Determine the Model ID of a Standard Terry-Type Movement (Model 5) - Step by Step
Based on Snowden Taylor's Chart of Terry-type 30-hour Shelf Clock MovementsImages courtesy of Pat Hagans (click on images to view full size)
Click on the or any value in the row just below the slanted queries.
Number of Possible Matching Model IDs: [matches are listed when number found <= 15]
XXXXXXXXXXXXXXXXXXXXXX
1. Strike wire arbors centered?
2. Figure 8 hole size and type?
3. Direction of count wheel wire?
4. Escape wheel bridge shape
5. Frontstrike wire pivot material ?
6. Verge pin button shape?
7. Access holes size?
8. Square hour shaft?
9. Strike wires rings or cups?
10. Wind arbors rings or cups?
Model ID
Maker(s)
Known Users
More Info
Image
1. Are the strike wire arbors centered with respect to the access holes?
Questions whether the strike wire arbors are centered (approximately) with respect to the centerline of the upper left access hole.
2. Is there a Figure 8 hole? If so, formed in what manner?
Questions whether a figure 8 hole is used to allow the count hook access to the count wheel. The entries are as follows:
If there is no figure 8 hole, "None";
if the figure 8 hole is made of three small holes, "SSS";
if of two large holes, "LL";
if of two small and one large hole, "SLS";
if of two small holes and one oval center hole, "SOS".
Small is defined as up to and including 9/16" diameter. Sometimes "SSS" holes are carved out to make a curved slot. Sometimes the holes in "SSS" are not all the same size.
3. In which direction is the count wheel retainer wire?
Refers to the direction of the count wheel retainer wire. The entries use a clock-hand notation; 12:00 means in the twelve o'clock direction. All movements observed can be categorized in three groups, as roughly 12:00, 4:30, and 7:00.
4. What form does the end of the escape wheel bridge have?
Questions whether the tip of the single-ended (usually brass) escape wheel bridge is round, rounded (but not round), or rectangluar (sometimes with corners bevelled); or whether a double-ended (usually wood) bridge is used.
5. Are the front strike wire pivots made from wood or steel?
Refers to the material of the front plate strike wire pivots. These may be wood, "W" or Steel "S". The entry "W/S" for example, means the upper pivot is wood and the lower pivot is steel.
6. What shape is the verge pin button?
Refers to the small brass button or plate to which the verge pin is attached. The shape of the plate is indicated as round "Rd" or rectangular "Rec".
7. What size are the access holes?
Questions whether the access holes in the corners of the movement are small or large, or are not present. It is marked "Sml", "Lrg", or "None". Small is defined as up to and including 9/16" diameter. This size figure is arbitrary, but is chosen as a size no commonly used.
8. Is there a square on the end of the hour shaft / clutch on the intermediate wheel?
Questions whether there is (or once was) a square on the end of the hour pipe, and the corresponding clutch on the intermediate wheel. The entry is "Yes" or "No". Rarely, a clutch exists with a round hour shaft. The entry for this would be "Yes / No".
9. Are there rings or cups around the front plate strike wire pivots?
Refers to whether there are rings or cups around the front plate strike wire pivots. No distinction between rings and cups is made. The entry is "Yes" or "No". If for example, there is no ring or cup around the upper strike wire pivot, while the lower does have a cup or ring, the entry is "No / Yes".
10. Are there rings or cups around the front plate winding arbors?
Refers, similarly, to rings or cups around the front plate winding arobors, and the entry is "Yes" or "No". If the winding arbors are bushed, the question is answered in the same way: "Yes" if there are rings on or around the bushings; otherwise, "No".