Pump pushers are chronograph buttons that work the moment you press them, with no need to unscrew them first. They are one of the two main pusher types. They are quicker and more pleasant to use than screw-down pushers, and their clean shape stays close to the look of historic chronographs.
How does a pump pusher differ from a screw-down pusher?
Watch guides split chronograph pushers into two main families: the pump kind and the screw-down kind. A pump pusher works as soon as you press it. A screw-down pusher must be unscrewed before the chronograph can be used. The screw-down design locks the button mechanically, which guards against pressing it by accident. The cost is speed and feel. Screw-down pushers are slower and less pleasant to operate. On Rolex Daytonas with screw-down pushers, the button can be locked shut with a rotating, barrel-shaped mechanism. A pump pusher has no such lock.
How do pump pushers keep water out?
Pushers keep water out with gaskets. These sit around the pusher shaft or inside the tube it slides through. The seal holds, and the button can still move. This is what lets a pump pusher stay ready to use at any moment while still keeping water out. Screw-down pushers are said to have been brought in as an alternative to pump pushers, to make watches more water-resistant.
Where it comes from
Pump pushers are the classic style. They were in use by the 1930s, and most watchmakers still fit them today. Sotheby’s describes them as the standard button-type controls, placed at 2 and 4 o’clock on a chronograph such as the Rolex Daytona. Several vintage Daytona references used them, including the 6239, 6241, 6262 and 6264.
Checked