Fitting a Magnetic Encoder on Ball Shifter

Hey all,

We recently purchased our first 3 Cim Ball Shifter from Vex as well as the SRX Mag Encoder. Anyone have experience on how to mount the encoder to the gearbox?


The 3CIM ball shifter is designed to fit a grayhill encoder rather than a CTR mag encoder

It is probably easiest to mount the mag encoder to an outer axle rather than directly onto the gearbox( this is dependent on having access to a lathe.)

This document show potential installation methods

First we tried printing the bottom half of the shell, but adding legs to make it a single mount and sensor holding setup. Turns out re-making something that someone already made is a waste of time, so we wound up designing a simple little printed “bracket” to mount the mag encoder for our solution.

Here’s an early print of the mag encoder bracket. If you’d like, I can send you the CAD for it. (that print was NASTY. Z-offset wasn’t dialed in, the bed wasn’t quite leveled right, and the temp settings weren’t dialed in yet)

If you have 3D printing ability, it makes mounting these a breeze.

Edit: Here’s the .stl for the mount. The central holes are sized appropriately based off the SRX Mag Encoder housing, and the center hole is large enough to allow spacing of the magnetic plug. Using barely oversized plastic also allows you to align the sensor to the magnetic. Turns out slop can be useful!