A flickr set of photos showing the workings of 3 clockjacks I have encountered.

http://www.flickr.com/photos/solvarr/sets/72157620082426510/

Items to elaborate on

• friction wear takeup screws
• conical bushings
• wear takeup plates
• fly wheel
• friction based ratchet

Note: Special thanks to Peter Ross for his kind help.

The opera di Bartolomeo

http://www.flickr.com/photos/bibliodyssey/3353004187/sizes/o/

A 1703 Reference

Mechanick exercises:Joseph Moxon

Start looking at page 39 of the book (page 50 of the google book)

or, The doctrine of handy-works. Applied to the arts of smithing, joinery, carpentry, turning, bricklayery. To which is added, Mechanick dyalling: shewing how to draw a true sun-dyal on any given plane, however scituated; only with the help of a straight ruler and a pair of compasses, and without any arithmetical calculation (Google eBook)

http://books.google.com/ebooks?id=t_IRCzjTf08C