A timegrapher gives you three numbers every time you clip a watch onto it: rate, beat error and amplitude. Knowing what those numbers mean, and what a bad reading is trying to tell you, is what turns a timegrapher from a novelty gadget into a genuine diagnostic tool.
This guide builds on our introduction to what a timegrapher tells you and goes further into reading the numbers themselves, so you can work out what to check next rather than just noting that a watch is “off”.
Rate: how fast or slow the watch is really running
Rate is shown in seconds per day (s/d), and it tells you how far ahead or behind the watch will drift over 24 hours if nothing changes. A positive number means the watch is running fast, a negative number means it is running slow.
Most mechanical watches are not expected to be perfect. Many everyday automatics sit somewhere between minus ten and plus ten seconds a day and are considered perfectly serviceable, while higher-grade movements are built to tighter tolerances. What matters more than the exact number is consistency. A rate that jumps around wildly between positions, or that changes a lot after a full wind down, points to a problem rather than simple ageing.
Beat error: how evenly the balance wheel swings
Beat error measures the difference in time between the balance wheel’s swing in one direction and its swing in the other. In a healthy escapement, both swings should take almost exactly the same time. A high beat error means the tick and the tock are uneven, even if the average rate looks acceptable.
Small amounts of beat error, typically under one millisecond depending on the movement, are common and rarely worth chasing. Higher figures are usually a sign of a bent hairspring, a balance that has been knocked, or a hairspring stud that has shifted, and they often explain why a watch sounds slightly “off” even when the timekeeping seems close enough on paper.
Amplitude: how much power is actually reaching the balance
Amplitude is measured in degrees and shows how far the balance wheel swings on each beat. It is the number that tells you the most about the health of the movement as a whole, because it reflects how efficiently power is travelling from the mainspring, through the train, to the balance.
As a rough guide, amplitude in the range of roughly 220 to 280 degrees in the dial-up position on a fully wound watch is typical for many mechanical movements, though the exact healthy range varies by calibre. Low amplitude, especially if it drops sharply as the watch runs down, is one of the most common signs of a movement that needs attention.
What a bad reading is asking you to check
Once you know which number looks wrong, the next step is working out why. A few patterns come up again and again on the bench:
- Low amplitude across all positions: often points to dried out or missing lubrication, or a mainspring that has lost some of its power. This is where checking your oiling with the correct grades, such as those covered in our guide to choosing the right Moebius watch oil, becomes relevant rather than assuming a part needs replacing.
- Rate that swings a lot between dial-up and dial-down: can indicate issues with pivots, a bent staff, or, less often, magnetism affecting the balance and hairspring.
- Sudden rate or amplitude changes with no obvious cause: is worth checking against magnetism before anything else, since a magnetised hairspring can throw numbers off in ways that look like a mechanical fault.
- Amplitude that falls away quickly after winding: suggests the mainspring or barrel is not holding power as it should, rather than a regulation problem.
Reading results consistently
To get numbers you can trust, test the watch in more than one position, typically dial up and dial down as a minimum, and take the reading after the watch has had a full wind rather than partway through a run down. A single reading taken at a random point in the power reserve can be misleading, particularly for amplitude, which naturally falls as the mainspring unwinds.
A reliable multifunction unit such as the Weishi N1000 multifunction timegrapher makes it straightforward to capture rate, beat error and amplitude together, which is what lets you compare positions properly instead of guessing from a single number.
When to stop diagnosing and start servicing
Timegrapher numbers are a starting point, not a full diagnosis. If oiling, demagnetising and basic checks do not bring the rate, beat error and amplitude back into a sensible range together, that is usually the point where a proper strip, clean and reoil is the honest next step rather than continuing to chase a symptom on the surface. Our range of watch oils and silicone greases covers the consumables you need once you get to that stage.
