Cleaning a Hermle Clock Balance Unit

(dataclaude.ai)

Cleaning a Hermle clock balance unit 

Disassembly and Preparation

Remove the balance unit - The balance assembly typically lifts out as a complete unit on Hermle movements. Note the position of everything before removal, and take photos if needed.

Safety first - Make sure the mainspring is unwound before working on the movement to prevent sudden releases of energy.

Cleaning Process

Disassemble carefully - Remove the balance wheel from the cock (the bridge that holds it). Be extremely careful with the hairspring - it's incredibly delicate and easily damaged. If you're uncomfortable handling the hairspring, consider professional service.

Cleaning solutions:

• Use proper clock cleaning solution (benzine or specialized horological cleaner)
• Avoid harsh chemicals or ultrasonic cleaners on the hairspring
• You can use lighter fluid (naphtha) in a pinch for metal parts

Clean the components:

• Balance wheel - Clean with solution and soft brush, dry thoroughly
• Balance cock/bridge - Clean pivot holes carefully
• Pivots - These are the tiny shafts on the balance staff. Clean gently with peg wood or cloth dampened with cleaner
• Hairspring - If cleaning is necessary, use minimal solution on a soft brush. Many experts recommend leaving the hairspring alone unless visibly dirty

Pivot holes - Use a sharpened peg wood (orangewood sticks work well) to clean out the jewel holes where the balance pivots sit. The holes must be absolutely clean and dry.

Inspection

Check for:

• Bent or damaged pivots
• Hairspring damage (kinks, rust, touching coils)
• Worn jewels or pivot holes
• Balance wheel wobble or damage

Lubrication

Critical step - The balance pivots need proper clock oil:

• Use only proper clock oil (Moebius 9010 or similar thin synthetic oil for balance pivots)
• Apply the tiniest amount to each pivot hole - just a touch
• Never oil the hairspring
• Over-oiling is worse than under-oiling

Reassembly

• Reattach the balance wheel to the cock
• Ensure the hairspring isn't pinched or touching anything
• Reinstall in the movement
• The balance should swing freely with minimal impulse

Important Warnings

Hairspring fragility - This is the most delicate part. Even touching it with your fingers can damage it from oils or bending. Use tweezers only if necessary.

Magnetization - If the hairspring becomes magnetized, the clock won't keep time. Use a demagnetizer if needed.

Beat setting - After cleaning and reassembly, the clock needs to be "in beat" (the tick-tock should be even). This may require adjustment.

When to Seek Professional Help

Consider professional service if:

• The hairspring appears damaged
• You're uncomfortable with the delicate work
• The balance pivots are worn or damaged
• The clock is valuable or antique
• You lack proper tools (jeweler's screwdrivers, pegwood, proper oils)

Hermle movements are quality German mechanisms, so they're worth maintaining properly. A full professional service typically runs $200-400 but ensures the work is done correctly.