| Description | Date | Identifier | |
| Further tests on a Bishop steering gear with an altered velocity ratio, detailing forward and reverse efficiency. | 17th May 1933 | Box 28 \ 2 Scan178 | |
| Follow-up letter from Adamant Engineering Company regarding suggestions for a Sports Bentley. | 17th May 1933 | Box 28 \ 2 Scan179 | |
| Dimensions and requirements for fitting a Marles Weller steering box and pendulum lever to a Bentley chassis. | 18th May 1933 | Box 28 \ 2 Scan180 | |
| Letter to Adamant Engineering Co Ltd discussing the feasibility and gear ratios for fitting a J.2. type steering to a Bentley vehicle. | 18th May 1933 | Box 28 \ 2 Scan181 | |
| Page 2 of a letter to The Adamant Eng. Co. Ltd. regarding pendulum levers and steering box options. | 19th May 1933 | Box 28 \ 2 Scan182 | |
| Letter from Adamant Engineering Co. Ltd. regarding the receipt of a Drop Arm for which no instructions were received. | 19th May 1933 | Box 28 \ 2 Scan183 | |
| Letter from Adamant Engineering Company discussing the feasibility and characteristics of manufacturing a special steering gear cam. | 20th May 1933 | Box 28 \ 2 Scan184 | |
| Letter discussing gear design alternatives, including helix angles, gear ratios, and rockershaft dimensions. | 20th May 1933 | Box 28 \ 2 Scan185 | |
| Letter from Adamant Engineering Company Limited regarding a 6¾' drop arm and a proposed meeting at the Derby works. | 20th May 1933 | Box 28 \ 2 Scan186 | |
| Letter to The Adamant Engineering Co. arranging a visit. | 22th May 1933 | Box 28 \ 2 Scan187 | |
| Letter from Adamant Engineering Company, Ltd. to arrange a meeting at the Rolls-Royce works. | 23th May 1933 | Box 28 \ 2 Scan188 | |
| Internal memorandum discussing the performance and cost issues of a new steering design and recommending alternatives. | 23th May 1933 | Box 28 \ 2 Scan189 | |
| Letter to The Adamant Engineering Co. Ltd confirming an appointment with Commander Matravers. | 24th May 1933 | Box 28 \ 2 Scan190 | |
| Drawing of a Marles-Weller J Type steering box, drawing GA 2450, adapted for a Bentley chassis. | 19th May 1935 | Box 28 \ 2 Scan191 | |
| Diagram illustrating the angular movement of a drop arm for a Marles steering box on a Bentley. | 18th May 1933 | Box 28 \ 2 Scan192 | |
| Efficiency tests on a Marles Weller type steering worm and nut using different lubricants. | 24th May 1933 | Box 28 \ 2 Scan193 | |
| Technical memorandum discussing issues with fitting Marles Weller steering components and proposing alternative damping solutions. | 24th May 1933 | Box 28 \ 2 Scan194 | |
| Note on American self-damping steering boxes and the potential for axle flutter at Brooklands. | 24th May 1933 | Box 28 \ 2 Scan195 | |
| Letter from Adamant Engineering Company, Limited confirming an appointment. | 25th May 1933 | Box 28 \ 2 Scan196 | |
| General arrangement of Marles Steering Gear L7 type RH. | 24th Apr 1930 | Box 28 \ 2 Scan197 | |
| Letter from Adamant Engineering Company regarding a 'J' Type Marles-Weller Steering Gear order. | 13th Jun 1933 | Box 28 \ 2 Scan198 | |
| Letter from CAM GEARS LTD. concerning the cost and invoicing of a special Bishop Steering Gear sample. | 15th Jun 1933 | Box 28 \ 2 Scan199 | |
| Letter to The Adamant Engineering Co. discussing steering gear for Bentley and Phantom models. | 15th Jun 1933 | Box 28 \ 2 Scan200 | |
| Letter to The Adamant Eng. Co. regarding the fitting of a Marles steering gear to a Bentley chassis. | 15th Jun 1933 | Box 28 \ 2 Scan201 | |
| Report on a Marles Weller steering gear before installation. | 15th Jun 1933 | Box 28 \ 2 Scan202 | |
| Letter to Cam Gears Ltd. regarding a Bishop Steering Gear, agreeing to a price and mentioning upcoming road tests. | 16th Jun 1933 | Box 28 \ 2 Scan203 | |
| Letter from Adamant Engineering Company regarding the supply and specifications of Marles steering gear components for a Bentley car. | 16th Jun 1933 | Box 28 \ 2 Scan204 | |
| Letter from Adamant Engineering Company suggesting a rockershaft movement for fitting a Marles Gear. | 16th Jun 1933 | Box 28 \ 2 Scan205 | |
| The acquisition of a 'Bishop' steering system for improvement purposes. | 20th Jun 1933 | Box 28 \ 2 Scan206 | |
| Issues with the Marles Weller steering system and considering it the worst feature on the big car. | 19th Jun 1933 | Box 28 \ 2 Scan207 | |
| Letter from Cam Gears Ltd. regarding an invoice for a sample steering gear and upcoming road tests. | 19th Jun 1933 | Box 28 \ 2 Scan208 | |
| The condition of a Marles Weller steering system after a 50-hour bumper test, noting a slight crack but continued functionality. | 21th Jun 1933 | Box 28 \ 2 Scan209 | |
| Letter from Adamant Engineering Company regarding a delay in dispatching a steering gear and a missing Drop Arm. | 22th Jun 1933 | Box 28 \ 2 Scan210 | |
| Requesting the dismantling of a Marles Weller steering unit from car 20-EX for inspection and return. | 23th Jun 1933 | Box 28 \ 2 Scan211 | |
| Letter to Adamant Engineering Co Ltd. regarding the modification and issues with steering components. | 23th Jun 1933 | Box 28 \ 2 Scan212 | |
| Letter from Adamant Engineering Company regarding modifications and parts for steering gears, including a bent back plate. | 26th Jun 1933 | Box 28 \ 2 Scan213 | |
| Letter to Adamant Engineering Co. Ltd. thanking them for the prompt dispatch of a shorter drop arm. | 27th Jun 1933 | Box 28 \ 2 Scan214 | |
| Letter from Adamant Engineering confirming the dispatch of drop arms for a Bentley car. | 29th Jun 1933 | Box 28 \ 2 Scan215 | |
| Examination report on the poor finish of a Marles-Weller 20-EX steering component, suggesting alternative manufacturing methods. | 6th Jul 1933 | Box 28 \ 2 Scan216 | |
| Diagram showing cracks and chipping in contact pads on a Marles Weller steering system. | 28th Jun 1933 | Box 28 \ 2 Scan217 | |
| Two invoices received from Adamant Engineering Co. without a corresponding purchase order. | 6th Jul 1933 | Box 28 \ 2 Scan218 | |
| Letter to Adamant Engineering concerning a steering conversion for a Phantom and issues with cracked hemispheres. | 6th Jul 1933 | Box 28 \ 2 Scan219 | |
| Examination report on the poor finish and manufacturing method of a Marles-Weller steering system. | 6th Jul 1933 | Box 28 \ 2 Scan220 | |
| Diagram illustrating cracks and chipping on contact pads for a Maples Weller steering system on a 20 Ex Chassis. | 28th Jun 1933 | Box 28 \ 2 Scan221 | |
| Letter from Adamant Engineering Company acknowledging receipt of a letter and an Inspector's report, and awaiting a gear for examination. | 7th Jul 1933 | Box 28 \ 2 Scan222 | |
| Confirming the satisfactory fitting of a 'J' type steering gear and authorising invoice payment. | 11th Jul 1933 | Box 28 \ 2 Scan223 | |
| Dispatch instructions for sending a Marles Weller Steering part for examination to Adamant Engineering Co. Ltd. | 15th Jul 1933 | Box 28 \ 2 Scan224 | |
| Advice note from Adamant Engineering Company, Ltd. acknowledging receipt of a returned steering gear. | 18th Jul 1933 | Box 28 \ 2 Scan225 | |
| Letter from Adamant Engineering Company regarding alterations to a steering gear cam ratio and a smaller steering sample for a Bentley. | 23th Aug 1933 | Box 28 \ 2 Scan226 | |
| Letter from the Experimental Department to Adamant Engineering regarding steering performance on Bentley and Phantom models. | 2nd Sep 1933 | Box 28 \ 2 Scan227 | |
| Letter from Cam Gears Ltd. requesting a report on the testing of a sample Bishop Steering Gear. | 8th Sep 1933 | Box 28 \ 2 Scan228 | |
| Letter from Adamant Engineering Company regarding a sample of Vacuum Mobiloil lubricant for steering gears. | 7th Sep 1933 | Box 28 \ 2 Scan229 | |
| Letter from Adamant Engineering Company discussing the suitability of Marles vs. Marles-Weller steering gears for Bentley and Phantom cars. | 8th Sep 1933 | Box 28 \ 2 Scan230 | |
| Letter from Adamant Engineering Company regarding steering box oil viscosity and hemisphere cracking on a Bentley car. | 8th Sep 1933 | Box 28 \ 2 Scan231 | |
| General arrangement of Marles steering gear L7 type RH. | 24th Apr 1930 | Box 28 \ 2 Scan232 | |
| Letter to Adamant Engineering Co. Ltd. discussing steering gear tests for Bentley and Phantom models. | 20th Sep 1933 | Box 28 \ 2 Scan233 | |
| Letter from Adamant Engineering Company regarding steering gears for Bentley and Phantom models. | 27th Sep 1933 | Box 28 \ 2 Scan234 | |
| Letter from the Experimental Department inviting an engineer to test drive a Bentley to demonstrate its worm and nut steering system. | 29th Sep 1933 | Box 28 \ 2 Scan235 | |
| Letter from Adamant Engineering Company to W. A. Robotham regarding an invitation to drive a Bentley car. | 30th Sep 1933 | Box 28 \ 2 Scan236 | |
| Letter from Cam Gears Ltd. regarding a visit to discuss a sample steering gear. | 24th Nov 1933 | Box 28 \ 2 Scan237 | |
| Letter from Adamant Engineering Company requesting the date of first use of an oscillating ball bearing assembly for patent negotiations. | 15th Dec 1933 | Box 28 \ 2 Scan238 | |
| Letter to The Adamant Engineering Co. regarding a query on a steering column thrust race. | 20th Dec 1933 | Box 28 \ 2 Scan239 | |
| Three blueprints for a spherical ball bearing in the steering gear unit. | 21th Dec 1933 | Box 28 \ 2 Scan240 | |
| Letter to Adamant Engineering Co. Ltd. providing blueprints and details for early steering components. | 22th Dec 1933 | Box 28 \ 2 Scan241 | |
| Letter from Adamant Engineering Company acknowledging receipt of a letter and enclosures from W.A. Robotham. | 27th Dec 1933 | Box 28 \ 2 Scan242 | |
| Letter from Adamant Engineering Company Ltd. to W.A. Robotham regarding the receipt of letters and drawings. | 9th Jan 1934 | Box 28 \ 3 Scan001 | |
| Letter from Cam Gears Ltd. following up on the testing of a Bishop Patent Steering Gear. | 1st May 1934 | Box 28 \ 3 Scan002 | |
| Letter to The Adamant Engineering Co. Ltd. requesting a drawing for a smaller 'Marles' type steering box for an Experimental 25 HP car. | 12th Sep 1934 | Box 28 \ 3 Scan003 | |
| Letter from Adamant Engineering Company regarding the suitability of a D.7 Marles steering gear for an experimental 25-HP car. | 13th Sep 1934 | Box 28 \ 3 Scan004 | |
| General arrangement of a Marles D7 Type PH steering gear assembly. | 15th Jul 1930 | Box 28 \ 3 Scan005 | |
| Order to be placed with Adamant Engineering Co. for a Marles Steering component. | 17th Sep 1934 | Box 28 \ 3 Scan006 | |
| Instructions for fitting a Marles steering column to a 20/25 HP chassis and an urgent request for a pendulum lever. | 17th Sep 1934 | Box 28 \ 3 Scan007 | |
| Decision to replace an unsatisfactory La Salle steering with a Marles gear and a request for sketches of adapting pieces. | 17th Sep 1934 | Box 28 \ 3 Scan008 | |
| Letter to Adamant Engineering Co. Ltd. regarding the replacement of a D.7 size steering column with a larger L.7 size on a 25 HP chassis. | 17th Sep 1934 | Box 28 \ 3 Scan009 | |
| Letter discussing requirements for attaching a steering column to a Marles box and requesting further prints. | 17th Sep 1934 | Box 28 \ 3 Scan010 | |
| Letter from Adamant Engineering Company confirming a verbal order for a Marles Steering Gear for an experimental 25-HP chassis. | 17th Sep 1934 | Box 28 \ 3 Scan011 | |
| To Roy regarding a price correction on an invoice for Adamant Steering. | 18th Sep 1934 | Box 28 \ 3 Scan012 | |
| Letter from Adamant Engineering Company regarding the fitment of a steering box to a 25-HP chassis. | 18th Sep 1934 | Box 28 \ 3 Scan013 | |
| Page two of a letter from Adamant Engineering Company Limited regarding a standard L7 R.H. Steering Column print. | 18th Sep 1934 | Box 28 \ 3 Scan014 | |
| General arrangement of Marles Steering Gear L7 Type RH. | 24th Apr 1930 | Box 28 \ 3 Scan015 | |
| Telegram from Robotham to Carlton-Smith enquiring about the dispatch of a Marles steering component. | 21th Sep 1934 | Box 28 \ 3 Scan016 | |
| Telegram advising of a delayed delivery for a special box due to alterations. | 21th Sep 1934 | Box 28 \ 3 Scan017 | |
| Telegram to Adamant, Luton, regarding the dispatch of a Marles steering box. | 27th Sep 1934 | Box 28 \ 3 Scan018 | |
| Telegram received by telephone regarding a consultation with Mr. H. Royce. | 27th Sep 1934 | Box 28 \ 3 Scan019 | |
| Despatch request for a Pendulum Lever to be sent to Adamant Engineering Co. | 28th Sep 1934 | Box 28 \ 3 Scan020 | |
| Letter to Adamant Engineering Co. Ltd. regarding the dispatch of a Drop Arm for a steering box. | 28th Sep 1934 | Box 28 \ 3 Scan021 | |
| Letter from Adamant Engineering Company confirming receipt of a Drop Arm and advising it will be returned by post. | 29th Sep 1934 | Box 28 \ 3 Scan022 | |
| The mechanical efficiency of a Marles Type L.7. R.H. Steering Box. | 11th Oct 1934 | Box 28 \ 3 Scan023 | |
| Data table showing pendulum lever load, torque, wheel torque, and efficiency for forward and reverse drive. | 11th Jun 1934 | Box 28 \ 3 Scan024 | |
| Mechanical efficiency of a La Salle steering box under static conditions. | 11th Jun 1934 | Box 28 \ 3 Scan025 | |
| Letter to Adamant Engineering Co. Ltd. discussing efficiency tests on a Marles steering gear compared to an American 'Saginaw' gear. | 18th Oct 1934 | Box 28 \ 3 Scan026 | |
| Addition of friction to a steering column via a spring-loaded gland to reduce road shocks. | 12th Oct 1934 | Box 28 \ 3 Scan027 | |
| Letter from Adamant Engineering Company discussing the efficiency of the L7 steering gear and the use of needle bearings. | 13th Oct 1934 | Box 28 \ 3 Scan028 | |
| Letter from Adamant Engineering regarding the design of a steering column, specifically the addition of friction using multi-shims. | 13th Oct 1934 | Box 28 \ 3 Scan029 | |
| Letter to The Adamant Engineering Co. Ltd. regarding the efficiency testing of a gear. | 15th Oct 1934 | Box 28 \ 3 Scan030 | |
| Double-toothed Marles Steering system with Adamant Engineering Co. | 17th Oct 1934 | Box 28 \ 3 Scan031 | |
| Letter from Adamant Engineering Company regarding the 'L7' gear and efficiency tests. | 17th Oct 1934 | Box 28 \ 3 Scan032 | |
| Letter to the Adamant Engineering Co. Ltd. regarding the heavy steering of an L.7 Type Steering Gear and requesting modifications. | 31th Oct 1934 | Box 28 \ 3 Scan033 | |
| Letter from Adamant Engineering Company discussing the specifications and efficiency of L7 Marles Steering gears. | 1st Nov 1934 | Box 28 \ 3 Scan034 | |
| Letter from Adamant Engineering comparing the features and potential efficiency of Marles Gear versus Worm and Nut steering. | 1st Nov 1934 | Box 28 \ 3 Scan035 | |
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