How to read a timegrapher

Russell Sheldrake

When you first get into this hobby, you likely never thought that it would lead you down this rabbit hole. Yet here you are, trying your best to figure out how to measure exactly how accurate your precious watch is. You’ve officially made it to the deep end, and there’s no going back for you now. So I hope you’re prepared for a rather nerdy, technical, but enlightening explanation of what the various numbers and lines on a timegrapher mean.

And for those who are already deep into this journey, you may have already read Buffy’s excellent article on how to build your own timegrapher if you don’t fancy forking out for the real deal. It just proves that every part and facet of watch collecting can be affordable and accessible, if you’re willing to be a little inventive. But I won’t be doing this explanation alone, I’m recruiting the help of watchmaker and content creator Greg Petronzi, otherwise known as True Patina, who has recently made a wonderfully clear and educational video on the subject, which I’ve embedded further down for you, as I highly recommend you watching it if you’re more of a visual learner.

But first, a quick breakdown of what you are going to see when you turn on your timegrapher. First of all, you’ll see four numbers displayed along the top. These are parameters that the timegrapher is measuring, and are usually in this order – “rate”, “amplitude”, “beat error”, and “parameters” (also referred to as the beat rate).

The overall goal of adjusting a watch is to try and get that first number, the rate, as close to 0.0 seconds per day (s/d) as possible. Obviously, getting exactly 0.0 is next to impossible, but you should be able to get it close enough to round down to it. The more accurate your watch is, the closer that number should be, as this is the number that tells you how much time your watch is losing or gaining every day. You would have likely heard about COSC certification, which requires a watch to be within -4/+6 s/d when it leaves the manufacture, with other chronometer certification guidelines sometimes requiring event stricter standards.

The next number you need to worry about is the beat error. Measured in milliseconds, this is going to tell you if the balance wheel is swinging more one way than the other. In other terms, the amount of time between “tick” and “tock”, and then “tick” again. If this number is high, then it likely means the balance wheel itself isn’t balanced and needs some adjustment, or the balance spring isn’t in great condition.

Finally, the amplitude tells you how big each of those swings the balance wheel takes is. This shows how efficiently power is being transferred from the mainspring to the balance, so if your lubricants on the gear train are starting to clog up, the amplitude could dip, causing the watch to run slow.

Underneath these numbers you will see a line, or maybe two, and the aim here is to get it as close to perfectly horizontal as possible. If you see this line straying up or down drastically, I would suggest consulting your local watchmaker. Making adjustments to your precious timepiece with untrained hands can be more risky than you know, though it is possible.

When using the timegrapher, you need to measure the watch in multiple positions, these are the same as when you see that a movement has been adjusted to X number of positions. The standard six positions are crystal up, crystal down, crown up, crown down, crown left, and crown right. You’ll want to measure you watch in all six positions to give yourself a fully accurate average, so that you have an idea of how it performs throughout the day while it’s on your wrist.

Now you’ve read through my explanation, watch the professional, Petronzi, talk you through it in more detail. It also seems like he might be starting a series on this, so it will be worth checking back in with him again to see how he gets on.