Introduction
The crutch assembly transfers motion from the verge to the pendulum, making it a critical part of the clock’s regulation system. Choosing the wrong crutch leads to poor pendulum swing, stopping, uneven beat, or unstable timekeeping. This guide explains how to choose the correct crutch assembly for your mechanical clock.
Understanding What the Crutch Assembly Does
Transfers impulse to the pendulum
The crutch pushes the pendulum rod, keeping the clock running.
Sets the beat
Proper crutch alignment ensures even tick‑tock spacing.
Connects the verge to the pendulum
The crutch foot must match the pendulum rod style for smooth motion.
How to Identify the Correct Crutch Assembly
Match the crutch length
The length must match the movement’s geometry to avoid over‑ or under‑swing.
Check the foot style
Common styles include loop, fork, friction‑fit, and adjustable feet.
Match the verge arbor size
The crutch must fit the verge arbor securely without wobble.
Matching Crutch Assemblies to the Movement
Identify the movement manufacturer
Hermle, Urgos, and Kieninger use specific crutch lengths and foot styles.
Match the pendulum rod style
Some rods require loop feet; others require fork or friction‑fit designs.
Check verge compatibility
The crutch must align with the verge pallets for proper impulse delivery.
Common Crutch Assembly Materials
Steel crutches
Durable and ideal for long‑term stability.
Brass crutches
Common in antique clocks and lighter movements.
Alloy crutches
Used in modern clocks for reduced friction and wear.
Common Mistakes When Choosing Crutch Assemblies
Incorrect crutch length
Leads to weak pendulum swing or excessive over‑swing.
Wrong foot style
Causes binding, uneven beat, or pendulum stoppage.
Incorrect verge arbor fit
Results in wobble, poor impulse, or unstable timekeeping.
Recommended Internal Links
- How to Choose the Right Clock Verge Assemblies
- How to Choose the Right Pendulum Rods
- How to Choose the Correct Clock Bushings
- How to Test a Clock Train During Reassembly
FAQs
How do I know which crutch assembly my clock needs?
Match the crutch length, foot style, and verge arbor size to the original movement.
Why does my pendulum stop after a few minutes?
Often caused by incorrect crutch length or poor foot‑to‑rod alignment.
Can I adjust a crutch?
Minor adjustments are possible, but excessive bending can weaken the assembly.
Do crutch assemblies from different brands interchange?
Only if the length, foot style, and verge compatibility match exactly.
Why is my clock out of beat?
The crutch may be misaligned or mismatched to the pendulum rod.
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