Introduction
When the hands on a New Haven clock fail to move—or move only when pushed—the issue is almost always a slipping clutch in the motion works. This clutch provides the friction needed for the minute hand to advance while still allowing manual setting. If it becomes loose, worn, or contaminated, the hands will not track the movement. This guide explains how to diagnose the problem, how the clutch system works, and how to restore proper friction.
How the New Haven Clutch System Works
Friction-based design
The clutch relies on controlled friction between the cannon pinion and the minute-hand bushing.
Allows hand setting
The clutch must slip when the user sets the time but hold firmly during normal operation.
Common failure points
Wear, dirt, dried oil, or a loose tension washer can cause the clutch to lose grip.
Symptoms of a slipping clutch
The hands do not move, move intermittently, or rotate freely with almost no resistance.
Why the movement still ticks
The time train may run normally even when the hands fail to advance.
Diagnosing the Clutch Issue
Check hand resistance
Rotate the minute hand gently. If it spins too freely, the clutch is slipping.
Inspect the hand bushing
Look for looseness or wear where the hand attaches to the arbor.
Test cannon pinion friction
There should be firm but smooth resistance when turning the cannon pinion.
Check for contamination
Oil or dirt on the clutch surfaces reduces friction dramatically.
Verify motion-works engagement
Ensure the minute wheel and intermediate wheels mesh correctly.
How to Repair a Slipping Clutch
Step 1: Remove the hands and dial
This exposes the motion works and clutch components.
Step 2: Clean the clutch surfaces
Remove old oil and residue that may be causing slippage.
Step 3: Tighten the clutch
Gently compress the tension washer or adjust the clutch spring to restore proper friction.
Step 4: Inspect the cannon pinion
Ensure it is not cracked, worn, or loose on its arbor.
Step 5: Reassemble and test
Advance the hands through several hours to confirm proper operation.
Troubleshooting Flowcharts
If the hands still don’t move
Check clutch tension → Check cannon pinion → Check motion works → Check hand bushing
If the hands bind
Check dial clearance → Check hand shape → Check hand nut tension
If the clock stops after reassembly
Check pendulum alignment → Check beat → Check motion-works interference
If the minute hand drifts
Clutch too loose → Bushing worn → Cannon pinion slipping
If the clutch is too tight
Hands hard to set → Excess friction → Risk of bending arbors
Common Mistakes to Avoid
Adding oil to the clutch
Oil destroys friction and makes the problem worse.
Over-tightening the hand nut
This can lock the motion works and stop the clock.
Bending the hand bushing
Excess force can deform the hand and cause binding.
Ignoring worn motion-works gears
Wear can mimic clutch failure and must be addressed.
Reassembling without testing
Always test hand advancement before reinstalling the dial.
Checklist for Final Verification
• Clutch tension correct
• Cannon pinion secure
• Hands advance smoothly
• No dial or hand interference
• Movement runs full duration
• Timekeeping stable
FAQs
Why do the hands move freely but the clock runs?
The clutch is slipping and not transferring motion from the train to the hands.
Can the clutch be repaired without removing the movement?
Often yes, but full access may require dial removal.
Should the clutch be lubricated?
No—friction surfaces must remain clean and dry.
What if tightening the clutch doesn’t help?
The cannon pinion or hand bushing may be worn.
Is this a common issue with New Haven clocks?
Yes—many models use friction clutches that loosen over time.
0 comments