Brad93
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- 17,510
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- Essex, United Kingdom
I’m Pretty sure he did.He didn’t lap together
The three plate is to originate straightness from nothing
prior to him coming up with scraping with blue, they used to use a polishing compound on the three plates. The results were no where near as good. By scraping he could quickly knock down the high spots, then lap the three plates together when they were already quite flat. Joseph Whitworth literally came up with a ‘thou. The accuracy in machine tools and more importantly metrology equipment all followed on from his incredibly (for the time) flat planes.