| Description | Date | Identifier | |
| Letter from The Rover Company Ltd. discussing production wages to material percentages for a 12-HP model. | 23th Nov 1937 | Box 127 \ 3 scan0203 | |
| Parts list for 12 HP models supplied as complete assemblies or units. | 23th Nov 1937 | Box 127 \ 3 scan0204 | |
| Parts list showing quantity per set, part number, and description for various vehicle components. | 6th Jan 1938 | Box 127 \ 3 scan0205 | |
| Letter from S.B. Wilks of The Rover Company Ltd. regarding a missed phone call. | 6th Jan 1938 | Box 127 \ 3 scan0206 | |
| Letter to Maurice Wilks at The Rover Company regarding a new door lock and stellited silchrome valves. | 27th Jan 1938 | Box 127 \ 3 scan0207 | |
| Letter to Maurice Wilks of The Rover Motor Co. Ltd. regarding a drawing of an L. section ring. | 23th Feb 1938 | Box 127 \ 3 scan0208 | |
| Letter to M. Wilks of The Rover Company regarding materials and angles for synchromesh cones. | 23th Mar 1938 | Box 127 \ 3 scan0209 | |
| Letter from The Rover Company asking for details on the chromium plating process used on steel to avoid rust. | 31th Mar 1938 | Box 127 \ 3 scan0210 | |
| Letter to The Rover Co. Ltd. detailing standard practices for nickel and chromium plating to prevent rust. | 6th Apr 1938 | Box 127 \ 3 scan0211 | |
| Letter from The Rover Company Ltd. thanking for particulars on chromium plating steel. | 7th Apr 1938 | Box 127 \ 3 scan0212 | |
| Letter from The Rover Company Ltd. requesting samples of chromium-plated steel parts for a salt spray test. | 26th Apr 1938 | Box 127 \ 3 scan0213 | |
| Letter to The Rover Co. Ltd. regarding the plating and testing of a Bentley car's wheel retaining nut. | 27th Apr 1938 | Box 127 \ 3 scan0214 | |
| The dispatch of a Bentley Road Wheel nut to The Rover Co. Coventry. | 27th Apr 1938 | Box 127 \ 3 scan0215 | |
| The dispatch of one Bentley Road Wheel Nut to The Rover Co. Ltd. | 29th Apr 1938 | Box 127 \ 3 scan0216 | |
| Letter from The Rover Company Ltd acknowledging receipt of a Bentley Wheel Nut. | 2nd May 1938 | Box 127 \ 3 scan0217 | |
| Letter to Rover regarding fuel consumption and rear tyre mileage on the 12 HP model. | 14th May 1938 | Box 127 \ 3 scan0218 | |
| Letter from The Rover Company Ltd arranging a lunch meeting and discussing tyre mileage. | 16th May 1938 | Box 127 \ 3 scan0219 | |
| Letter from The Rover Company Ltd. to W.A. Robotham regarding rescheduling a visit due to a misunderstanding and illness. | 17th May 1938 | Box 127 \ 3 scan0220 | |
| Letter to M.C. Wilks of The Rover Company Ltd. correcting a meeting date and suggesting alternatives. | 17th May 1938 | Box 127 \ 3 scan0221 | |
| Letter from The Rover Company Ltd to W.A. Robotham apologising for a mistake over dates and confirming a meeting. | 21th May 1938 | Box 127 \ 3 scan0222 | |
| Letter to Capt. S.B. Wilks of The Rover Company Ltd., confirming a meeting arrangement. | 23th May 1938 | Box 127 \ 3 scan0223 | |
| Private memo discussing the high cost of forgings and a proposal to establish a new forging company with modern equipment. | 25th May 1938 | Box 127 \ 3 scan0224 | |
| Letter to Capt. S.B. Wilks of The Rover Company Ltd. regarding a meeting and a future visit. | 25th May 1938 | Box 127 \ 3 scan0225 | |
| Letter to The Rover Company Ltd. regarding a synchromesh cone assembly. | 26th May 1938 | Box 127 \ 3 scan0226 | |
| Letter from The Rover Company Ltd. discussing gearbox weight, materials, and design. | 26th May 1938 | Box 127 \ 3 scan0227 | |
| Letter from S.B. Wilks of The Rover Company Ltd. to G.H. Grylls regarding a synchromesh cone. | 27th May 1938 | Box 127 \ 3 scan0228 | |
| Cover memo for an attached letter from Wilks concerning the gearbox. | 28th May 1938 | Box 127 \ 3 scan0229 | |
| Letter from The Rover Company Ltd. to W.A. Robotham regarding the arrangement of a works visit. | 30th May 1938 | Box 127 \ 3 scan0230 | |
| Letter from S.B. Wilks of The Rover Company Ltd. to W.A. Robotham of Rolls-Royce arranging a meeting. | 10th Jun 1938 | Box 127 \ 3 scan0231 | |
| Cost comparison of material and labour for a Bentley common gearbox and a Rover gearbox. | 11th Jun 1938 | Box 127 \ 3 scan0232 | |
| Confirming the arrival time and date of Capt. Wilks and Maurice Wilks at the Works. | 11th Jun 1938 | Box 127 \ 3 scan0233 | |
| Letter to The Rover Company Ltd. regarding a Wilmot-Breeden door lock. | 14th Jun 1938 | Box 127 \ 3 scan0234 | |
| Letter to The Rover Company Ltd. regarding a blueprint for seating dimensions and a future analysis of a sleeve valve engine. | 17th Jun 1938 | Box 127 \ 3 scan0235 | |
| Letter to Capt. S.B. Wilks of The Rover Company Ltd. regarding reports and the progress of a Wilmot-Breeden door lock. | 18th Jun 1938 | Box 127 \ 3 scan0236 | |
| Out-of-balance couple caused by sleeve valves in a 12-cylinder engine. | 29th Jun 1935 | Box 127 \ 3 scan0237 | |
| The design and performance of sleeve valves for car engines, comparing them to Wraith and Bentley engines. | 20th Jun 1935 | Box 127 \ 3 scan0238 | |
| Comparison of valve and piston area data for various engines. | 20th Jun 1935 | Box 127 \ 3 scan0239 | |
| Technical analysis of sleeve valve engine design, covering engine length, sleeve balance, and drive torque. | 20th Jun 1935 | Box 127 \ 3 scan0240 | |
| Graph comparing valve areas for sleeve and poppet valves in a 3.500 bore engine. | 16th Jun 1941 | Box 127 \ 3 scan0241 | |
| Blueprint comparing the cylinder blocks of a 6-cylinder 3.5 bore Sleeve Valve engine and a Big Bore Bentley engine. | 18th Jun 1935 | Box 127 \ 3 scan0242 | |
| Comparative tests of four different induction systems for the Bentley III and Bentley 50. | 10th May 1938 | Box 127 \ 3 scan0243 | |
| Comparison of Stromberg and S.U. carburettors, focusing on part throttle correction and pulsation effects. | 10th May 1938 | Box 127 \ 3 scan0244 | |
| Analysis of engine performance variations related to part throttle correction and the size of the induction pipe balance hole. | 10th May 1938 | Box 127 \ 3 scan0245 | |
| Letter from The Rover Company Ltd. regarding sleeve valve engines and Wilmot-Breeden door locks. | 21th Jun 1938 | Box 127 \ 3 scan0246 | |
| Letter from The Rover Company Ltd. to W.A. Robotham regarding a cost proposal for a 'body question'. | 21th Jun 1938 | Box 127 \ 3 scan0247 | |
| Letter to Captain Wilks at Rover Co. Ltd. requesting to purchase a Rover 16 gearbox for analysis. | 6th Jul 1938 | Box 127 \ 3 scan0248 | |
| Letter from The Rover Company Ltd. offering a new or reconditioned gearbox with prices and a discount. | 8th Jul 1938 | Box 127 \ 3 scan0249 | |
| Letter to The Rover Company Ltd. regarding an order for a re-conditioned gearbox. | 9th Jul 1938 | Box 127 \ 3 scan0250 | |
| Letter from the Rover Company Ltd concerning revisions to brake designs and materials. | 9th Jul 1938 | Box 127 \ 3 scan0251 | |
| Request to send a covering order to The Rover Co. Ltd. for a re-conditioned 10 HP gearbox. | 9th Jul 1938 | Box 127 \ 3 scan0252 | |
| Letter to The Rover Company Ltd. requesting a visit to see a new brake design. | 11th Jul 1938 | Box 127 \ 3 scan0253 | |
| Letter from The Rover Company Ltd. regarding a car with an experimental two leading shoe brake available for inspection. | 12th Jul 1938 | Box 127 \ 3 scan0254 | |
| Letter to The Rover Company Ltd. arranging to test a car with a two leading shoe brake. | 13th Jul 1938 | Box 127 \ 3 scan0255 | |
| Requesting the dismantling of a Rover gearbox for comparison with the B.50 model. | 15th Jul 1938 | Box 127 \ 3 scan0256 | |
| Letter from The Rover Company Ltd regarding 1939 gearbox drawings and a two-leading shoe hydraulic brake design. | 22th Jul 1938 | Box 127 \ 3 scan0257 | |
| Letter to Mr. Wilks of The Rover Company regarding a two-leading-shoe brake system and hydraulic application. | 29th Jul 1938 | Box 127 \ 3 scan0258 | |
| Letter from Rover regarding a two-leading-shoe brake design and negotiations with other companies. | 3rd Aug 1938 | Box 127 \ 3 scan0259 | |
| Brief letter of acknowledgement to M. Wilks of The Rover Company Ltd. | 4th Aug 1938 | Box 127 \ 3 scan0260 | |
| Letter to The Rover Co. Ltd. requesting contact information for their bonnet fastener supplier. | 26th Aug 1938 | Box 127 \ 3 scan0261 | |
| Confirming a material analysis will be carried out on a Rover Co. exhaust valve. | 9th Sep 1938 | Box 127 \ 3 scan0262 | |
| Letter to M. Wilks of The Rover Company Ltd. confirming an appointment. | 17th Sep 1938 | Box 127 \ 3 scan0263 | |
| Letter to Maurice Wilks of Rover discussing a gearbox failure and requesting competitor vehicle weight data. | 29th Oct 1938 | Box 127 \ 3 scan0264 | |
| Page 2 of a letter to M. Wilks, Esq. discussing pistons, combustion theories, motor show observations, and vehicle dynamics. | 29th Oct 1938 | Box 127 \ 3 scan0265 | |
| Letter to Rover requesting vehicle component weights and discussing engine torque. | 21th Nov 1938 | Box 127 \ 3 scan0266 | |
| Page 2 of a letter addressed to M. Wilks, Esq. concerning a query about when Boyle is arriving in Derby. | 21th Nov 1938 | Box 127 \ 3 scan0267 | |
| Graph plotting piston inertia torque for various engine cylinder configurations over a 360-degree cycle. | 25th Nov 1938 | Box 127 \ 3 scan0268 | |
| Letter to Capt. S.B. Wilks of The Rover Company Ltd, acknowledging his correspondence and passing it on. | 25th Nov 1938 | Box 127 \ 3 scan0269 | |
| From Rm. to RHC. forwarding a note from Wilks and asking for a response to his queries. | 25th Nov 1938 | Box 127 \ 3 scan0270 | |
| Letter from The Rover Company Ltd regarding a revised list of weights and a misunderstanding about V-engines. | 29th Nov 1938 | Box 127 \ 3 scan0271 | |
| List of component weights in pounds for a 12 HP Vauxhall car and a 12 HP Rover Sports Body. | 24th Nov 1938 | Box 127 \ 3 scan0272 | |
| Letter from The Rover Company inquiring about the manufacturing process for silent Bentley gearboxes. | 8th Dec 1938 | Box 127 \ 3 scan0273 | |
| Letter to G.H. Savage of The Rover Company Ltd. regarding setting axle gears and the production of single helical gears. | 9th Dec 1938 | Box 127 \ 3 scan0274 | |
| Letter to The Grosvenor Motor Co. Ltd. requesting a test drive of a Vauxhall to compare its steering. | 11th Aug 1922 | Box 127 \ 4 scan0001 | |
| Letter to Mr. Hives regarding the trial of a 25 & 30/98 Vauxhall car. | 14th Aug 1922 | Box 127 \ 4 scan0002 | |
| Letter to W. Watson & Co. arranging a trial of a Vauxhall car to inspect its steering at the Derby Works. | 15th Aug 1922 | Box 127 \ 4 scan0003 | |
| Letter from car dealer W. Watson & Co. regarding the logistics of collecting a new car and delivering a Vauxhall. | 17th Aug 1922 | Box 127 \ 4 scan0004 | |
| Letter from W. Watson & Co. proposing to send a Vauxhall car for examination. | 19th Aug 1922 | Box 127 \ 4 scan0005 | |
| Letter from W. Watson & Co. concerning the delivery and collection of a Vauxhall car for servicing. | 21th Aug 1922 | Box 127 \ 4 scan0006 | |
| Letter to W. Watson & Co. in Liverpool regarding the delayed arrival of a Vauxhall car due to weather. | 22th Aug 1922 | Box 127 \ 4 scan0007 | |
| Letter from a dealership regarding the delayed delivery of a Vauxhall car to Derby. | 23th Aug 1922 | Box 127 \ 4 scan0008 | |
| The particulars of Vauxhall steering systems. | 23th Aug 1922 | Box 127 \ 4 scan0009 | |
| The failure of the built-up crankshaft in the new Vauxhall sleeve engine. | 7th Jun 1926 | Box 127 \ 4 scan0010 | |
| Trial report on the 20/60 Vauxhall, detailing modifications to eliminate radiator wobble and improve engine smoothness. | 27th Jan 1930 | Box 127 \ 4 scan0011 | |
| Eliminating radiator movement through frame rigidity and suspension modifications. | 12th Oct 1936 | Box 127 \ 4 scan0012 | |
| Letter from Vauxhall Motors requesting sources for silico-manganese steel used in wrist pins. | 12th Oct 1936 | Box 127 \ 4 scan0013 | |
| Letter to Vauxhall Motors discussing steel sourcing for springs and a hardware problem with door wedges. | 15th Oct 1936 | Box 127 \ 4 scan0014 | |
| Letter discussing ongoing work on piston rings, a newly installed skid pan, and a potential visit to Vauxhall. | 15th Oct 1936 | Box 127 \ 4 scan0015 | |
| Letter to W.W. Appel of Vauxhall Motors arranging a works visit for Mr. Hives. | 16th Oct 1936 | Box 127 \ 4 scan0016 | |
| Letter from Vauxhall Motors Ltd to Mr. W.A. Robotham regarding an upcoming visit and information exchange on various components. | 19th Oct 1936 | Box 127 \ 4 scan0017 | |
| Letter to W.D. Appel of Vauxhall Motors regarding a visit and valve spring wire. | 20th Oct 1936 | Box 127 \ 4 scan0018 | |
| Travel arrangements for a visit to the Vauxhall Works in Luton. | 21th Oct 1936 | Box 127 \ 4 scan0019 | |
| Letter to Vauxhall Motors regarding a propeller shaft damper drawing and flywheel inertia. | 26th Oct 1936 | Box 127 \ 4 scan0020 | |
| Letter to Vauxhall Motors regarding the manufacture of Marles Double Tooth Steering gear. | 30th Oct 1936 | Box 127 \ 4 scan0021 | |
| Letter to the Chief Engineer of Vauxhall Motors regarding valve springs and a propeller shaft damper. | 2nd Nov 1936 | Box 127 \ 4 scan0022 | |
| Letter from Vauxhall Motors Ltd regarding valve spring and damper designs. | 3rd Nov 1936 | Box 127 \ 4 scan0023 | |
| Letter from Vauxhall Motors discussing a friction damper, or 'slug', used on a propeller shaft and its potential application. | 4th Nov 1936 | Box 127 \ 4 scan0024 | |
| Letter to Vauxhall Motors regarding discussions on cylinder bore finish and a proposed visit. | 12th Jan 1937 | Box 127 \ 4 scan0025 | |
| Letter to A. Taub of Vauxhall Motors regarding a forthcoming visit to Luton. | 12th Jan 1937 | Box 127 \ 4 scan0026 | |
| Test report investigating crankshaft bending in an experimental engine. | 14th Apr 1936 | Box 127 \ 4 scan0027 | |
| Test report on crankshaft bending in an experimental engine. | 13th Feb 1936 | Box 127 \ 4 scan0028 | |
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