From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Table detailing the specifications for different types of worms and nuts.
| Identifier | ExFiles\Box 67\4\ scan0376 | |
| Date | 3rd October 1927 | |
| PARTICULARS OF WORMS AND NUTS 3/10/27. LEAD: .940 .720 .900 Piece nos. F.73600/1. F.75596/7. Pitch Dia. 1.400" 1.800" 2.180 Outer Dia. 1.490 1.890 2.320 Inner Dia. 1.250 1.630 1.930 Angle of thread (θ) 12° 4' 7° 15' 7° 35' Proj. area sq. ins. 5.4 7.66 12.3 Pressure ∠ 14 1/2 ° 14 1/2 ° Leverage in Bend. Levers 4.790 6.290 5.000 No. of starts. 4. 3. 3. | ||