Introduction
The motion works is the dial-side gear system that drives the hands of a mechanical clock. It includes the minute wheel, hour wheel, and cannon pinion. Choosing the wrong size or style causes slipping hands, incorrect timekeeping, or hands that won’t move at all. This guide explains how to choose the correct motion works components for your clock.
Understanding Motion Works Components
Minute wheel
Transfers rotation from the center arbor to the hour wheel.
Hour wheel
Reduces rotation to one revolution every 12 hours.
Cannon pinion
Friction-fitted sleeve that drives the minute hand.
How to Identify the Correct Motion Works Parts
Measure the cannon pinion bore
The bore must match the center arbor diameter for proper friction fit.
Check the minute wheel tooth count
Incorrect tooth count disrupts the gear ratio and causes timing errors.
Measure the hour wheel height
Height must match the dial spacing and hand stack height.
Matching Motion Works to the Movement
Identify the movement manufacturer
Hermle, Urgos, and Kieninger use specific motion works layouts and tooth profiles.
Check the hand shaft length
Incorrect length causes hands to rub or sit too far from the dial.
Match the hand style
Some cannon pinions require specific hand hole sizes or shapes.
Common Motion Works Materials
Brass wheels
Standard for smooth, long-term operation.
Steel cannon pinions
Provide durable friction surfaces for the minute hand.
Alloy wheels
Used in some modern movements for reduced weight.
Common Mistakes When Choosing Motion Works Parts
Incorrect cannon pinion bore
Too loose causes slipping; too tight prevents hand movement.
Wrong minute wheel tooth count
Alters the gear ratio and causes incorrect timekeeping.
Incorrect hour wheel height
Leads to hand interference or misalignment with the dial.
Recommended Internal Links
- How to Choose the Right Clock Hands
- How to Choose the Right Clock Arbors
- How to Choose the Correct Clock Gears & Pinions
- How to Choose the Correct Clock Bushings
FAQs
How do I know which motion works parts my clock needs?
Match the cannon pinion bore, minute wheel tooth count, and hour wheel height to the movement specifications.
Can I mix motion works parts from different brands?
Only if the dimensions and tooth profiles match exactly.
Why do my hands slip when setting the time?
The cannon pinion friction fit may be incorrect or worn.
Why does the hour hand move too fast or too slow?
Likely due to an incorrect minute wheel or hour wheel tooth count.
Can I adjust the friction on a cannon pinion?
Yes, but adjustments must be precise to avoid slipping or binding.
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