Flat Floor

I once visited the Boeing factory in Washington and there were a couple of things that I would have liked to see, but didn't. Instead of a giant pitched roof, the factory has a flat roof and a snowplough lives up there. They've also, apparently, got a bit of floor large enough to build a jumbo jet on that is flat and level to a few thousandths of an inch.

I used to be confused about measuring the suspension geometry of my car. When I do it at my mum's house I get good results and the numbers make sense. When I do it at home nothing adds up. One of my brothers once had to take an airliner apart and put it back together and have it come out exactly the same shape. He explained to me that it can't be done unless you are taking measurements from a floor which is flat and level. He didn't have a flat floor to work from but rather brilliantly made bits of one using dozens of scissor jacks, steel plates, and a laser level. I believe his crew were encouraged not to move them or kick them over while the job was in progress. I've got the same problem - my garage floor isn't flat.

If I were working for a racing team there would be an area of floor in the workshop that was known to be flat and level. In fact "flat floor" has now become a verb, you can have your car flat-floored, it doesn't mean that the floor is made flat, like "chiselled" it means that the tool is applied to the car - before the corner weights and geometry is adjusted. Cheapskates can't be choosers, and the car only touches the floor in four spots, so I have shimmed it up with cheep vinyl flooring tiles.

 In the racing team they would also have turntables or slip-plates to put the car on so that you can steer and adjust the wheels without putting any force on anything, my slip plates are made with more of the vinyl tiles - good side to good side with grease in between.

 They work better than I could have hoped.

Richard "Whitworth Three Plates Method" B