I FIND over the time I have been repairing antique clocks that the above terms have been used and all come under the heading of the Longcase clock, also tall-case and floor clock.
Clocks of this style can vary in height from under 1.5 m (5ft) to over 1.8m (6ft ). The term granddaughter seems to be a clock smaller than 5ft; grandmother over 5ft and over 6ft is a grandfather which can be as high as 8.6 ft plus.
Most of the antique longcase clocks are over 6ft tall and have either an eight-day movement or 30-hour movement and date back to the 17th century. Those made from the early 20th century tend to have the modern strike or chime movements and are still available to the present day, as are the grandmother and granddaughter size clocks.
The early clocks with the 30-hour movement need to be wound daily, while the eight-day movement every week.
Eight-day clocks usually have two keyholes on either side of the dial, whereas the 30-hour styles have a single weight driving both the timekeeping and the striking mechanism and have no holes in the dial. However, some were made with false keyholes to make them look like the more expensive eight-day clocks.
In the early 20th century changes in size of houses made the smaller grandmother and granddaughter size more acceptable and many were made in the 20s and 30s with spring wound mechanism with both strike and chime movements; the larger grandfather size still having weights and, for the chime movement, three weights - one to drive the movement, one for the chime and the other for the strike and wound by chains instead of lines .
This is only a summary of the details which make up the longcase clock and there are many exceptions to this rule but this is a general basic guide to term of the LONGCASE Clock .
If you have a longcase clock which you would like more detail or information please feel free to ask at Bclocksunlimited@aol.com.I will do the best I can to answer.