In version 0.92.6 we have added a cnc mode for this. To activate send M453. In config tool you can define your spindle connection for this case. It adds commands M3, M4 and M5 to control a spindle like other CNC software does. Also do nor forget to include arc support. Then you should be able to do some easy cnc things. The biggest problem left is getting start condition with object placement and tool length.
In online tool select in tools tab cnc mode and then you can define your spindle control pins and get the above commands.
