Introduction
The Hermle 340‑020 is one of the most common Westminster chime movements, but its chime and strike trains must be set up precisely for correct operation. Proper alignment ensures the chime sequence plays in order, the strike count matches the hour, and the movement transitions smoothly between warning and release. This guide explains how to set up the chime and strike trains, how to position the warning wheel and stop cam, and how to verify correct hammer sequencing.
Preparing the Movement for Setup
Stabilizing the movement
Secure the movement on a stable support so both hands are free. A movement stand makes alignment easier and prevents accidental shifting.
Removing front components
Before setting up the chime and strike trains, remove the chime idler wheel, chime lock plate, chime stop cam, hour pipe/snail, minute wheel, and gathering pallet. This provides clear access to the warning wheels and stop cams.
Inspecting pivots and levers
Check that all pivots rotate freely and that levers move without binding. Any friction will affect warning and release timing.
Checking lubrication points
Apply fresh oil only to the pivots. Do not oil the chime or strike levers, as they must move crisply without drag.
Confirming train freedom
Spin each train lightly to ensure smooth rotation before beginning setup.
Setting Up the Chime Train
Positioning the warning wheel
The chime 5th wheel is the warning wheel. Rotate it until the warning pin aligns with the fly. This provides approximately 90 degrees of rotation during warning.
Holding the wheel in place
Keep a finger on the warning wheel to prevent it from rotating out of position during assembly.
Installing the stop cam
Install the stop cam on the extended arbor just below the warning wheel. The stop cam must be positioned so the chime train stops with the warning pin close to the fly pinion.
Securing the cam
Ensure the stop cam is tight on the arbor. A loose cam causes inconsistent stopping and erratic chime behavior.
Reinstalling the chime components
Reinstall the chime idler wheel, lock plate, and stop cam components once the warning wheel and stop cam are correctly aligned.
Setting Up the Strike Train
Positioning the strike warning wheel
Rotate the strike warning wheel until its warning pin is positioned for proper warning run. The pin should be close to the fly when the train is stopped.
Installing the strike stop cam
Place the stop cam on the strike warning arbor so the train stops cleanly at the end of the strike sequence.
Aligning the gathering pallet
Install the gathering pallet so it begins lifting the rack teeth immediately after release. Incorrect alignment causes miscounts.
Checking rack and snail interaction
Advance the minute hand manually to verify that the rack drops correctly and the snail steps match the hour.
Testing strike release
Ensure the strike enters warning before release and that the hammer sequence is smooth and consistent.
Final Chime and Strike Synchronization
Testing the quarter chimes
Advance the minute hand through each quarter. The chime should play the correct Westminster sequence at 15, 30, 45, and 60 minutes.
Checking hour strike
At the top of the hour, the chime must complete before the strike begins. The strike count must match the hour.
Adjusting hammer lift
Ensure each hammer lifts evenly and returns freely. Bent or dragging hammers cause weak or uneven chimes.
Verifying stop positions
Both chime and strike trains must stop with their warning pins near the fly pinion for consistent warning run.
Running a full cycle test
Allow the movement to run through several hours to confirm stable operation.
Troubleshooting Flowcharts
If the chime sequence is incorrect
Check lock plate → Check stop cam → Check warning wheel → Verify hammer order
If the strike miscounts
Check rack drop → Check snail position → Check gathering pallet → Check warning pin
If the chime stalls
Check fly freedom → Check stop cam tightness → Check pivot lubrication → Check hammer drag
If the strike starts before the chime finishes
Check chime stop cam → Check warning alignment → Verify minute hand position
If the chime runs continuously
Check lock plate → Check stop cam → Check warning pin → Check lever alignment
Common Mistakes to Avoid
Misaligning the warning wheel
Incorrect warning pin position causes erratic chime and strike behavior.
Leaving the stop cam loose
A loose cam causes inconsistent stopping and unpredictable operation.
Oiling levers
Levers must run dry. Oil causes sluggish movement and delayed release.
Incorrect hammer spacing
Hammers must clear each other and the rods for proper tone and sequence.
Skipping full-cycle testing
Testing only one hour may miss timing or sequencing issues.
Checklist for Final Verification
• Warning wheels aligned
• Stop cams tight and correctly positioned
• Chime sequence correct at all quarters
• Strike count matches the hour
• Hammers lift and return freely
• Movement runs full cycle without errors
FAQs
Why must the warning pin be near the fly?
This ensures a consistent warning run and prevents premature release.
Why does the chime stop early?
A loose stop cam or misaligned lock plate interrupts the sequence.
Should the chime and strike levers be oiled?
No. Only pivots receive oil; levers must remain dry.
Why does the strike miscount?
Incorrect rack drop or gathering pallet alignment is usually the cause.
Does the 340‑020 require special setup?
Yes. Its compact design makes warning wheel and stop cam alignment especially critical.
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