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).
Ball bearing fits and tolerances for 25 HP & Peregrine gearboxes.
| Identifier | ExFiles\Box 2\4\ B002_X 127 128-page21 | |
| Date | 12th September 1932 | |
| Copy Roy.{Sir Henry Royce}(WW) c. Sr. c. Nor. c. Br.{T. E. Bellringer - Repair Manager} c. E.{Mr Elliott - Chief Engineer} c. H.{Arthur M. Hanbury - Head Complaints} c. DA.{Bernard Day - Chassis Design} c. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} c. BRC. X128 SY.8/G.12.9.32. X 5310 BALL BEARING FITS. 25 HP. & PEREGRINE GEARBOXES. ---------------------------------------------------- Referring to HDY.{William Hardy}1/M.6.9.32. the fine limit on the shaft diameter where the ball bearing is seated is not due to having to pass the bearing over a similar size spigot to reach its final position, it is the result of many discussions with the Works to :- a/- Ensure a reasonable positive interference type of fit. b/- Avoid as far as possible the upper limit, making the interference fit too great. Hoffmans limits for bearing and shaft are :- a/- Bore of bearing where bore is 'b' b + .0002 - .0003 b/- Shaft diameter where diameter is 'd' d + .0002 + .0007 These limits give a maximum interference fit of .001 which is much too high to permit the parts to be assembled as has to be done in our case with the parts dropped in from above and the shaft threaded through the gears and bearings. On the other hand it is essential that we have | ||