Introduction
Morbier (Comtoise) clocks use a simple but effective friction clutch to allow the minute hand to advance smoothly while still permitting manual setting. When the hand slips, binds, or feels too loose, the issue is usually in the tension washer, hand collet, or cannon‑pinion friction. This guide explains how the system works and how to diagnose and correct common problems.
How the Morbier Minute‑Hand Clutch Works
Friction‑based system
The minute hand is driven by friction between the cannon pinion and a tension washer or spring.
Hand collet engagement
The hand collet must grip firmly enough to advance the hand but still allow manual setting.
Tension washer function
The washer provides controlled pressure to maintain proper friction.
Hour‑hand tube interaction
The hour hand rides on a separate tube and is not directly involved in clutch tension.
Strike‑train independence
Minute‑hand clutch issues do not affect the strike train, but poor timing can cause misalignment.
Common Minute‑Hand Problems
Hand slips backward
Indicates insufficient friction in the clutch or a weak tension washer.
Hand too stiff to turn
Washer bent too tightly or collet binding on the cannon pinion.
Hand moves inconsistently
Uneven friction or dirt between the friction surfaces.
Hand drifts out of alignment
Collet not seated properly or washer tension uneven.
Minute hand stalls while clock runs
Severe friction loss or worn cannon‑pinion surfaces.
How to Diagnose the Issue
Check hand collet fit
The collet should slide on firmly but not wobble.
Inspect the tension washer
Look for distortion, cracks, or loss of springiness.
Test friction manually
Turn the minute hand gently—should move smoothly with moderate resistance.
Check for dirt or oil
Oil on the friction surfaces destroys clutch action.
Verify cannon‑pinion condition
Worn or polished surfaces reduce friction and cause slipping.
Correcting the Problem
Step 1: Clean friction surfaces
Remove all oil—these parts must run dry for proper clutch action.
Step 2: Adjust the tension washer
Bend slightly to increase or decrease pressure; small adjustments only.
Step 3: Tighten the hand collet
Close the collet slightly if it is too loose on the cannon pinion.
Step 4: Correct worn surfaces
Lightly roughen polished areas with fine abrasive to restore friction.
Step 5: Reassemble and test
Advance the hand through a full hour to confirm smooth, consistent motion.
Troubleshooting Flowcharts
If the hand slips backward
Washer weak → Collet loose → Cannon pinion polished → Friction surfaces oily
If the hand is too stiff
Washer too tight → Collet binding → Dirt in collet → Cannon pinion burr
If the hand moves erratically
Uneven washer tension → Dirt → Collet misaligned → Worn friction surfaces
If the hand won’t stay aligned
Collet loose → Washer uneven → Cannon pinion worn → Hand hole oversized
If the hand stalls
Severe friction loss → Washer collapsed → Collet slipping → Cannon pinion worn
Common Mistakes to Avoid
Oiling the clutch
Oil destroys friction—these parts must remain dry.
Over‑bending the washer
Too much tension causes binding and hand stiffness.
Forcing the hand
Can distort the collet or damage the cannon pinion.
Ignoring wear
Worn friction surfaces must be corrected for reliable operation.
Testing only at the quarter hour
Always test through a full hour to confirm proper behavior.
Checklist for Final Verification
• Hand moves smoothly with proper resistance
• Washer tension correct
• Collet secure
• Cannon pinion clean and dry
• No slipping or binding
• Movement keeps correct minute progression
FAQs
Why does my minute hand slip?
Usually due to weak washer tension or oily friction surfaces.
Should the clutch be oiled?
No—these parts must run dry.
Why is the hand hard to turn?
The washer is too tight or the collet is binding.
Can the washer be reshaped?
Yes—small adjustments restore proper tension.
Is this common in Morbier clocks?
Yes—washer fatigue and collet looseness are frequent issues in antique examples.
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