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CAVE: Bristol 447 clock drive motor

Started by t.d.atwood@att.net, 11/13/2011 08:19PM
Posted 11/13/2011 08:19PM Opening Post
I am looking for a replacement motor for the Bristol 447 clock drive motor on my CAVE 12.5-in reflector (circa 1957)--I Googled it and an article says Cramer makes a replacement for this Bristol motor, but when I telephoned them last week I learned that replacement motor is no longer being manufactured. Any suggestions?

Terry Atwood
Shreveport, LA
Posted 11/14/2011 04:48PM #1
Any clock makes two "hour hand rotations" in 24 hours. Any set of gears with a 2:1 ratio will work. the greater number of teeth in each gear, the greater the accuracy. 10:20 is good. 50:100 better, etc. I once made a barn door rig which worked perfectly for exposures less than 1 hour.