How to Regulate Your Automatic Watch at Home
Can You Regulate a Watch at Home?
Yes, you can adjust the accuracy of your automatic watch at home with a few simple tools. Regulating a watch means adjusting the balance wheel to make it run faster or slower. It is one of the most satisfying watch modding skills to learn.
Here is how to regulate an NH35 or NH34 movement from Funny Items.
What You Need
- Watch timegrapher app — Download "Toolwatch" or "Watch Tuner" on your phone
- Fine screwdriver — 1.0mm flathead
- Case back opener — To access the movement
- Stable surface — Lay the watch flat, dial up
Step-by-Step Regulation
Step 1: Measure Current Accuracy
Set the watch to an accurate time reference (phone clock, atomic clock website). Wear it for 24 hours, then compare. Note how many seconds it gains or loses per day.
Step 2: Open the Case Back
Use a case back opener to access the movement. Be careful not to touch the balance wheel or hairspring.
Step 3: Find the Regulator
The NH35 has a regulator arm on the balance cock. It is a small lever that controls the effective length of the hairspring. Moving it toward the "+" mark makes the watch run faster. Moving it toward "-" makes it run slower.
Step 4: Adjust in Small Increments
Move the regulator arm very slightly — we are talking fractions of a millimeter. Even a tiny adjustment can change accuracy by 10-20 seconds per day.
Step 5: Test Again
Close the case back and wear the watch for another 24 hours. Compare the new accuracy. Repeat if needed.
What Is Beat Error?
Beat error measures how symmetrical the balance wheel swing is. A high beat error means the watch ticks unevenly. On the NH35, there is a pair of screws on the balance wheel that can adjust beat error — but this is an advanced adjustment best left to experienced modders.
Common Regulation Mistakes
- Adjusting too much — Small changes have big effects. Move the regulator in tiny increments.
- Touching the hairspring — The hairspring is extremely delicate. Never touch it with tools.
- Not testing long enough — One hour is not enough. Test for 24 hours minimum.
- Magnetizing the watch — Keep the watch away from phones, laptops, and magnets during testing.
Frequently Asked Questions
Will regulation void my warranty?
Regulating a watch yourself may void the manufacturer warranty. Practice on a spare movement first.
How accurate can an NH35 get?
With careful regulation, most NH35 movements can achieve +/-10 seconds per day. Some achieve +/-5 seconds.
Should I use a timegrapher?
A professional timegrapher ($300+) gives precise readings. Phone apps are less accurate but good enough for basic regulation.