Hot-swap Socket Selector

Working Principle

A hot-swap socket is a small surface-mount clip soldered to the underside of the PCB that grips a switch's contact pin. The dominant family in MX builds is the Kailh MX hot-swap socket, with a low-profile Choc variant for Kailh Choc switches; the two are not interchangeable because the pin spacing and body height differ entirely. Selection depends on three factors. PCB thickness matters because the socket's retention depends on how much of the pin protrudes through the board: standard PCBs are 1.6 mm, and thinner 1.2 mm flex-cut PCBs leave less pin engagement, which makes a socket more likely to lift under repeated swaps. Switch pin gauge matters because thicker or slightly bent pins spread the socket contact and permanently reduce grip. Mounting method matters for repair: sockets are soldered at two pads, and because the mechanical load during a swap is applied directly to those pads, a reflowed socket with insufficient solder fillet will tear away. The practical guidance that follows is consistent: always support the PCB from below when inserting a switch, always align pins before pressing, and when replacing a socket, add a small amount of extra solder to build a stronger fillet. The selector also flags when a build would be better served by soldering directly, which is the case for boards intended to be assembled once and for switches with non-standard pins.

How to Use

1. 01Enter your PCB thickness — read it from the vendor spec or measure with calipers.
2. 02Select the switch family you plan to use.
3. 03Select whether the PCB has flex cuts and how often you expect to swap switches.
4. 04Read the recommended socket family, expected swap durability and the soldering notes for repairs.
5. 05Note: if you expect to swap fewer than twice, soldering is more reliable and cheaper.

FAQ

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