Introduction
The floating balance system used in many Hermle movements is a compact, highly efficient timekeeping regulator. Unlike pendulum clocks, the floating balance uses a torsion-style balance assembly suspended on a thin wire. When properly set up, it provides excellent accuracy and stability. This guide explains how the floating balance works, how to adjust it, how to diagnose common issues, and what to check when servicing Hermle movements such as the 340‑020.
How the Floating Balance System Works
Suspended balance design
The balance wheel is supported by a thin wire rather than a traditional pivot. This reduces friction and allows the balance to oscillate freely.
Impulse and escape interaction
The escape wheel delivers impulse to the balance through a fork and roller system. Proper alignment is essential for consistent amplitude.
Self-centering action
The wire suspension naturally centers the balance, reducing sensitivity to case leveling compared to pendulum clocks.
High beat rate
Floating balance units typically run at a higher beat rate than pendulum clocks, improving accuracy.
Compact footprint
The design allows Hermle to use the same movement in both mantel and wall clocks without requiring pendulum clearance.
Setting Up the Floating Balance
Centering the balance
The balance wheel must sit level and centered. If it leans or drifts, the wire may be twisted or damaged.
Checking the wire
The suspension wire must be straight and free of kinks. Even slight bends affect timing and amplitude.
Positioning the fork
The fork must engage the roller pin cleanly. Too much clearance causes weak impulse; too little causes binding.
Ensuring free rotation
The balance should rotate smoothly with no scraping or rubbing against the movement frame.
Initial beat setting
Beat is set by rotating the entire balance assembly. Small adjustments make significant changes.
Timing and Regulation
Using the rating screw
Turning the rating screw changes the effective length of the balance spring, speeding up or slowing down the clock.
Small adjustments only
Because the balance is sensitive, adjustments should be made in very small increments.
Checking amplitude
Healthy amplitude is essential for accurate timekeeping. Low amplitude indicates friction or power loss.
Testing over 24 hours
After adjustment, allow the clock to run for a full day before making further changes.
Verifying beat symmetry
Even tick and tock spacing ensures the balance is centered and receiving equal impulse.
Common Problems With Floating Balance Movements
Weak or uneven amplitude
Often caused by dirt, dried oil, or worn pivots in the train leading up to the escape wheel.
Balance wobble
A bent or twisted suspension wire causes wobble and poor timekeeping.
Fork misalignment
If the fork is too high or low, the roller pin will not receive proper impulse.
Escape wheel wear
Worn teeth or rough pivots reduce power and cause erratic balance motion.
Power loss from the barrel
Weak mainsprings, dirty barrels, or rough arbor hooks reduce the energy reaching the escapement.
Specific Notes for Hermle 340‑020 Movements
Balance sensitivity
The 340‑020 uses a compact floating balance that is extremely sensitive to dirt and lubrication quality.
Train condition
Any wear in the upper train—especially the escape wheel and fourth wheel—directly affects balance performance.
Barrel and mainspring condition
A tired mainspring or dirty barrel reduces amplitude and causes intermittent stopping.
Fork and roller alignment
The fork must be centered on the roller pin. Even slight misalignment causes flutter or skipping.
Beat adjustment
Beat is set by rotating the balance assembly. The 340‑020 responds quickly to small changes.
Troubleshooting Flowcharts
If the balance barely moves
Check wire → Check fork clearance → Check escape wheel → Check power from barrel
If the clock runs fast or slow
Adjust rating screw → Check wire twist → Verify beat → Check amplitude
If the balance wobbles
Inspect wire → Replace if bent → Check balance seating → Verify fork alignment
Common Mistakes to Avoid
Oiling the wire
The suspension wire must remain clean and dry. Oil causes drag and timing issues.
Bending the wire during handling
Even slight bends affect performance. Handle the balance assembly carefully.
Over-adjusting the rating screw
Large adjustments cause instability. Use small increments only.
Ignoring power issues
The balance cannot compensate for weak power from the train or barrel.
Misaligning the fork
Incorrect fork height or angle causes skipping, flutter, or stopping.
Checklist for Final Verification
• Balance centered and level
• Wire straight and untwisted
• Fork aligned with roller pin
• Amplitude strong and even
• Beat symmetrical
• Movement runs full cycle without stopping
FAQs
Why is the floating balance so sensitive?
The low-friction design amplifies any issues in the train or suspension wire.
Can the suspension wire be replaced?
Yes. Replacement wires must match the original thickness and length.
Does the 340‑020 require special adjustment?
It requires precise beat and fork alignment due to its compact balance design.
Why does the balance flutter?
Usually caused by incorrect fork height or excessive impulse.
How do I know if the balance is healthy?
Strong, even amplitude and stable beat indicate proper operation.
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