Reddit reviews Kutzall Original Sphere Rotary Burr 1/8" Shaft, Coarse - Woodworking Attachment for Dremel, Foredom, DeWalt, Milwaukee Tools. Abrasive Tungsten Carbide Coating, 3/8" (9.5mm) Head Diameter, S-38-E
We found 1 Reddit comments about Kutzall Original Sphere Rotary Burr 1/8" Shaft, Coarse - Woodworking Attachment for Dremel, Foredom, DeWalt, Milwaukee Tools. Abrasive Tungsten Carbide Coating, 3/8" (9.5mm) Head Diameter, S-38-E. Here are the top ones, ranked by their Reddit score.
Rapid material removal saves you time and effort, letting you focus on the task at hand.Tungsten Carbide teeth give you outstanding wear-life for a much longer lasting burr.Comfortable, effortless operation allows you to easily and quickly remove a variety of materials.Coarse coating provides fast stock removal while leaving a relatively smooth finish.Should only be used on non-metals or non-metallic materials.
I've had a lot of people ask for a build video but if you check out my 15 second typing video in this thread you'll see my video production is really lacking. Given the whole process is 2-3 hours, that's also a pretty long video.
But to answer your direct question, I definitely sculpt the key into its external shape first. I tried the other way around when I first started and quickly gave up.
It might seem like it would be easy to cut too far but this didn't happen once when I switched to walnut.
What worked really well was doing most of the hollowing using the sphere bit in the link below. This handles 75% of the hollowing out and it does so in a very predictable spherical shape.
Problem is, the interior of a Cherry MX keycap isn't spherical. So I then used a reverse code bit square out the interior, this left the walls of the keycap about 1-1.5mm in thickness, which leaves enough room for the switch.
Sphere:
https://www.amazon.com/dp/B0037MI5RI/ref=twister_B07CRQ7LLL?_encoding=UTF8&psc=1
Reverse cone (far right in the picture):
https://www.amazon.com/DRILLPRO-Double-Carbide-Rotary-SizeTungsten/dp/B06W9JFW66/ref=sr_1_1?ie=UTF8&qid=1536972165&sr=8-1&keywords=reverse+cone+rotary+bit