The Rolex Microstella Tool


The Microstella is Rolex system to adjust the balance wheel to make sure the watch

keep the COSC standard. To do that there is a special tool to adjust the screws with.


The old tool looks like this and it's oil filled to be a little more exact and stable.

At the backside there is graduation which means 1 second per day for the low type of head nut and 2 seconds for the high type of head nut for each line.

A closer look to the tool.

Here we have a balance wheel with the Microstella screws.

Here is how it works.

A few pics of the tool in action.

The instuctions from Rolex.


And some pics of the new/current Microstella tool.


Photo credit for the new Microstella tool: Tony Axelzon


So lets put up a watch at the timing machine. Not good -17 seconds a day.

So I pull off the bracelet.

With the Ref 2100 tool.

Take place in the case opener.

Off we go.

Let the fun begin

This is a little tricky.

22 minutes later we are close. A little low amplitude so maybe a service will made it perfect in the future.