Friday, May 03, 2013

The wooden mechanism secrets of master clockmaker John Harrison

Photo of clock movement

If you've read the book Longitude, you know that John Harrison was the man who created a clock capable of telling very accurate time while on a ship at sea. To accomplish this very difficult task, he develop many innovations. The video shown here uses a replica long case clock (commonly called a "Grandfather clock") to show the innovative elements of the wooden clock movement. Most of these new features have to do with reducing friction, minimizing the effects of temperature and humidity, and reducing wear. Worth noting are the use of the grasshopper escapement, Lignum Vitae bearings, a novel pinion design in which the trundles rotate, and adding gear teeth to a circular blank to ensure that each tooth is as strong as possibe.

For more on John Harrison, check out Dava Sobel's book, Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time.

Better still perhaps is the one with pictures titled, The Illustrated Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time

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Anonymous Andy from Workshopshed said...

I can also recommend reading Harrison by Jonathan Betts

May 3, 2013 at 8:39 AM  
Blogger DaveGoodchild said...

This fella is the main reason I got into loving mechanical things with lots of gears. He made me realise that if he could do what he did from scratch with no modern machine tools, cad design, or instant internet referencing than I could probably pull a simple wooden orrery out of the bag with all the bits and bobs I had kicking around in my workshop.
Mr Harrison - I thank you for the inspiration I needed to dive info the murky world of wooden gears and orrery manufacture.
I doff my cap to your genius. :-)

May 5, 2013 at 4:44 PM  
Blogger Dug North said...

Thanks for sharing that, Dave. Well, said too.

May 5, 2013 at 11:18 PM  
Blogger Dug North said...

Thanks for the other book recommendation, Andy!

May 5, 2013 at 11:18 PM  
OpenID said...

Love Longitude. The book is great, the documentary is good, and the feature film (starring Michael Gambon) is not half bad either. Harrison continues to inspire. I never knew about his wood gears though. Thanks!

May 7, 2013 at 1:05 AM  

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