Custom Keycaps

Ever wanted to spice up your keyboard/Hackpad/fidget toy/where ever you have a keyboard switch?

Try making your own custom keycaps!
This short guide will go over my process of making custom keycaps for my Highway projects (as well as going over some handy CAD commands)

encoder knob tutorial also included at the end :3

guide by @egg_splats! check out my other keyboard-related projects, the Biblically Accurate Keyboard and the Engipad

FYI, this guide will be using Fusion 360! this guide will also be modeling keycaps for standard MX switches (no low-profile switches, but feel free to take notes/inspiration!)

...but why?

Custom keycaps are a nice way to add some personal flair and ✩ polish ✩ to your keyboard projects aside from the case and PCB. They can be placed anywhere, such as the escape key on a 75% keyboard or on a macro-binded key on a deskside macropad.
Custom keycaps can also help with making a certain theme more cohesive and "complete", such as the custom keycaps with eyes on my biblically accurate keyboard!

ok how do i start

First, open up your CAD software of choice and create a sketch on the bottom plane.

Next, you're going to make the bottom face of your keycap.

Most MX-compatable keycaps use bottom dimensions no bigger than 18mm x 18mm, so we will be using that as well! Go to the "Create" section of the toolbar and select the Rectangle tool. You can use any of the three rectangle tools, but I personally prefer Center Rectangle to keep things centered around the origin.

Next, draw a rectangle with 18mm x 18mm dimensions. You can do this while drawing the rectangle by typing in the numbers and using Tab to switch between side dimensions, or use the Dimensions tool by clicking D, then clicking on the sides of the drawn rectangle.

We will also be adding a fillet to the corners of this profile, since a pointy square honestly looks pretty ugly
To do this, click on the Fillet tool, then click on two touching sides of the square to make a rounded corner, also called a fillet! I used 2mm as the radius, but the choice is up to you!

After you have your base, click "Finish Sketch"! Once we do this, we should have a 18mm x 18mm square sketch with rounded corners.

We will be using the Loft tool to create the general shape of the keycap. This tool essentially connects two sketch profiles that are on different planes by making a smooth transition between the two profiles.

When you look at a regular keycap, you'll typically see the keycap taper, or get smaller, near the top. To mimic this shape, we will be using the Loft tool alongside a smaller sketch profile to create the shape of the keycap.

However, to first do this, we need a new plane to make our sketch on! This can be easily done by using the Offset Plane Construction tool! As the name implies, this tool makes a new plane to draw sketches on that is offset, or extended from, from the original plane.

To make our new and shiny plane, select the Offset Plane tool under Construction and click on the square sketch as our plane. Then, drag the arrow up and down to adjust the height of the plane.
We will be using 10mm for now! Keycap height varies, but most non-low profile caps are around the ~9-10mm range.

Once we have our plane, select "OK".

Now that we have our plane, we can make our second sketch required for the Loft! Select the Sketch tool and the newly created plane to create a new sketch on the plane.
From here, there are many ways to approach making the top profile. Due to the simplicity of the model, we can get away with using a regular old rectangle or circle as our top profile.

(I'll get into my own preferred method involving my goat later in the guide :3)

To make a top profile, draw a circle or rectangle on the sketch plane. The position can vary depending on your preference, but for the sake of the guide, we will be centering the shape on the origin. Set the shape to 15mm on each side or in diameter and click "Finish Sketch".

Once we do that, we should have two sketch different sketch profiles that look like this:

Now, we can use Loft to make our keycap! Select Loft under Create, then click on the two sketch profiles. Once we do that, click "OK" to create the body.

We now have the general shape of our keycap, but currently it's COMPLETELY solid

However, we can fix that by using the Shell Command! This command essentially hollows out a solid with an opening, using a specified wall thickness and a selected face as the opening. Almost all keycaps have an opening on the bottom, so for the Shell command, we will be selecting the bottom face of the solid with the wall thickness set to 1mm.

This should result in our keycap having a large opening in the bottom!

We now have an opening, but if we were to print this out and slap it onto a switch, it wouldn't stay on for long...
This is because there is no feature to hold the switches' stem, or the plus-shaped bit poking out that is pressed!

To do this, we can make a new sketch in the inside of the keycap! Select the bottom side of the hollowed-out keycap as shown, and create a sketch.