Flat From Scratch (Whitworth 3 plates method)

How to make a true flat surface without a flat surface? Before any true flat surface was ever made there were only pseudo-flat surfaces, far to be really flat, a fact that had many implications in hampering the technological development. Who, for the first time, formalized a method to obtain a (quite) true flat surface (from scratch) was Joseph Whitworth who revealed his 3 plates method in a paper addressed to the British Association in Glasgow on 1840.
There are no much information online about this method, and the few lines mentioning it, that one could find in a book of mechanical technology, are not enough to let understand how actually this method can be carried out.
Eventually I found some information online, enough to try myself the method on the occasion to make the ways of my home made lathe.
Even in response to the requests from my esteemed viewers, having experienced myself the method, I provided in this video both the historical e technological context, and a detailed illustration on how I carried out this method, with some variations introduced to speed up the work.
I made this video with the hope others will find it interesting and useful.



0:15 Introduction
0:32 Historical reference

1:02 Historical limits due to the lack of true flat surfaces

2:27 My experiment
3:22 Why the need for flat surfaces
4:03 Definitions
5:18 Description of the method
9:31 Conclusions and acknowledgments



Acknowledgments

As I mentioned above, there is no much information online about this method, but digging the net eventually I came up to the original paper (a scan still available through Archive.org), its transcript on Wikipedia, and to a useful article written by Eric Weinhoffer that directed me to an other document, a PDF titled “Reference Planes” written by Doctor Alessandro Anzalone, for the Hillsborough Community College - Brandon Campus, both helped me a lot and confirmed what I intuitively figured out when I read the paper for the first time.
Many thanks to both the cited authors, without their work I would not have been able to get the results I got.


LINKS

The Whitworth method presented in 1840 in “Miscellaneous Papers on Mechanical Subjects”, with the paper titled “A Paper on Plane Metallic Surfaces or True Planes”:


Blog article of Eric Weinhoffer


Reference Planes by Alessandro Anzalone, Hillsborough Community College, Brandon Campus


Wikipedia page on Sir Joseph Whitworth:

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