Guides / Running a Group Buy

Getting a Custom CNC Keyboard Case Made, Start to Finish

September 21, 2026

You have a model you are happy with. Somewhere between that model and a box of anodised cases there is a machine shop, an anodiser, a freight forwarder and about six decisions that will decide whether the run goes well. This is what those decisions look like in order.

Start with what is actually machined

A keyboard is a stack, and only part of that stack comes off a mill. The top case, the bottom case, the plate and the weight are machined from solid. The gasket is die cut. The PCB, the foam and the switches are yours to source. A surprising number of first RFQs describe the whole board and leave the shop guessing about which pieces it is being asked to quote.

Write the machined parts as a list with a quantity next to each one. A shop reading “one 65 percent gasket mount board” has to ask three questions before it can price anything. A shop reading “top case x 180, bottom case x 180, aluminium plate x 180, brass weight x 180” can start work.

Get the files right before you send them

Send a STEP file for each machined part, not an assembly you exported once and never opened again. Send a PDF drawing alongside it. The model tells the shop the geometry, the drawing tells the shop what you care about, and those are different things.

On the drawing, call out the four or five dimensions that matter and let everything else run at a normal block tolerance. On a gasket mount case that usually means the gasket shelf depth, the plate pocket, the screw hole pattern and the USB cutout. A blanket tight tolerance across a whole case raises the price of every feature without making the board better.

Include the PCB outline even though nobody is machining it. The case exists to fit that board, and most of the fitment problems we see trace back to a case designed around a PCB nobody measured.

Name the alloy and the temper

“Aluminium” is not a specification. 6061-T6 and 6063-T5 machine differently, cost differently and, most importantly here, anodise to visibly different colours from the same dye bath. 6063 is softer and lower in silicon, so the colour comes out brighter and more even, which is why colour led designs often specify it. 6061 is stiffer, more available and slightly cheaper to buy. 7075 is stronger again but anodises dark and inconsistently, which makes colour matching across a run harder.

For plates, A5052 is the standard stock in a lot of keyboard drawings and is worth naming directly. Brass C360 is the usual weight material because it machines fast and feels right. Copper C110 looks extraordinary and starts darkening within weeks, so it needs a clear coat and a line in your group buy page explaining that the patina is the point.

Decide the finish, then decide how you will judge it

Machining is the predictable half of the project. The finish is where runs go wrong, because a hundred people will judge the colour under a hundred different desk lamps.

Three things prevent most of the complaints. First, agree a physical golden sample before production, an approved part that defines the colour, the texture and what counts as a defect. Second, insist that the top and bottom halves are anodised in the same batch, because two batches of the same dye will not match closely enough for parts that sit against each other. Third, give the shop a Pantone or RAL reference or post it a sample. A render is not a colour reference and no shop can hit one.

If you want a black or a white that anodising cannot reach, ask about electrophoretic coating instead. It goes on thicker, so check your tight fits before you commit to it.

Ask for a prototype, and use it properly

One prototype, machined and finished the way production will be, is the cheapest insurance in the project. Assemble a full board with it. Put your PCB in it, screw the plate down, type on it and look at it in daylight.

What you are checking is not whether it measures correctly. It is whether the plate drops in without persuasion, whether the daughterboard cutout lines up, whether the gasket compresses the way you wanted and whether the colour is the colour. Those are all cheap to fix once and very expensive to fix a hundred and eighty times.

Understand what the quantity is doing to your price

The per unit price falls sharply between ten units and a hundred, then much more slowly after that. The reason is that setup and finishing have large fixed components. The fixture gets made once. The anodising tank has a batch minimum whether you fill it or not. The first article inspection happens once.

This is why a group buy that hits two hundred units can often be priced meaningfully better than one that hits eighty, and why quoting a single price before you know your number is guesswork. Ask each shop for a price at two or three quantities so you can see the curve before you set your target.

Talk about scrap before it happens

Cosmetic aluminium has a scrap rate. A part that measures perfectly still fails if it has a witness mark on a chamfer or a blemish that survived the blast. Any shop that has run this work will tell you its typical overage. A shop that promises exactly two hundred good cases from two hundred blanks has not made two hundred cosmetic cases.

Agree up front who pays for the overage and what happens to the extras. Many runners sell the spare units, which turns a cost line into a small buffer.

Protect the date

Group buys have public ship dates and people who have already paid. That makes the date part of the specification, not a hope.

Tell the shop the date on the first email. A shop that knows it will tell you honestly whether it can hold it, and an honest no in week one is worth more than a cheerful yes that becomes a six week slip in month three. Ask for the anodiser’s lead time separately, because that is the step most likely to move and the one your shop controls least.

What to send when you are ready

By the time you ask for quotes you should have: STEP files per part, a drawing with real tolerances, the alloy and temper, the finish and a colour reference, the quantity, whether you need a prototype first and the date. That is a package a shop can quote without a second email, and shops quote packages like that faster and more keenly than they quote a paragraph of description.

When it is ready, send it through the RFQ form and we will put it in front of shops that have made cases before.

Frequently asked questions

Keep reading

• The End of US De Minimis and What It Does to a Keyboard Group Buy
• Inspecting a Keyboard Case: Flatness, Rock and Cosmetic Checks