A DIY mechanical keyboard kit lets you choose every part of the board yourself, but only if those parts fit together. A hot-swap barebones kit covers the core hardware, while a finished build also depends on UK ISO fit, matched switches and plate, working firmware, careful assembly and a landed cost in GBP.
What a hot-swap barebones kit includes
A barebones kit is the core of a custom keyboard, not a finished one. Knowing where the kit stops shows what the rest of the budget has to cover.
What the kit supplies
A custom mechanical keyboard normally has six parts: a case, a PCB, a plate, stabilisers, switches and keycaps. The PCB is the circuit board that registers each key. A keyboard building kit usually covers the case, PCB, plate and mounting hardware. Some kits also add foam, gaskets or stabilizers.
No single standard defines what a barebones kit contains. As a result, the included-items list for the exact kit shows whether stabilisers, foam, a USB cable or firmware come in the box. That list matters more than the product family name.
What you still need
Switches and keycaps are normally left out of a DIY keyboard kit, and you have to choose both before assembly starts. Stabilisers sit under Space, Enter and Shift. Some kits include them, and others only state the mounting type and sizes you need. A hot-swap PCB takes each switch through a socket, so you don't need a soldering iron. The case for a first custom keyboard build is flexibility, not a lower price: a US-priced guide puts builds at about $100 to $400 or more.
Price a keyboard kit in GBP
From there, compare every mechanical keyboard kit on its landed GBP total: the product price plus delivery, VAT and any import charges. Converting a seller's US-dollar headline price leaves those costs out. For goods sold to UK customers at £135 or less, VAT is generally charged at the point of sale.
Above £135, import VAT is collected when the goods arrive, and customs duty may also apply. International deliveries can also carry a carrier handling charge. The UK Trade Tariff service shows how a commodity code is treated, so you can check the charges before you purchase instead of assuming the advertised price covers everything.
Choose a UK ISO layout
Once the budget is set, layout comes next. The layout decides how many switches and keycaps you need, which stabiliser sizes you need and which keycap sets will fit.
Compare mechanical keyboard sizes
Choose the form factor based on the keys you use and the desk space you have. Krome Keyboards offers barebones kits in 65%, 75%, TKL and full-size formats, from compact boards to boards with a number pad.
- 65%: keeps dedicated arrow keys but drops the function row and navigation cluster.
- 75%: adds a function row above the main keys, with no numpad.
- TKL: keeps the function row, arrows and navigation cluster, and drops only the numpad.
- Full-size: includes every key group, numpad included.
Each step up in size adds keys, so a mechanical keyboard's parts list grows with it.
| ISO layout | Keys | F-row | Arrows | Numpad |
| 65% | About 68 | No | Yes | No |
| 75% | About 84 | Yes | Yes | No |
| TKL | 88 | Yes | Yes | No |
| Full-size | 105 | Yes | Yes | Yes |
Verify the ISO hardware
Key count alone doesn't confirm a UK fit. ISO is a physical layout family, while "UK" refers to the regional legends and key assignments. ANSI and ISO differ at the tall Enter key and the shorter left Shift. As a result, an ANSI-only keyboard kit can't become UK ISO through remapping or new legends.
The UK ISO check covers the PCB layout, support from the exact keyboard case and plate, stabiliser positions, bottom-row widths and spacebar size. In QMK's layout representation, ISO Enter measures 1.25u by 2u. That's why matching the physical shape matters more than the total number of keys.
Find matching UK keycaps
Once the hardware is confirmed, turn to keycaps. A genuine UK ISO keycap set includes the tall ISO Enter, the shorter left Shift, normally a 6.25u spacebar and a £ key. An ANSI set can't be assumed to include them.
Even with the right keycaps fitted, the characters depend on two more checks: the firmware keymap and the operating system's English (UK) input setting. The operating system decides whether a key code produces £ or @.
For a first build, choose the UK ISO keycap set first, then the PCB and case. There are fewer UK ISO sets to choose from, and bottom-row fit varies from board to board.
Match switches for no-solder compatibility
With the layout settled, switches come next. Hot-swap removes the need to solder, but it doesn't make every switch fit every board.
Check PCB socket support
Check the PCB socket specification, the plate and the switch type together. MX-style switches come with 3 or 5 pins, and the two extra legs on 5-pin versions help locate the switch. Many conventional hot-swap PCBs accept both. MX-style, low-profile and Hall Effect switches are separate systems, so the PCB has to be designed for the one you choose.
Within the MX-style family, feel is what separates the types. Linear switches move smoothly all the way down. Tactile switches add a bump without extra sound, and clicky switches pair the bump with an audible click.
Pair the plate case and mount
The plate holds each switch housing in line, and it has to match both the PCB layout and the switch technology. An ANSI 60% plate can't be assumed to fit an ISO PCB. Aluminium and FR4 plates are balanced options, and brass is stiffer. POM and polycarbonate plates are usually softer and sound deeper.
The mount decides how the plate sits in the case. A top mount fixes the plate to the upper case, and a gasket mount cushions the assembly from the case. A tray mount uses internal standoffs and is common in lower-cost cases. Plate-mounted, PCB-mounted and screw-in stabs aren't interchangeable: matching them to the PCB holes stops large keys from binding.
Assess Hall Effect platforms
Hall Effect keyboards sense key presses through a magnetic field, not through metal contacts closing. A magnetic switch may fit into a standard socket, but it sends no input without a Hall sensor, a dedicated controller and compatible firmware at each key. The Krome Keyboard Builder starts from Hall Effect boards made by partner brands. It then lets you choose magnetic switches, PBT keycaps, keycap profile and layout, and it flags incompatible combinations.
One base in the builder is the AKKO MOD68 HE ISO, a 65% ISO board with a CNC aluminium case, a gasket mount and a wired USB-C connection. It polls at 8,000Hz and scans at 16,000Hz. Actuation is adjustable from 0.100mm to 3.400mm. The board doesn't support traditional mechanical switches, and other mainstream magnetic switches need to be selected in its Web & Cloud Driver and then calibrated. Officially supported switches reach 0.01mm precision after calibration, and a ready-built compact Hall Effect alternative is the Project Blue ISO 65 Hall Effect keyboard.
Configure firmware support
Once the hardware fits, the firmware decides what each key does. Firmware compatibility needs its own checks, separate from the physical ones above.
Decide between VIA and QMK
VIA lets you remap a compatible QMK keyboard through a graphical interface: keys, layers, macros and supported lighting, with no need to rebuild the firmware. QMK is the open-source firmware that runs on the board itself.
A QMK-compatible PCB doesn't automatically work with VIA. VIA also needs the correct definition file describing the board's physical layout and electrical matrix, so the two are separate claims to check.
On 25 August 2024, VIA-enabled keymaps moved from the main QMK repository to VIA's external QMK userspace. VIA's web app is now the supported way to use current features, and the desktop app is deprecated.
Check support before purchase
Before you buy, confirm support for the exact PCB revision, whether the board is wired or wireless, its physical layout and how it can be recovered or flashed. Support for a similarly named model doesn't count.
The same applies to QMK Configurator, QMK's online keymap tool. It needs the exact keyboard, version and a compatible layout, and QMK compatibility alone doesn't guarantee a board is listed there.
Loading a VIA definition made for a similarly named keyboard can map keys wrongly even though the board still works electrically. That kind of fault undermines customisation and the keyboard experience of the finished build.
Flash safely when needed
When a full firmware change is needed, the QMK workflow identifies the exact keyboard target, creates or edits a keymap, compiles it with qmk compile and installs it with qmk flash. The board has to be in bootloader or DFU mode, and flashing must not be interrupted.
Remapping a key in VIA is a different operation from replacing the firmware. Use VIA for supported remapping, and flash only firmware meant for your exact PCB and layout. Test every key afterwards.
Kit assembly
With the parts confirmed, it is time to build a keyboard. A hot-swap assembly follows a set order, from testing the PCB to fitting the keycaps.
Prepare tools and test the PCB
If you want to build a custom keyboard without soldering, you need a small tool kit rather than a soldering iron:
- Precision screwdriver set: for the different screws used in the case.
- Tweezers and a switch puller: to bridge the contacts during the PCB test and to remove switches, alongside a keycap puller.
- Switch opener, lubricant and brushes: useful if you plan on lubing switches and stabilisers.
Before installing anything, connect the PCB and open a key-testing tool. Bridge each switch position with tweezers to confirm every contact registers while the board is still easy to reach. Sort the screws first, because some kits use specific screws in particular spots.
Install stabilisers and switches
Lubricate and fit the stabilisers before the switches, because they're hard to remove later. Test a stabilised key with a switch and keycap to check for rattle. On a hot-swap board, push each switch straight through the plate into its socket, supporting the socket from below with a finger or desk pad. Straighten any bent pins with tweezers first.
A soldered PCB is different: each switch must sit flush against the board before soldering. For a gasket-mounted kit, fit the gaskets first, then the daughterboard, the cable and any foam. After that, seat the PCB-and-plate assembly and close the case without overtightening the screws.
Finish and diagnose faults
Fit the keycaps last with gentle pressure, checking the unusual sizes: ISO Enter, left Shift, Space and the bottom row. Then test every key, modifier, stabilised key, Fn layer, remap, macro, lighting function and the USB connection. If a key fails, check switch seating, bent pins and the socket, or the solder joint on a soldered board, before you suspect the PCB or firmware.
A Hall Effect board has its own commissioning order: assemble, connect, update the firmware or driver if needed, calibrate, test, set the actuation point and test again. When building your keyboard on a Hall Effect base, recalibration is mandatory after any switch is replaced, before the board is used.
Frequently Asked Questions
What is the main advantage of building my own keyboard from a kit rather than buying a pre-built one?
You choose each part separately: the layout, switch type, keycap profile and plate mounting style. A pre-built keyboard fixes most of these choices at the factory. If one component fails on a self-built board, you replace only that part rather than the whole keyboard.
Can Krome Keyboards assemble my custom keyboard for me, and how long does it take?
Yes. The Krome Keyboards keyboard configurator flags incompatible combinations as you choose parts, and professional assembly is available if you'd rather not build the board yourself. The estimated build time is 11 to 13 working days. The box contains the keyboard, a keycap and switch puller, a USB-A to USB-C cable and a manual.
What is the difference between in-stock, pre-order and group buy keyboard kits?
They are different ways of selling a kit, with different availability and risk. They don't indicate keyboard quality. Group buy extras are leftover stock from a group buy, while prototype pre-order extras are non-final or limited production versions. UK retailers carry large in-stock ranges of kits and keycaps alongside group buys and pre-orders.