ)]
ρ fibre density, φ packing fraction; Peirce cotton d (in) = 1/(28√Ne)
Example: A 20s cotton yarn (ρ = 1.52 g/cm³, φ = 0.6): Yarn diameter d = 0.203034 mm.
Frequently asked questions
What is the difference between actual and mechanical draft?
Mechanical draft is the ratio of roller surface speeds; actual draft is the ratio of linear densities, higher when waste is removed: actual = mechanical ÷ (1 − waste).
How do doublings affect draft?
Feeding n slivers together multiplies the input linear density by n, so the draft needed for the same output is n times larger.
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Draft Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/draft-calculator/
IEEE
Scientific Converters, "Draft Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/draft-calculator/