Highlights of Past Exhibits


The Handcrafting of Clock Movements, from the exhibit Time Made Visible:

Before the industrialization of clock making, the precise handcrafting of clock movements from cast brass, forged iron, and steel was an extraordinarily time-consuming process.

To begin the construction of a clock movement, plates and wheels were cast from brass, then hammered to harden them. After it had been filed flat, each wheel blank had a hole drilled in its center, and was turned on a lathe arbor, or turn, until its diameter was made true. These wheels became gears when teeth were cut with a clockmaker's engine. Small steel parts were also machined, and pinions (small-toothed wheels driven by the gears) were forged, filed, and tempered. Riveting the gears into place on their arbors, or axles, completed the assembly of the movement.

Clock dials were cast or cut from brass, which was then hammered, filed, polished and sometimes engraved. Finally, holes were drilled for the arbors and dials. The entire process involved workers with many different skills.

The following is a brief description of some of the specialized tools employed by clockmakers. Generally, we do not distinguish between watchmakers and clockmakers, although their tools may have been somewhat different, e.g., in size.
Unless otherwise noted, all tools are from the collection of the Museum.

Balance Truing Caliper, 1889-1899
E.F.B. & Company
[possibly Ezra F. Bowman & Company, Lancaster, PA]

This tool was used by a watchmaker to true a balance wheel. The pivots of the wheel were placed into tiny depressions in the arms of the caliper. The adjustable index was then moved close to the edge of the balance wheel, which was spun to see if it were true (straight) prior to balancing (poising). Modern versions of this tool are still in use today.
Die (Screw) Plate
19th century

Used to cut threads on tiny screws. Each hole is a die that forms a screw by cutting threads on a piece of wire as it is rotated through the hole. The size of the holes suggests that this is primarily a watchmaker's tool.

Files, 19th century

Files were used to shape and finish metal for such operations as making and fitting wheels and plates. Files of many shapes and tooth sizes were vital tools for the clock or watch maker.

Rivet Extracting Pliers, 19th century
Brass, Steel

Collection of Mr. William Wilson

Used to remove rivets from various clock parts.

Jeweler's Piercing Saw, 19th century
Iron, wood, steel, brass

To make an interior cut in a workpiece, the blade of the piercing saw was removed by loosening the thumbscrew near the handle. After being inserted in a hole drilled for the purpose, the blade was replaced and the cut was made. Pierced work is common on the ends of clock hands.

Staking Tool, 1881-1892
].G. Hall Manufacturing Company, Roxbury, Vermont
Cast iron, steel

This watchmaker's tool was invented by J. G. Hall. The vertical plunger was used with a variety of "stakes" with different sized or shaped ends for placing rollers and balance wheels on shafts (staffs).

This tool originally came with a wooden stand and forty different stakes, all encased within a glass bell.
Turns, 19th century

A small lathe of this type was called a
turns by clockmakers. The turns was clamped in a vise, with the work mounted on the centers. Power was supplied by a bow whose string wrapped around the workpiece. The worker held a cutting or polishing tool on the tee shaped tool rest with one hand, and moved the bow back and forth with the other to rotate the work. This tool was used for polishing parts, and for cutting gear blanks to size.

Spring Winder, 19th century

Springs had to be specifically designed for different clock parts. They were not produced in standard commercial sizes.

Once a spring had been made, this tool was used to coil it tightly so that it could be inserted into the barrel that held it in the clock.

Cross Peen
Riveting Hammer
19th century
Wood, steel

Utility tool for clock and watch makers. The flat end was for general use, while the chisel-shaped peen end was used for spreading rivet heads. The small size shows the delicacy of the work involved.
This is a "cross peen" hammer because the peen is perpendicular to the handle.

The Museum gratefully acknowledges the assistance of Doug Sinclair, H. C. Bright, and other members of the Horological Tools section of the National Association of Watch and Clock Collectors (NAWCC) in assuring the accuracy of these tool descriptions.

Carla Ojha

©2002 Museum of Early Trades & Crafts