The fact Rearsby produced clutch plates is an interesting story and worth recording.
We produced one part number only. The Austin-Morris A Series ‘Solid Centre’ clutch plate. The really good news was the volume - 12,000 a week. This plate fitted the Mini 1100/1300, Allegro etc, in fact all current and past A Series transverse engines and gearboxes since 1959. As a wearable part, it enjoyed good aftermarket sales via Unipart worldwide. That Rearsby had this volume product was good fortune indeed.
In 1957 when Alec Issigonis at The Austin, Longbridge, was designing the transverse engine Mini, he wanted a diaphragm sprung clutch, not the bulkier conventionally sprung clutch (made up of a series of compression springs arranged in a pitch diameter circle). Borg & Beck, who had a reputation for arrogance, said "It can't be done!"
Henry Ford observed "Experts know too many ways why you can't do something." So true I have discovered. Issigonis knew this too and was also pretty arrogant. He designed the diaphragm clutch himself. The clutch cover and diaphragm were sourced on Pressed Steel Fisher (part of BMC by then), and the clutch plate on a small company with clutch plate manufacturing expertise called Power Jacks, of Watford. Alford and Alder later acquired Power Jacks, up the road in Hemel Hempstead and later production was transferred Watford to A&A.
The MD of Power Jacks, Les Wharton (a canny businessman who would go on to become MD of Leyland Vehicles and then of Austin-Rover) was offered the job of running Rearsby Automotive following the Watford closure. He accepted the role, providing he could bring the Mini clutch plate with him, pointing out it was an ill fit to A&A's product range of suspension, steering and axles. Les knew, of course, the Mini plate was a very nice earner indeed! The rest as they say, is history. Les went on to try to buy Rearsby in the 1970s but was unsuccessful.
During the Austin Metro development, John Ebrey, Senior Transmission Design/Development Engineer in the ADO Longbridge, called us in to say they needed to fit a sprung-centre driven clutch plate to Metro, probably across the entire A Series engine-transmission range. Since Rearsby had no design/development expertise, they were forced to go to Borg & Beck. This was a real blow with serious implications for Rearsby profitability. Don Walker had a moment of inspiration, "Whose clutch technology do you admire?" My instant response, "Valeo". Don, "Who are they?" I replied, "French!"
Two weeks later, Don and I walked René Billet, Head of Embrayage Design Engineering (clutch design) and Jac Alas, Chief Development Engineer into Embrey's office. Within half an hour they were fully engaged professional-to-professional, in spite of faltering French and English. Jac asked if they had a prototype Metro with the Solid Centre ‘problem clutch’ installed. With the hour he returned from his test drive and confirmed the vehicle suffered a 'shunt' at 45 mph (shunt is when a series of resonances combine together to give a vibration. Although by no means the primary purpose of the clutch plate, by tuning the spring rate of a sprung-centre clutch, it can be used to separate some of the resonances, thus eliminating the shunt).
Jac further observed, at tick-over, the A Series transverse drive train suffered idler rattle. This was a well known ‘feature’ of the ubiquitous A Series engine/ transmission.
John explained the issue had been present since 1959 when Issigonis turned the engine 180 degrees to avoid Carburetor icing, which emerged during the original Mini development. This necessitated adding an idler gear to account for the engine running 'backwards' as a result of the change. Jac announced he could eliminate idler rattle too! He achieved this by simply placing the lowest rated sprung-centre springs in opposition. No on cost whatsoever, after 20 years and several million A Series transverse production of idler rattle. Borg & Beck were unaware.
We won the business, manufacturing the clutch driven plate for 10 years under license to Valeo.
One early result from our own design efforts was on the A Series sold centre plate. The original Issigonis design was a complex affair from a manufacturing and cost point of view. An expensive machined large diameter splined forged hub, eight quadrants, riveted to the hub with eight rivets, sandwiching 12 penny spring washers and a pair of friction linings fastened by 12 rivets. An assembly of high cost. I asked Leon Wachnianin, our splendid Chief Design Engineer, to come up with a lower cost design for the aftermarket, which was highly competitive and would have many alternative aftermarket offerings.
Nothing happened. This, in my experience, isn't unusual. Extra work isn't welcomed. The worry… not done this before, let's hope he forgets it. Keep your head down or we will be on the list of things to do! Maybe.
I had learned designers come from two distinct groups Innovators or Adapters. The first group are ‘off the wall’ characters; wild, unruly, non-conformers, blank sheet of paper folk .e.g. Spike Milligan, Steve Jobs.
Adapters see an idea, perhaps in a totally unrelated area, see possibility and adapt it to a need - for example James Dyson. Leon, I observed, was an excellent Adapter. He had to see something to adapt.
I took a machined hub and asked Paddy Fitzsimons, legendary Twilight Shift Foreman to make a single disc of steel to a sketch I had made. This disc had pockets cut into the outer diameter. I then fashioned, with two pliers, a wavy form in the metal between the cutouts to create the cushion between the pair of friction linings, previously provided by the 12 penny spring washers. Paddy then drilled and riveted a pair of friction linings onto the big single wavy disc.
I presented this to Leon (I hadn't forgot, it wasn't a whim). He now had a model. He could see.
I had achieved a massive part count reduction, 43 parts in the Issigonis design down to 30 parts - a significant reduction. And I proposed that the hub be a sintered part. Powdered steel particles pressed together in die and then heat treated to bond (sinter) the particles together. No machining at all (my final year project at university had been to explore and test sintered metal capability). The problem was to be controlling the shape of the heat treated centre disc with the cushion forms. I introduced Leon to the concept of stress analysis via making model in perspex and subjecting the models to stress, examining the 'rainbow' effect under special light sources, showing where high concentrations of stress occurred within the structure. Often by removing the metal this reduced the stress concentrations.
We used the facilities of a local university. I then contacted the MD of the British School of Motoring who ran a fleet of Austin Metros in their driving schools. I persuaded him to let us install six prototype clutch plates in six of his cars. Two each in Leicestershire, Nottinghamshire and hilly Derbyshire. Our new plate was a success - technically and commercially. Unipart were thrilled to have a low cost competitive driven plate.
We saved the clutch plate business. But in 1979 Chrysler decided to axe their losses in the UK and close all the ex-Rootes Group plants. Therefore we lost the Avenger axle tube business - a significant blow, but all in the normal course.
However on top of this . . .