Introduction
Installing bushings using hand tools is a core skill in mechanical clock repair. Worn pivot holes cause power loss, stopping, and erratic timekeeping. This guide explains how to install bushings using traditional hand methods while maintaining proper plate geometry, 2nd wheel alignment, and verge interaction.
Understanding Bushing Requirements
Why bushings are needed
Wear in the plate causes the pivot to run off-center, increasing friction and reducing power. Installing a bushing restores the pivot to its original position.
Identifying worn pivot holes
Oval holes, excessive side shake, and visible pivot drift indicate the need for a bushing.
Maintaining plate geometry
The new bushing must be installed exactly where the original pivot center was located to preserve gear mesh and train alignment.
Effect on the 2nd wheel
The 2nd wheel is especially sensitive to alignment errors. Even slight misplacement affects depthing and power transfer.
Effect on the verge
Incorrect bushing placement can alter verge and escape wheel interaction, causing beat issues or locking problems.
Symptoms of Poor Bushing Alignment
Train binds or stalls
Misaligned bushings cause gears to mesh too deeply or too shallowly.
Clock loses power
Increased friction from improper pivot centering reduces efficiency.
Escape wheel flutter or hesitation
Verge interaction becomes unstable when upstream wheels are misaligned.
Clock stops intermittently
Uneven pivot loading causes inconsistent operation.
Beat becomes unstable
Verge geometry shifts when the escape wheel pivot is not centered correctly.
Preparing for Bushing Installation
Marking the original pivot center
Use the unworn portion of the pivot hole to determine the true center. This ensures correct gear depthing.
Supporting the plate
The plate must be supported firmly to prevent distortion during reaming or broaching.
Selecting the correct bushing
Choose a bushing with an outer diameter large enough to remove all wear and an inner diameter slightly undersized for broaching.
Protecting the 2nd wheel pivot
Ensure the pivot is clean and straight before fitting the new bushing.
Maintaining verge alignment
Any bushing work near the escape wheel must preserve the original verge-to-escape geometry.
How to Install a Bushing Using Hand Tools
Step 1: Locate the true center
Use the unworn edge of the pivot hole to determine the original center. This is critical for proper gear mesh.
Step 2: Ream or broach the worn hole
Enlarge the hole evenly until it matches the outer diameter of the selected bushing.
Step 3: Press or tap in the bushing
Install the bushing flush with the plate surface. Avoid tilting or deforming the plate.
Step 4: Broach the inner diameter
Broach the bushing to match the pivot. The pivot should spin freely with minimal side shake.
Step 5: Burnish the pivot hole
Burnishing smooths the bushing surface and improves long-term wear resistance.
Step 6: Verify 2nd wheel alignment
Ensure the 2nd wheel meshes correctly with the pinion above and the wheel below.
Step 7: Confirm verge and escape wheel interaction
Check for proper lock, drop, and impulse. Misalignment indicates the bushing is off-center.
Troubleshooting Flowcharts
If the train binds
Check bushing center → Check depthing → Check pivot freedom → Check plate distortion
If the escape wheel hesitates
Check verge lock → Check escape pivot bushing → Check 2nd wheel alignment
If the clock loses power
Check pivot fit → Check bushing broach → Check gear mesh → Check plate flatness
Common Mistakes to Avoid
Re-centering based on the worn hole
Always use the unworn edge to find the true center.
Over-broaching the bushing
Excessive clearance causes power loss and premature wear.
Tilting the bushing
A tilted bushing misaligns the pivot and increases friction.
Ignoring verge geometry
Escape wheel bushings must preserve original lock and drop.
Distorting the plate
Improper support during reaming can warp the plate.
Checklist for Final Verification
• Pivot centered in original location
• Smooth pivot rotation
• Correct 2nd wheel depthing
• Proper verge lock and drop
• No plate distortion
• Train runs freely under minimal power
FAQs
Why does my clock bind after installing a bushing?
The bushing may not be centered on the original pivot location.
Why is the escape wheel fluttering?
Incorrect bushing placement is affecting verge lock and drop.
Why does the 2nd wheel seem tight?
Depthing changed due to misalignment during bushing installation.
Why does the clock lose power after bushing work?
Excessive pivot clearance or improper broaching increases friction.
Why is the beat unstable after installing a bushing?
Escape wheel pivot alignment affects verge geometry and beat consistency.
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