Read three numbers — rate, amplitude, beat error — and then read the fourth field, the lift angle. A reading taken at the wrong lift angle is a wrong amplitude wearing a decimal point.
How to read a timing machine
issue ISSUE 01checked 2026-09-16responsible Escapement Papers (a named bench, not a person)
What you need A timing machine or a phone timing app; the movement's lift angle; the watch at a known state of wind; a note of the position being measured.
tape card: the three numbers and the fourth field
| Reading | Healthy range | What it tells you |
|---|---|---|
| Rate | -4 to +6 s/d | The period of the oscillator |
| Amplitude | 250-310 degrees | The health of the train and lubrication |
| Beat error | 0.0-0.6 ms | How evenly the two beats are spaced |
| Lift angle | stated by you | Nothing on its own; it changes the other two |
Steps
- Set the lift angle for the movement before you read anything. If you do not know it, say so and treat the amplitude as unusable.
- Wind the watch fully and let it settle for a few minutes. A reading taken on a half-wound watch measures the mainspring, not the movement.
- Read in the position you care about, and write the position down. Dial up and crown down are not the same watch.
- Read rate first, then amplitude, then beat error. If the amplitude is under about 200 degrees, the rate reading is unreliable and should be repeated after the watch has run.
- Repeat on a second position and compare. A rate that moves with position is a poise or a lever problem, not a regulation problem.
What each number is actually comparing
| Reading | Measured against | Sensitive to |
|---|---|---|
| Rate | The machine's own reference | Oscillator period, regulator setting |
| Amplitude | The beat waveform, via the lift angle | Train health, lubrication, mainspring |
| Beat error | The gap between two successive beats | Fork and roller clearance, banking |
| Lift angle | Nothing — you supply it | Everything about the amplitude figure |
The field nobody sets
Amplitude is not measured directly. The machine times how long the balance takes to cross the lift angle, and divides. If the lift angle you entered is wrong, the amplitude it prints is wrong, and the rate reading can shift slightly as well. Two machines with different default lift angles will disagree about the same watch while both being correct.
The bench holds that a published amplitude without its lift angle is not a measurement, it is a rumour, and that this should be the first question asked about any timing figure quoted online.
References
- Ref 1Measuring Instruments, Horopedia – Watchmaking Encyclopediasupports the instrument class a timing machine belongs to
- Ref 2Quality Testing, Horopedia – Watchmaking Encyclopediasupports the quality-testing framework these readings sit inside
- Ref 3NIST Time and Frequency Publication Databasesupports the published reference material a timing reading is compared against
One link, one document, titled as it titles itself. No home pages, no search results.
Set this page down Set this page down when you have written down the lift angle alongside the three numbers.