The Golden hour clock glass hole is ¼ inch , glass diameter is 7in. .126in. thick.
Replacement motors have been available from time to time from most of the main clock repair parts suppliers. Check the gear on the motor , this may be the problem. The drive gears on the motors often get a groove worn in them from the dial glass gear. If this is the case check the glass to be sure it is not tight. Sometimes the dial glass breaks loose from the large gear that is attached to it. Do not oil the hands; the gear system will gum up and they will no longer work after a short while. If they are not working or are jammed then they either have already been oiled or they have become clogged with dust and / or corrosion. They must be cleaned. When a new motor is installed there MUST be play in the gears between the motor and the dial glass "ring" gear. If these two gears bind or are tight , either the clock will not work or the motor will heat up and wear out very quickly. There is some adjustment in the mounting screws for the motor on the inside of the case to prevent this problem. These will get warm when they run but they should not get too hot to touch. If they do get too hot to touch there is a problem, and the clock should not be allowed to run. Check the dial glass ; it should be loose. If it is tight and can't be moved it is binding and the clock will not work correctly.