It sounds like others have already given you more detailed information than I have, but for those with little or no knowledge of the technical details of period clocks and clock mechanisms, perhaps these files in the TIME section of the Florilegium might be of interest?
A-Gear-o-Time-art (5K) 9/ 1/99 "A Gear of Time" by Lord Xaviar the Eccentric.
http://www.florilegium.org/files/TIME/A-Gear-o-Time-art.html

clocks-msg (32K) 6/17/12 Medieval clocks and concepts of time.
http://www.florilegium.org/files/TIME/clocks-msg.html

Watches-art (5K) 9/ 1/99 "Watching Time Go By" by Lord Xaviar the Eccentric.
http://www.florilegium.org/files/TIME/Watches-art.html

Some related files in the same section:
bells-msg (21K) 9/18/01 Casting, construction and use of medieval bells. Bell sources.
http://www.florilegium.org/files/TIME/bells-msg.html

Dptych-Sndial-art (12K) 8/12/10 "A Diptych Sundial" by H.L. Morgaine Essex and H.L. Hucbald ap Urp.
http://www.florilegium.org/files/TIME/Dptych-Sndial-art.html

Sandglass-art (25K) 7/18/00 "History of the Sandglass" by RedDog.
http://www.florilegium.org/files/TIME/Sandglass-art.html

Time-Keeping-art (41K) 11/24/09 "A Brief History of Time Keeping" by Viscount Sir Corin Anderson (KSCA, OP).
http://www.florilegium.org/files/TIME/Time-Keeping-art.html

And I would still love to get and article or more details on this "GM", if this is the "Great Machine" that shows up at Lilies that I've heard about.

Thanks,
  Stefan

On Aug 1, 2013, at 12:58 AM, Jerry Harder <[log in to unmask]> wrote:

> I have been doing some research on clock escapements.  Turns out pendulum escapements aren't period by about 65 years.  Verge and foliot with a crown wheel where the pallets engage with opposite sides of the crown wheel are.  There are some verge and foiliot escapement designs which have 2 gears with pins that replace the crown wheel and the pallets both engage the top of these two pin gears.  I am looking to prove or disprove weather this type is also period.  Any help would be appreciated.  A simple search on firefox gives a great overview on wickipedia, and  www.youtube.com/watch?v=7HgAtCn3VUU shows the two pin-wheeled type.‎

--------
THLord Stefan li Rous    Barony of Bryn Gwlad    Kingdom of Ansteorra
   Mark S. Harris           Austin, Texas          [log in to unmask]
http://www.linkedin.com/in/marksharris
**** See Stefan's Florilegium files at:  http://www.florilegium.org ****