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CNC tool setter

I had some keyboard switches left over from a previous project, and wanted a more convenient process for changing bits during a job.

Bit setter mountet to wasteboard
Bit setter mountet to wasteboard

This is a simple switch, wired in parallel with my touch plate, that is used before and after changing router bits.

When changing a bit, a macro offsets the Z height by the difference between the first and second tool length, and work can continue with the new bit.

This process is much faster than manual zeroing after changing bits, or using the touch plate. The tool can overshoot the switch’s trigger position slightly without damage, so the probe speed can be much faster than a touch plate, and it doesn’t require connecting the probe clip.

Additionally, if the original zero position has been carved away by the previous job, the tool setter can still be used.

It’s promising, but has some issues.

First, it has moving parts exposed to cnc dust and chips. I added a magnetic cover for it to help with that

Second, though it’s much lower profile than commercial options, it’s just about flush with the surface of my wasteboard. For surfacing, when I’m cutting off the edge, I’ve been pulling the cap off and taping it down. I’m planning to move it out in front of the wasteboard instead.

Third, repeatability isn’t amazing (around 0.02-0.04mm) because the 3d-printed button top I’m using isn’t a perfect fit on the switch, and the switch has some play as well. I’m looking to replace it with something with less play, but haven’t found the right thing yet.

3D printable files for it can be found here