How to Build an Escapement for Thin Steel Plates

Grind the metal arm to fit into the steel plate grooves.

Escapements regulate the speed of moving thin steel plates in equipment, such as the ticking gears in grandfather clocks. This escapement consists of a metal arm cut at an angle to fit into the grooves of the gear wheel. As the gear turns, the escapement rises at the gear's exerted force. It lifts over the tooth of the gear and falls into the next groove, keeping the gear moving at a steady pace.

Things You'll Need

• Tape measure
• Paper
• Pencil
• Tape
• Escapement arm
• Tool grinder
• Scissors
• Blank arbor
• Drill
• 10-24 screws

Instructions

1. Measure all the angles of the steel plate groove between the gear teeth. Write down the width and height of the groove along with the angles of the teeth. You can also use a piece of paper to create an outline of the grooves and angles. For example, place the paper against the gear and tape it in place. Hold the gear up against a lighted window so you can see the gear behind the paper. Set the tip of the pencil against the paper at the tip of the gear tooth. Draw the outline of the opening on the paper by following the edge of the gear tooth down into the groove and up the side of the other gear tooth.

2. Mark your measurements onto the face of the escapement arm. If you created an outline of the inside groove between the two gear teeth on a piece of paper, use it as a template for the shape of the escapement arm.

3. Cut out your template with scissors. Tape the paper against the escapement arm. Draw a line along the outside edge of the paper in the shape that will fit between the metal teeth of the steel plate gear.

4. Secure the escapement arm, also known as a fly cutter, on the tool grinder. Push the escapement arm against the grinding wheel, shaping the escapement arm's tip with a slight slant. Move the escapement arm so it faces lengthwise against the grinding wheel to grind the angle on the right side, following the outline shape created by your template.

5. Create a slot in the center of the top of the arbor to hold the escapement arm. Mill a 1/8-inch slot into the top to a depth where the escapement arm fits flush with the top of the arbor. Mill off the left side of the arbor to the same depth of the escapement arm, leaving 1/8-inch wide piece of metal opposite the created slot to hold the screws.

6. Drill two .19-inch holes through the arbor and escapement arm, leaving enough length to the escapement for it to enter the grooves of the gear. Screw in 10-24 screws to secure the escapement arm to the arbor.

7. Place the gear into the equipment where it will turn mechanically. Since the arbor has threads along the open end that is opposite where the escapement is attached, screw the arbor into the base. The base should allow the escapement arm to rock up and down.

8. Lower the escapement arm until it rests in the gear teeth groove. Turn on the equipment as the gear turns, pushing the escapement up the sides of a gear teeth as it falls into the grooves, regulating the gear speed.

References

• Abbeyclock.com: The Origin and Evolution of the Anchor Clock Escapement
• Online Clock Building: Making Clock Escape Wheels with a Fly Cutter