Introduction
The escape wheel arbor supports the escape wheel, allowing it to spin freely and interact correctly with the verge. If the arbor is the wrong size, length, or pivot diameter, the escapement will skip, flutter, bind, or stop entirely. This guide explains how to choose the correct escape wheel arbor for your mechanical clock.
Understanding What the Escape Wheel Arbor Does
Supports the escape wheel
The arbor holds the wheel securely and ensures proper tooth engagement with the verge.
Controls rotational stability
Correct pivot size and finish ensure smooth, low-friction rotation.
Maintains train alignment
The arbor must align with the fourth wheel and verge for proper escapement action.
Key Features of Escape Wheel Arbors
Pivot diameter
The pivot must match the movement’s pivot holes or bushings.
Arbor length
Length determines how the wheel sits between the plates and interacts with the verge.
Wheel mounting fit
The arbor must match the escape wheel’s center hole or press-fit hub.
How to Identify the Correct Escape Wheel Arbor
Match the pivot size
Even slight differences cause friction, wobble, or excessive endshake.
Check the arbor length
Too long causes binding; too short causes disengagement or skipping.
Verify wheel compatibility
The arbor must fit the escape wheel’s hub securely without slippage.
Matching Escape Wheel Arbors to the Movement
Identify the movement manufacturer
Hermle, Urgos, and Kieninger use specific arbor lengths and pivot diameters.
Match the escape wheel
The arbor must align the wheel correctly with the verge pallets.
Check the train ratio
The arbor must maintain proper spacing between the fourth wheel and escape wheel.
Common Escape Wheel Arbor Materials
Steel arbors
Durable and ideal for high-wear escapement components.
Brass arbors
Common in antique clocks and lighter movements.
Hardened alloy arbors
Used in modern clocks for improved wear resistance and precision.
Common Mistakes When Choosing Escape Wheel Arbors
Incorrect pivot diameter
Causes friction, wobble, or binding in the pivot holes.
Wrong arbor length
Leads to skipping, fluttering, or locking failure.
Incompatible wheel fit
The wheel may slip, bind, or sit off-center on the arbor.
Recommended Internal Links
- How to Choose the Right Clock Escape Wheels
- How to Choose the Right Clock Verge Assemblies
- How to Choose the Correct Clock Crutch Assemblies
- How to Choose the Correct Clock Crutch Loops
FAQs
How do I know which escape wheel arbor my clock needs?
Match the pivot size, arbor length, and wheel fit to the original movement specifications.
Why is my escape wheel wobbling?
The arbor pivot may be undersized or the wheel may not be properly fitted.
Can I reuse an old escape wheel arbor?
Only if the pivots are smooth, straight, and within tolerance.
Do arbors from different brands interchange?
Only if the pivot size, length, and wheel fit match exactly.
Why does my clock stop after a few minutes?
Incorrect arbor length or pivot size can cause binding or poor escapement action.
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