DIY tool setter project for Masso G3

While waiting for the opportunity (space) to set up my Woodworker, I have been working on a few projects, and testing some functionality of my Masso G3 controller.

I wanted to test the auto tool zero function of Masso, so decided to build a prototype tool setter. Those online are often out of my price range, or of questionable/unknown quality. I based it on the work of “Woody” at

I first learned, built, and tested his circuit, and added a blue LED to indicate when the Hall effect sensor is triggered by the lowering tool. Once that was working, I designed and 3D printed a housing for the sensor. I was able to purchase simple materials from common online and local sources, then assembled the tool setter for testing. I designed it using F360, with the goal of learning the CAM required to mill the parts from aluminum and cast acrylic.

Masso makes it very easy to set up a variety of useful functions such as the auto tool zero, work offsets, parking, etc… and I look forward to using these in real life milling soon.

The initial tests of this (crude plastic) prototype are promising. I used a blank rod as a tool, then set it up as three different named tools (A, B, and C). Using MDI commands I switched between tools, and had each tool travel to the same arbitrary location (X450Y70) and go to Z0 there. I had my dial indicator set up to indicate the bottom of the rod as it zeroed.

Because the three tools were actually the same tool, I was looking to see how repeatable the tool offsets were for the tools. I switched between all three tools a total of three times. Looking at the tool offset DRO, the difference ranged from a low of 0.00125mm to a high of 0.006mm.
The dial indicator (with 0.01mm increments), read within the 0.01 increment when the tools were zeroed. I then had time to repeat the test by changing the tool length of each tool by changing the rod’s depth in the collect, and again the initial results were very similar, albeit with a slight bit more variation. I am encouraged, particularly because my current set up has the CNC attached to MDF that sits on a table, on the floor of an old house that flexes somewhat under foot, and the current prototype is mostly plastic, and attached to a separate loose but heavy board that sits on the MDF. I have attached a few photos for those interested.