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).
Letter detailing costs and specifications for machine tool equipment for rifling and boring a 40mm barrel.
| Identifier | ExFiles\Box 170\4\ img020 | |
| Date | 17th July 1940 | |
| July 17, 1940 Mr. Olley: Regarding Robotham cable July 5, which reads as follows: "Please investigate delivery machine tool equipment for rifling and boring barrel 40 millimetre bore 80 inches long." Pratt Whitney have replied as follows: - Specify their # 1-1/2 x 105" machine. - Drilling Operation 2 spindle machine costs $13,900 and drills at rate approximately 1" per minute. - Reaming Operation 2 spindle machine costs $13,900 and ream at rate approximately 2" per minute. - Rifling Operation 2 spindle machine costs $17,315 requiring approximately 6-1/2 hours per barrel. - Chambering Operation 8 spindle machine no cost available as yet. The machine rates arrived at are based on adverse machining conditions - lesser machine times are contingent upon more favorable machineability of materials. NOTE: The above data includes drilling, reaming, rifling, and chambering equipment - I have requested Pratt & Whitney to furnish complete operations, assuming that they are to work from solid material. More definite information cannot be forthcoming. For instance, production required should have been specified. At present an October delivery is forthcoming contingent upon government priorities. In this case, may I suggest that you urge Mr. Baker to endeavor apply government priority ratings. This has been done on several export orders, so far to my knowledge. I have checked Natco, Excello and W.F. & John Barnes, all to no avail. I am now checking LeBlond as a last possible source. - Alternative Pratt & Whitney. L.G. Ringholz | ||