Newbie Safety Question

Hey there. I’ve been progressing quite well (at least I think so) getting some basic projects off my machine. I have a Gemitsu 4040PRO and I’m running gSender to control it. My next project will require me to change bits/toolpaths to finish it and I’m looking for input as to the safest way to change bits and not lose positional data. Can I simply power off the engraver, complete the bit change, re-power and continue? Or is there a specific sequence of things required?? It does have hard limits so I could re-home it each time as well. And I’m aware I have to retouch the tool height with each change. I’m not too concerned about axis movement, but don’t want any unexpected spindle starts. I was think of adding an auxiliary switch on the spindle leads, but since the machine didn’t come with one I’m thinking there must be a standard way of doing this.
Any input is greatly appreciated !!! Cheers.

Hi @Turdmagnet, I’m not familiar with the Gemitsu - does the spindle have a separate power supply (or an emergency stop)? My procedure with my longmill is to turn off the router (as it is just a router) and swap bits, so that I don’t lose my X and Y. Then a quick touch off with the Z to set the zero and I’m good to go.

Another way you could do it is to drive the mill to a known x, y (doesn’t even have to be 0, 0) and power the whole thing down. Just make sure to not home GSender after powering the mill back up - just input the known coordinates.

The final way would be to build some feature into your work piece to set x, y, and z zeros on. As long as you don’t dismount the part, you will get a very accurate zero.

Hope that helps!


I run my LongMill just like elbarsal, and have no problems.

I turn the router off to change bits then zero and hit go. So far I haven’t had any issues with my Longmill.

It should work for your machine too.

1 Like