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).
Conversion table for various tapers, providing corresponding angles and dimensions.
| Identifier | ExFiles\Box 33\1\ Scan012 | |
| Date | 24th January 1920 | |
| X.1448 24.1.20 Taper Angle A (exact to nearest second) Dimensions X. (Exact to five significant figures) 1 in 5 11° 25' 16" .99010 1 in 6 9° 31' 38" .82759 1 in 8 7° 9' 10" .62257 1 in 10 5° 43' 29" .49875 1 in 20 2° 51' 51" .24984 1 in 48 1° 11' 37" .10416 1 in 200 0° 17' 11" .02500 Ck.{Mr Clark} RR 1358 T (S.F. 816 8849) C 2400 | ||