| Description | Date | Identifier | |
| Evaluating the Buckley Patent Adjustable Tappets. | 20th Mar 1935 | Box 158 \ 4 scan0023 | |
| Requirements for adjustable tappet mechanisms and concluding that the Buckley patent device is unsuitable. | 2nd Apr 1935 | Box 158 \ 4 scan0024 | |
| Rejecting a proposed improvement for Cadillac Automatic Tappets after comparison with a previous design. | 5th Apr 1935 | Box 158 \ 4 scan0025 | |
| Confidential letter regarding a new 'Valve Slack Adjuster' design, seeking an opinion on its potential improvement over an existing patent. | 11th Mar 1935 | Box 158 \ 4 scan0026 | |
| Extract of a letter from General Motors Corporation regarding a valve and slack adjuster mechanism. | 9th Jan 1935 | Box 158 \ 4 scan0027 | |
| The design and experimental determination of parameters for a spherical valve and plunger mechanism. | 12th Nov 1935 | Box 158 \ 4 scan0028 | |
| Letter from Rudge-Whitworth Ltd requesting drawings for valve lift diagrams and tappet arrangements. | 12th Nov 1935 | Box 158 \ 4 scan0029 | |
| Letter to Rudge-Whitworth Ltd. enclosing drawings for self-adjusting tappets and requesting information on hardened piston rings. | 16th Nov 1935 | Box 158 \ 4 scan0030 | |
| Letter from a supplier discussing their design and manufacturing practices for valve springs. | 18th May 1936 | Box 158 \ 4 scan0031 | |
| Technical discussion on valve spring surge, calculation methods, and wire material selection. | 18th May 1936 | Box 158 \ 4 scan0032 | |
| Letter detailing the manufacturing process for valve springs, including heat treatment and shot blasting. | 8th Jun 1936 | Box 158 \ 4 scan0033 | |
| Technical memo discussing research on valve springs, their permissible stress range, and performance comparisons. | 8th Jun 1936 | Box 158 \ 4 scan0034 | |
| Graph showing the average stress range for good carbon steel wire and total static stress variation on valve springs. | 6th Jun 1936 | Box 158 \ 4 scan0035 | |
| Graph illustrating the endurance stress range for S/CV valve springs. | 6th Jun 1936 | Box 158 \ 4 scan0036 | |
| Letter to the Wilcox-Rich Valve Corporation inquiring about American practices for exhaust valves and valve seats to prevent erosion. | 12th Jun 1936 | Box 158 \ 4 scan0037 | |
| Specification sheet for ordering compression springs and the calculation for stress. | 12th Jun 1936 | Box 158 \ 4 scan0038 | |
| Page of calculations for determining the stress and wire size for springs, including formulas and worked examples. | 12th Jun 1936 | Box 158 \ 4 scan0039 | |
| The formula for calculating spring deflection with worked examples. | 12th Jun 1936 | Box 158 \ 4 scan0040 | |
| Page detailing calculations for helical compression springs and formulas for square wire springs. | 12th Jun 1936 | Box 158 \ 4 scan0041 | |
| Page discussing a spring design formula from a 1925 S.A.E. Journal and introducing a subsequent table of formulas. | 12th Jun 1936 | Box 158 \ 4 scan0042 | |
| Page detailing formulas and design considerations for round and square wire springs. | 12th Jun 1936 | Box 158 \ 4 scan0043 | |
| Graph showing the actual stress curve of helical compression springs. | 12th Jun 1936 | Box 158 \ 4 scan0044 | |
| Table of suggested total stress for helical compression springs made of various materials. | 12th Jun 1936 | Box 158 \ 4 scan0045 | |
| Page detailing the B-G-R formula for the quick computation of vibration frequency. | 12th Jun 1936 | Box 158 \ 4 scan0046 | |
| Specification sheet outlining formulas and constants for calculating extension springs. | 12th Jun 1936 | Box 158 \ 4 scan0047 | |
| Page of calculations for spring properties including stress, energy, and modulus of resilience, with a worked example. | 12th Jun 1936 | Box 158 \ 4 scan0048 | |
| Calculations for spring resilience, energy absorption, and material weight. | 12th Jun 1936 | Box 158 \ 4 scan0049 | |
| Specification guide for ordering torsion springs, including calculation formulas and diagrams of various types. | 12th Jun 1936 | Box 158 \ 4 scan0050 | |
| Reference table of the third and fourth powers of various wire diameters. | 24th Jun 1936 | Box 158 \ 4 scan0051 | |
| Letter from Wilcox-Rich Corporation informing of the death of Mr. Robert Jardine. | 24th Jun 1936 | Box 158 \ 4 scan0052 | |
| Letter from Wilcox-Rich Corporation regarding American practices on engine inserts and valve seats. | 23th Jun 1936 | Box 158 \ 4 scan0053 | |
| Letter from Wilcox-Rich Corporation regarding an ideal combination of austenitic type valves and Stellite-faced inserts. | 23th Jun 1936 | Box 158 \ 4 scan0054 | |
| Graph of safe stress ranges for valve spring wire, comparing Chrome-Vanadium and Carbon Steel. | 10th Sep 1936 | Box 158 \ 4 scan0055 | |
| Letter from Ethyl Export Corporation enclosing a memorandum on valve steels and arranging a meeting in Derby. | 10th Sep 1936 | Box 158 \ 4 scan0056 | |
| Bulletin detailing the composition and naming conventions of Silchrome 'X' series valve steels. | 10th Sep 1936 | Box 158 \ 4 scan0057 | |
| The properties and potential use of a new steel compared to Silchrome. | 18th Sep 1936 | Box 158 \ 4 scan0058 | |
| Request for assistance with valve spring failures on a new 12-cylinder car. | 18th Sep 1936 | Box 158 \ 4 scan0059 | |
| Letter from Barnes-Gibson-Raymond Inc. regarding the design and specification of springs. | 28th Sep 1936 | Box 158 \ 4 scan0060 | |
| Material standard specification for valve spring steel wire. | 28th Sep 1936 | Box 158 \ 4 scan0061 | |
| Material standard sheet detailing physical properties, surface requirements, and size variations for wire. | 28th Sep 1936 | Box 158 \ 4 scan0062 | |
| Material standard sheet detailing the procedures for steel inspection, rejections, and replacements. | 10th Oct 1936 | Box 158 \ 4 scan0063 | |
| Letter to Barnes-Gibson-Raymond Inc. regarding the production of valve springs for a Bentley vehicle. | 10th Oct 1936 | Box 158 \ 4 scan0064 | |
| Graph plotting the average stress range for good carbon steel wire against various automotive components. | 10th Oct 1936 | Box 158 \ 4 scan0065 | |
| Fatigue limit diagram for Steel #1, with stresses calculated by the Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0066 | |
| Stress-Strain diagram for Steel #1, showing Torsion and Tension curves and material properties. | 10th Oct 1936 | Box 158 \ 4 scan0067 | |
| Fatigue limit diagram for Steel #1A, with stresses calculated by the Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0068 | |
| Stress-strain diagram for Steel #1, showing both torsion and tension curves. | 10th Oct 1936 | Box 158 \ 4 scan0069 | |
| Fatigue limit diagram for pretempered wire steel #4. | 10th Oct 1936 | Box 158 \ 4 scan0070 | |
| Stress-strain diagram for pretempered wire steel, showing both tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0071 | |
| Fatigue limit diagram for pretempered wire steel, with stresses calculated by the Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0072 | |
| Stress-strain diagram for pretempered wire steel #7, showing tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0073 | |
| Fatigue limit diagram for special tempered steel number 11. | 10th Oct 1936 | Box 158 \ 4 scan0074 | |
| Stress-strain diagram for Special Tempered Steel #11, showing both tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0075 | |
| Fatigue limit diagram for special cold drawn spring steel #12, with stresses calculated by Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0076 | |
| Stress-strain diagram for special cold drawn spring steel #12, showing tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0077 | |
| Fatigue limit diagram for Silico-Manganese Steel #8. | 10th Oct 1936 | Box 158 \ 4 scan0078 | |
| Stress-Strain diagram for Silico-Manganese Steel #8, showing tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0079 | |
| Stress-strain diagram for Stainless Steel #9, showing tension and torsion curves. | 10th Oct 1936 | Box 158 \ 4 scan0080 | |
| Fatigue limit diagram for stainless steel calculated by Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0081 | |
| Fatigue limit diagram for High Manganese Steel #13, with stresses calculated by Wahl formula. | 10th Oct 1936 | Box 158 \ 4 scan0082 | |
| Stress-strain diagram for High Manganese Steel #13, detailing tension and torsion curves. | 14th Oct 1936 | Box 158 \ 4 scan0083 | |
| Letter from Coventry Climax Engines Ltd. regarding the delayed announcement of the Skinner Slide Valve Engine. | 14th Oct 1936 | Box 158 \ 4 scan0084 | |
| Letter from Barnes-Gibson-Raymond forwarding three lots of spring samples for testing. | 19th Oct 1936 | Box 158 \ 4 scan0085 | |
| Improving carbon steel wire production methods and commissioning experiments with supplier Geo. Fox & Co. | 27th Oct 1936 | Box 158 \ 4 scan0086 | |
| Letter to The Tempered Spring Co. Ltd. requesting a trial production of 24 valve springs from 'Low carbon steel'. | 27th Oct 1936 | Box 158 \ 4 scan0087 | |
| Specification and analysis sheet for a valve spring outer. | 14th May 1936 | Box 158 \ 4 scan0088 | |
| Sourcing Hard Drawn Piano Wire for valve springs and clarifying the oil tempering process. | 28th Oct 1936 | Box 158 \ 4 scan0089 | |
| Letter from The Tempered Spring Company Limited regarding the production of twenty-four trial valve springs. | 28th Oct 1936 | Box 158 \ 4 scan0090 | |
| Letter to Coventry Climax Engines expressing interest in their Overhead Inlet Side Valve Exhaust Units. | 29th Oct 1936 | Box 158 \ 4 scan0091 | |
| Request to purchase and test Ford V-8 valve tappets for material and hardness analysis. | 31th Oct 1936 | Box 158 \ 4 scan0092 | |
| Inquiry to The Tempered Spring Co. Ltd. regarding the manufacturing process of valve springs. | 2nd Nov 1936 | Box 158 \ 4 scan0093 | |
| Inquiry to The Lion Spring Co. regarding the manufacturing process of valve springs made from Swedish wire. | 2nd Nov 1936 | Box 158 \ 4 scan0094 | |
| Order for valve springs from the Vauxhall Co. | 2nd Nov 1936 | Box 158 \ 4 scan0095 | |
| Letter from The Tempered Spring Co. Ltd. regarding the production of valve springs from special Swedish wire. | 3rd Nov 1936 | Box 158 \ 4 scan0096 | |
| Letter from Vauxhall Motors Ltd acknowledging receipt of a letter but requesting a copy of a missing report. | 3rd Nov 1936 | Box 158 \ 4 scan0097 | |
| Letter to Vauxhall Motors Ltd. enclosing a Micro-Examination Report on a valve spring. | 4th Nov 1936 | Box 158 \ 4 scan0098 | |
| Letter to The Tempered Spring Co., Ltd. requesting a delivery date for 24 valve springs. | 4th Nov 1936 | Box 158 \ 4 scan0099 | |
| Valve spring particulars for Rover vehicles, listing suppliers. | 4th Nov 1936 | Box 158 \ 4 scan0100 | |
| Letter from The Lion Spring Company regarding the manufacturing process of valve springs from Swedish wire. | 4th Nov 1936 | Box 158 \ 4 scan0101 | |
| Request to The Lion Spring Co. Ltd. for trial valve springs made from low carbon steel. | 5th Nov 1936 | Box 158 \ 4 scan0102 | |
| Letter from The Tempered Spring Co. Ltd. regarding a delay in despatching special valve springs. | 5th Nov 1936 | Box 158 \ 4 scan0103 | |
| Request to pass an official order to The Tempered Spring Co. Ltd. for 24 valve springs for Bentley. | 16th Nov 1936 | Box 158 \ 4 scan0104 | |
| Letter to The Tempered Spring Co. Ltd. acknowledging receipt of 24 valve springs for an Endurance engine test. | 16th Nov 1936 | Box 158 \ 4 scan0105 | |
| Letter to The Tempered Spring Co. regarding a failed valve spring and an urgent order for new ones. | 24th Nov 1936 | Box 158 \ 4 scan0106 | |
| Letter to The Tempered Spring Co. discussing the laboratory analysis of a broken valve spring and requesting a delivery date for a new order. | 28th Nov 1936 | Box 158 \ 4 scan0107 | |
| Letter to The Tempered Spring Co. about a delay in receiving sample springs and a request for an additional set. | 4th Dec 1936 | Box 158 \ 4 scan0108 | |
| Requesting official orders to be placed for two sets of 24 valve springs. | 4th Dec 1936 | Box 158 \ 4 scan0109 | |
| Acquisition and proposed testing of Swedish wire for various engine valve springs. | 17th Dec 1936 | Box 158 \ 4 scan0110 | |
| Letter to The Tempered Spring Co. regarding the receipt and testing of a batch of valve springs. | 17th Dec 1936 | Box 158 \ 4 scan0111 | |
| Requesting an order of Swedish wire for making new Phantom III single valve springs. | 22th Dec 1936 | Box 158 \ 4 scan0112 | |
| The substitution of Ubas steel with a low carbon case hardening mild steel for chassis parts. | 22th Dec 1936 | Box 158 \ 4 scan0113 | |
| Extract from a letter received from the Rover Co. concerning complaints of broken valve springs. | 23th Dec 1936 | Box 158 \ 4 scan0114 | |
| Micro-examination report investigating a broken valve spring from a Bentley B-114-HK. | 30th Dec 1936 | Box 158 \ 4 scan0115 | |
| Requesting the experimental production of chassis valve springs from Swedish wire. | 4th Jan 1937 | Box 158 \ 4 scan0116 | |
| Valve lubrication schemes, specifically the wedge and felt systems, in relation to a 15,000-mile test on the 35-EX model. | 15th Jan 1937 | Box 158 \ 4 scan0117 | |
| Confirming an urgent request for differentially coiled valve springs made from carbon wire. | 28th Jan 1937 | Box 158 \ 4 scan0118 | |
| Status of coiling differentially-coiled valve springs, awaiting material from Sweden. | 30th Jan 1937 | Box 158 \ 4 scan0119 | |
| Letter to The Tempered Spring Co. regarding the satisfactory performance of 'Swedish Wire' springs and a request for further sets for testing. | 10th Feb 1937 | Box 158 \ 4 scan0120 | |
| Request and confirmation to order 6 sets (72) of valve springs from the Tempered Spring Co. | 15th Feb 1937 | Box 158 \ 4 scan0121 | |
| New, closely coiled valve springs made from Swedish wire, requesting they be fitted to B-17 and B-9 test engines. | 15th Feb 1937 | Box 158 \ 4 scan0122 | |
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