Hello readers and MAKEiT owners, and welcome to to the first installment of The First Layer, MAKEiT’s blog section devoted to advanced printing and design-for-print techniques. From the desk of our design director Russell Singer, The First Layer will be your new source for tips and techniques to take your 3D printing ability further.
In today’s post I’m revisiting a project I completed a few weeks back: creating a realistic wood finish for the manual transmission shift knob of my Mini Cooper. Because the shift knob is a regular point of tactile interaction it was important to achieve not only a high quality finish that would appear as wood, but also a comfortable form with enjoyable tactile feedback and functional usability. In this first post I’ll focus on the CAD considerations and the printing process, follow along on the second post for the full finishing technique to achieve the beautiful effect shown below.
Aside from preferences on shift knob weight and profile, the only real functional consideration is getting a snug secure fit on the shifter shaft. After one attempt with a simpler friction-fit design, I found the hot daytime temperatures in Southern California would cause enough size distortion to loosen the knob even though it might be very stuck in place in cooler temperatures. I revised the design to work with set screws and some hex nuts that are enclosed into the print, as shown below: