Hot-swap or soldered PCB

A hot-swap PCB has small metal sockets fitted at the factory instead of switches being soldered directly to the board. Kailh makes most of the sockets you'll find, in separate versions for standard MX switches and for low-profile Choc switches^[1]. The switch pins simply push into the socket and are gripped by spring tension in the contacts, with no solder involved on your side. Boards such as the KBDfans Redux 60 RGB ANSI PCB and KBDfans DZ60RGB-ANSI V2 Hot Swap PCB use this arrangement, which is why switches on them can be pulled and swapped in seconds.

The sockets are gold-plated to resist oxidation and are rated by the manufacturer for a set number of insertions before contact quality starts to fall off, currently around 100 cycles on the sockets most vendors sell^[1]. That is only a count of full removals and reinsertions, not typing, so it comfortably covers years of ordinary switch swapping for most people.

Switch pins come in two counts. A 3-pin switch has two metal legs that carry the signal plus one central plastic locating pin, and depends on a plate to hold it square. A 5-pin switch adds two extra plastic legs either side, which drop into matching holes in the PCB itself and hold the switch steady even on a plate-less build. Cherry sells its MX2A line in both forms, a plate-mount 3-pin version and a PCB-mount 5-pin version^[3], and Cherry MX2A Red and Cherry MX2A Brown are typical examples.

A 3-pin switch fits any MX PCB. Most hot-swap PCBs also have holes for the two extra legs, so 5-pin switches fit too, but some only have the centre hole. If you own 5-pin switches and your PCB is one of those, the two extra plastic legs can be clipped off with flush cutters, but the two metal contacts must never be touched: they carry the keystroke^[4]. Treat clipping as a fallback for switches you already own, not a first plan. Buying the right pin count to start with is simpler, and it leaves the switches undamaged if you ever want to sell them on.

The real risk to a hot-swap socket is not the cycle count, it is inserting a switch with a bent pin. Forcing a bent pin into a socket can tear the whole socket off its solder pad, and with it the copper trace underneath, which is a repair job rather than a quick fix^[2]. Before pushing any switch in, check both metal pins are straight by eye, and pull switches out evenly with a two-pronged puller rather than levering with a fingernail.

• Keychron 2-in-1 Switch and Keycap Puller: a combined switch and keycap puller for hot-swap boards; it will not remove soldered switches.

A soldered PCB has no sockets. Each switch's legs pass through holes in the board and are joined to the copper pads underneath with molten solder. You need a temperature-controlled soldering iron, rosin-core solder, and, for fixing mistakes, either a solder pump or solder wick to lift a joint back off. For through-hole work like keyboard switches, an iron temperature of roughly 320 to 380°C is typical^[5]: hot enough for solder to flow onto the pad and pin within a second or two, without sitting on the joint long enough to damage the switch or lift the pad off the board.

Because desoldering a full board of switches is slow, it is worth doing anything you plan to do to a switch, such as lubing it, before it goes near the iron rather than after.

• Gateron Switch Opener: opens MX-style switch housings in one motion, for lubing before the switches go in.

Soldered PCBs are cheaper to make, since there is no socket part and no extra assembly step, which is one reason plenty of value and office boards are soldered rather than hot-swap. They also suit anyone who already knows which switch they want and has no plan to swap it later. The Leopold FC900R PD is a good example: a wired, soldered full-size board built around consistent quality and internal dampening rather than switch experimentation.

Hot-swap sockets take up more board space than a plain solder pad, and every extra layout option, a split backspace, a stepped Caps Lock, an ISO Enter, needs its own set of pads or sockets wired in. That is one reason solder PCBs usually cover more layouts than a hot-swap board on the same footprint. The GH60 standard itself began as an open community PCB design shared so other designers could build compatible cases and parts around it^[6], and that openness is a large part of why so many alternate 60% PCBs exist today.

The solder-only KBDfans DZ60 Rev 3.0 PCB (now hard to find in stock) supports ANSI and ISO plus around fifteen alternate layouts on one board, where the hot-swap KBDfans Redux 60 RGB ANSI PCB and KBDfans DZ60RGB-ANSI V2 Hot Swap PCB are fixed to a single ANSI layout. The same pattern holds at TKL size: the KBDfans Tofu TKL R2 Wired Solder PCB covers ANSI, ISO, split backspace, split right shift, stepped caps and a 7u bottom row on one board. If you want ISO or another non-standard layout, check the parts pages for a hot-swap PCB built specifically for it, such as the KBDfans Tofu65 3.0 ISO Wired Hotswap PCB; failing that, a solder PCB is usually the only route. The builder flags a layout mismatch before you buy, whichever way you go.