Machinist

[Lawrence London <lfljvenaura@gmail.com>]

The Newbould Indexer is the Smithsonian's 28th basic mechanism. From a NI site: we are accustomed of holding tolerances to a concentricity of .000020” and Is guaranteed to 50 millionths TIR. How it works: http://www.imperialnewbould.com/the-newbould-indexer.html

Here is a small collection of information and links I put together and posted to my machinist mailing list: https://lists.ibiblio.org/pipermail/machinist/2013-April/000081.html

Several explanations of how it works:

http://metalworkforums.com/f65/t200132-newbould-indexer

A 17 page thread started in 2008 at Practical Machinist started by RJ Newbould with an explanation of the mechanism by him:

The Mother of Invention https://www.practicalmachinist.com/vb/general-archive/ot-mother-invention-159279/

A video of a model of the Indexer at YouTube with an explanation by Newbould

Invented in 1972 by RJ Newbould, the Newbould Indexer is in the Smithsonian and listed as the 28th basic mechanism invented. https://youtu.be/3EGGuR5YziE ::: A description written by R J Newbould of the model shown is as follows; It indexes every 8 degrees. The top pitch is 24 degrees, making 15 teeth The bottom pitch is 16 degrees making 22.5 teeth. Odd tooth is marked in red. Difference = 8 degrees. Starts closed at zero degrees. Opens, indexes middle "adapter" disk one pitch of 16 degrees. Closes, top plate forced to rotate 8 degrees to engage. Repeats until end of clearance area, totaling 24 degrees rotation of top plate. Middle plate returns to start position, top plate stays at 24 degrees. Repeating would index another 24 degrees to total 48 degrees This means the adapter plate goes back and forth in the open area and effectively ratchets the top plate in 8 degree increments. Make the adapter plate free rotating, and you can set any 8 degree angle at random. Change pitches to suit for desired increments.

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Lawrence F. London, Jr.
lfljvenaura@gmail.com

https://sites.google.com/site/avantgeared