I’m learning a lot about CNC operations, CAD/CAM, etc with my new lowrider. I got a wild hair and decided I have to have some cam clamps for use on my spoil board. I chose to use the solution by Adventures in Creation which is a twist on Marius Hornberger’s cam clamps. 3/4" EMT conduit is the ‘dowel’ in this system.
I use Linux with FreeCAD to CAM things up and CAM them to gcode, and the same PC runs CNC.js for running the gcode. I ran a lot of test holes and settled on a pocket and helical drilling operation for accuracy and speed to create a hole that is a snug fit for the conduit.
FreeCAD doesn’t have a concept like EstlCAM of a finishing pass, so I ran two operations. The pocket I ran at higher speed and held it off the diameter by 0.1mm, then ran the helical slower. But the helical wanted to do the entire hole over again, so I cut out all the gcode except for the final helical around the diameter, this is the finish path. There may be other ways, but I’m feeling my way along and learning by trying things.
I then took that gcode and manually edited it to create a single row in the X direction across my spoil board; 11 holes at 750mm spacing, using G91 to switch to relative coordinates after each hole, move right 750mm, then back to absolute with G90 and reset X with G92. Then drill another hole and repeat. At the end of the row, move relative X-750 Y75 and end. Then I can run it again for the next row. Each row takes about 14 minutes.
CNC.js is helpful in that it shows what the gcode will do. My old 'merican brain is calibrated in inches so I make mistakes with mm and it showed me a hack that had me moving 10x too far back to the left side of the board.
Anyway, this is just plain fun.