| Description | Date | Identifier | |
| Comparative table of specifications for various car models from the 1930s. | 8th Mar 1940 | Box 136 \ 2 scan0225 | |
| Specification sheet comparing various competitor cars from the 1930s. | 8th Mar 1940 | Box 136 \ 2 scan0226 | |
| Specification comparison sheet for a Humber Saloon and a Bentley Coupe. | 11th Mar 1940 | Box 136 \ 2 scan0227 | |
| Letter to Wolseley Motors Ltd. requesting outline drawings and torque curves for a small Cotal box for testing purposes. | 11th Mar 1940 | Box 136 \ 2 scan0228 | |
| Print of a Cotal gearbox from Wolseley Motors and outlining items requiring design attention for the Senior Range. | 12th Mar 1940 | Box 136 \ 2 scan0229 | |
| Following a visit to Morris Radiators, discussing car heater development and the potential use of a fin-and-tube radiator. | 14th Mar 1940 | Box 136 \ 2 scan0230 | |
| Request for blueprints of the GB. 5392 Gearbox. | 15th Mar 1940 | Box 136 \ 2 scan0231 | |
| Letter from Wolseley Motors discussing the availability and specifications of different sized Cotal gearboxes. | 15th Mar 1940 | Box 136 \ 2 scan0232 | |
| Continuation sheet of a letter from the Managing Director of Wolseley Motors Ltd. to W. A. Robotham. | 15th Mar 1940 | Box 136 \ 2 scan0233 | |
| Specification sheet for a Wolseley Motors 10/12 Mkg. Cotal Gearbox, detailing gear ratios and maximum input torque. | 15th Mar 1940 | Box 136 \ 2 scan0234 | |
| Request for blueprints of the GB. 5392 Senior Gearbox. | 15th Mar 1940 | Box 136 \ 2 scan0235 | |
| Providing particulars of the gear ratios and torque capacity for the small Cotal gearbox. | 18th Mar 1940 | Box 136 \ 2 scan0236 | |
| Specification sheet for a Wolseley Motors 10/12 Mkg. Cotal Gearbox, detailing gear ratios and maximum input torque. | 15th Mar 1940 | Box 136 \ 2 scan0237 | |
| Letter to Wolseley Motors Ltd regarding a drawing and testing of a small gearbox. | 18th Mar 1940 | Box 136 \ 2 scan0238 | |
| The return of loaned gearbox drawings and models to Mr. A.B. Oliver. | 18th Mar 1940 | Box 136 \ 2 scan0239 | |
| Letter to Mr. Oliver acknowledging the loan of models and drawings for a gearbox investigation. | 18th Mar 1940 | Box 136 \ 2 scan0240 | |
| Advising the forwarding of goods, specifically the return of loaned gearbox models and drawings. | 19th Mar 1940 | Box 136 \ 2 scan0241 | |
| Packing note for gearbox models and drawings being returned from loan. | 19th Mar 1940 | Box 136 \ 2 scan0242 | |
| Alteration notice for senior gearbox outer cones, deleting a peening note. | 19th Mar 1940 | Box 136 \ 2 scan0243 | |
| Letter from Wolseley Motors Ltd concerning the arrangement to send a 12 M.Kg Cotal Gear Box. | 19th Mar 1940 | Box 136 \ 2 scan0244 | |
| Requesting the clearing up of drawing office sections to complete the Senior Range Gearbox. | 20th Mar 1940 | Box 136 \ 2 scan0245 | |
| Design development of a die-cast head casing for a column gear shift for the Senior Range. | 24th Mar 1940 | Box 136 \ 2 scan0246 | |
| Letter from A.C. Oliver to Mr. Robotham regarding the 'Oliver' gearbox, offering to provide detail drawings and material records. | 26th Mar 1940 | Box 136 \ 2 scan0247 | |
| Confirming the receipt of a Cotal gearbox on loan as per an attached invoice. | 27th Mar 1940 | Box 136 \ 2 scan0248 | |
| Letter to A. Oliver acknowledging his correspondence about the 'Oliver' gearbox. | 28th Mar 1940 | Box 136 \ 2 scan0249 | |
| Conversation about gearbox design, spare wheel placement, and a universal coupling for a marine unit. | 29th Mar 1940 | Box 136 \ 2 scan0250 | |
| Letter to A.B. Oliver regarding a parcel of models and drawings sent to the wrong address. | 6th Apr 1940 | Box 136 \ 2 scan0251 | |
| Letter from C.B. Oliver confirming receipt of models and drawings and providing a new address. | 9th Apr 1940 | Box 136 \ 2 scan0252 | |
| Letter concerning the 'JOliver' gearbox, following up on returned models and drawings. | 26th Mar 1940 | Box 136 \ 2 scan0253 | |
| The stress analysis and treatment for helical fabroil gears. | 12th Apr 1940 | Box 136 \ 2 scan0254 | |
| Technical document detailing the calculation of the arc of contact for gear teeth. | 15th Apr 1940 | Box 136 \ 2 scan0255 | |
| Letter to Wolseley Motors Ltd. regarding the delayed return of a loaned Cotal gearbox for examination. | 15th Apr 1940 | Box 136 \ 2 scan0256 | |
| Alteration notice detailing the addition of a Vellumoid joint to a gearbox blanking cover. | 17th Apr 1940 | Box 136 \ 2 scan0257 | |
| Alteration notice for an L.H. Senior Range gearbox, detailing the addition of parts and the reason. | 17th Apr 1946 | Box 136 \ 2 scan0258 | |
| Modifications to fit a gearbox with steering column control to Left Hand Drive Senior Range cars. | 25th Apr 1940 | Box 136 \ 2 scan0259 | |
| Gearbox design modifications, including linkages, control mechanisms, and policies for various car models. | 25th Apr 1940 | Box 136 \ 2 scan0260 | |
| Revised gearbox with steering column control for Left Hand Cars in the Senior Range. | 25th Apr 1940 | Box 136 \ 2 scan0261 | |
| Gearbox modifications, controls, and adaptation for various car models, including the Silver Phantom. | 25th Apr 1940 | Box 136 \ 2 scan0262 | |
| Review and commentary on articles from the S.I.A. journal regarding electrically operated gearboxes. | 3rd May 1940 | Box 136 \ 2 scan0263 | |
| Manufacturing accuracy of internal parts, magnet winding difficulties, and balance issues concerning a gearbox. | 3rd May 1940 | Box 136 \ 2 scan0264 | |
| Gear tooth proportions for gearbox gears, including corrected and uncorrected types. | 25th Apr 1940 | Box 136 \ 2 scan0265 | |
| Note on the 'topping' of standard gears when meshed with corrected gears. | 3rd Apr 1941 | Box 136 \ 2 scan0266 | |
| Requesting the provisional allocation of 7 Senior Range Gearboxes and discussing engine fitting. | 30th Apr 1940 | Box 136 \ 2 scan0267 | |
| Provisional allocation of seven Senior Range Gearboxes and the potential for related machining work. | 30th Apr 1940 | Box 136 \ 2 scan0268 | |
| Reviewing three articles from the January/February 1940 S.I.A. Journal on electrically operated gearboxes. | 3rd May 1940 | Box 136 \ 2 scan0269 | |
| Manufacturing precision and balance issues of gearbox components, including magnet windings. | 3rd May 1940 | Box 136 \ 2 scan0270 | |
| Development of an electrically operated gearbox and suggesting a course of action. | 13th May 1940 | Box 136 \ 2 scan0271 | |
| Alteration to the dimensions of the Reverse Shaft and Gears due to a Drawing Office error. | 4th May 1940 | Box 136 \ 2 scan0272 | |
| The allocation of new senior range gearboxes to various chassis. | 14th May 1940 | Box 136 \ 2 scan0273 | |
| Alteration notice for a driving shaft bush (RG. 556) due to a drawing office error. | 17th May 1940 | Box 136 \ 2 scan0274 | |
| Revised scheme for the steering column support on the Senior Range, including the use of a Harris Bush. | 20th May 1940 | Box 136 \ 2 scan0275 | |
| Design of a gastight steering column seal for Senior Range cars with column gear shift. | 24th May 1940 | Box 136 \ 2 scan0276 | |
| Request to despatch a Bentley V. Gear Box for fitment to an experimental car. | 13th Jun 1940 | Box 136 \ 2 scan0277 | |
| Despatch request for a set of parts to be sent to Mr. Bellringer at Hythe Road, Willesden. | 3rd Jul 1940 | Box 136 \ 2 scan0278 | |
| The status of two Cotal gearboxes received from Wolseley Motors Ltd. | 15th Jul 1940 | Box 136 \ 2 scan0279 | |
| The retention of gearboxes for a minimum of six months without purchase. | 17th Jul 1940 | Box 136 \ 2 scan0280 | |
| Four schemes for the Junior gearbox and its column control. | 17th Jul 1940 | Box 136 \ 2 scan0281 | |
| PL.280 Synchromesh design, its characteristics, and a new method for pegging thrust washers. | 17th Jul 1940 | Box 136 \ 2 scan0282 | |
| Confirming the despatch of additional gearbox parts in reply to a previous memo. | 18th Jul 1940 | Box 136 \ 2 scan0283 | |
| Parts despatch request for BR/G at Hythe Road, Willesden. | 22th Jul 1940 | Box 136 \ 2 scan0284 | |
| Dispatch of parts for a Bentley Chassis No. B.V. | 22th Jul 1940 | Box 136 \ 2 scan0285 | |
| The ratio limitations and the economical radius for the magnetic clutches of the Cotal Gearbox. | 2nd Aug 1940 | Box 136 \ 2 scan0286 | |
| Analysis of magnet design and the particulars of teeth for a MK.30 gearbox. | 2nd Aug 1940 | Box 136 \ 2 scan0287 | |
| Reverse gear, gear ratios, and clutch torques for the MK.30 gearbox. | 2nd Aug 1940 | Box 136 \ 2 scan0288 | |
| List of references to publications concerning Cotal gearboxes. | 2nd Aug 1940 | Box 136 \ 2 scan0289 | |
| Technical memo detailing ratio limitations and clutch design considerations for the Cotal Gearbox. | 2nd Aug 1940 | Box 136 \ 2 scan0290 | |
| Magnet design and gear teeth specifications for the MK.30 box. | 2nd Aug 1940 | Box 136 \ 2 scan0291 | |
| Analysis of the MK.30 gearbox, detailing reverse gear ratios and torques on the four clutches. | 8th Aug 1940 | Box 136 \ 2 scan0292 | |
| List of references to journal articles about Cotal gearboxes. | 2nd Aug 1940 | Box 136 \ 2 scan0293 | |
| Confirming a request for an axle and gearbox from chassis B.4.AW and frame B.V.17. | 27th Aug 1940 | Box 136 \ 2 scan0294 | |
| Confirming the receipt of gear-boxes and rear axles from two chassis. | 3rd Sep 1940 | Box 136 \ 2 scan0295 | |
| Sending omitted change speed mechanism parts for Bentley Gear-boxes and Rear Axles. | 5th Sep 1940 | Box 136 \ 2 scan0296 | |
| Material and design of first speed teeth for the senior gearbox, referencing a 30,000-mile test. | 11th Oct 1940 | Box 136 \ 2 scan0297 | |
| Replacement and rebuilding of gearbox side shaft bearings for specific car chassis. | 24th Sep 1940 | Box 136 \ 2 scan0298 | |
| The gearbox from vehicle 30.G.VII, referencing associated reports and a file number. | 18th Sep 1940 | Box 136 \ 2 scan0299 | |
| Sending two blueprints for proposed tri-metal bushes for a Layshaft to Messrs Vandervell Ltd. | 3rd Oct 1940 | Box 136 \ 2 scan0300 | |
| Note about a gearbox from chassis 30.G.VII after 47,600 miles and a reference to related correspondence. | 23th Oct 1940 | Box 136 \ 2 scan0301 | |
| Testing of a Leyland gearbox on a bus chassis and requesting a comparison with in-house designs. | 23th Oct 1940 | Box 136 \ 2 scan0302 | |
| Lubrication of Layshaft Bearings, suggesting a drilled hole is unnecessary. | 21th Oct 1940 | Box 136 \ 2 scan0303 | |
| Agreeing to the deletion of a hole drilled in the second motion shaft for layshaft bearings. | 26th Oct 1940 | Box 136 \ 2 scan0304 | |
| Specification revision for a gearbox on Bentley Chassis 4-B-50, detailing removed and newly fitted parts. | 28th Nov 1940 | Box 136 \ 2 scan0305 | |
| Replacement of a gearbox on Bentley Chassis 1-B-50. | 28th Nov 1940 | Box 136 \ 2 scan0306 | |
| Requesting drawings for a side shaft sleeve, a camshaft modification, and a general arrangement of the Myth engine. | 27th Nov 1940 | Box 136 \ 2 scan0307 | |
| Internal memorandum discussing the design of a 3rd and 4th synchromesh spring loading key and an anti-rattle modification. | 12th Nov 1940 | Box 136 \ 2 scan0308 | |
| Chart comparing gearbox and rear axle ratios for various vehicle models. | 22th Jun 1938 | Box 136 \ 2 scan0309 | |
| Providing blueprints for a deepened key and rivet for a rationalised gearbox's 1st and 3rd motion shaft. | 25th Jan 1941 | Box 136 \ 2 scan0310 | |
| The completion of six gearboxes for the Senior Range and a request for a report on gear failures. | 9th Feb 1941 | Box 136 \ 2 scan0311 | |
| Replacement of parts in the Senior Range Gearbox servo drive to prevent water ingress. | 4th Mar 1941 | Box 136 \ 2 scan0312 | |
| Request for a photographic weight analysis and diagrammatic sketch of Morris and Vauxhall engines and gearboxes. | 30th Mar 1941 | Box 136 \ 2 scan0313 | |
| Specifications for 7 gearboxes and a request for parts for production chassis. | 10th Apr 1941 | Box 136 \ 2 scan0314 | |
| Design history and specifications for the Senior Range Gearbox. | 21th Feb 1941 | Box 136 \ 2 scan0315 | |
| Meeting notes detailing decisions made regarding gearbox revisions and component specifications. | 1st Feb 1941 | Box 136 \ 2 scan0316 | |
| Instructions for modifying a layshaft and bearing assembly, including dimensional changes for the shaft and bore. | 21th Feb 1941 | Box 136 \ 2 scan0317 | |
| From 'Rm' to 'HPS' requesting the production of various parts required for 7 gearboxes. | 11th Apr 1941 | Box 136 \ 2 scan0318 | |
| Implemented and pending modifications to Senior Range gearboxes. | 1st Mar 1941 | Box 136 \ 2 scan0319 | |
| Modifications to gearboxes, including strengthened speed dogs and changes to anti-rattle devices. | 3rd Jan 1941 | Box 136 \ 2 scan0320 | |
| PL.461 project for Gearbox 6' Centres, noting it as the origin for the PL.580 project. | 14th Mar 1941 | Box 136 \ 2 scan0321 | |
| Secret memorandum about rectifying incorrectly labelled photographs of gearbox failures. | 3rd May 1941 | Box 136 \ 2 scan0322 | |
| Sending corrected photographs for gearbox failures. | 7th May 1941 | Box 136 \ 2 scan0323 | |
| Test results and details for Ferobestos self-aligning gearbox bushes. | 7th May 1941 | Box 136 \ 2 scan0324 | |
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