Once I got the frame together this is what it looked like. The red bearings were problematic as the outside diameter is 7/8" and I could not find anything that fit them. That is about 22 mm diameter. There are some 22 mm clamps that are used on Drones but they are wimpy as they were not designed for use on a CNC machine.
|T Slot CNC Frame|
The new Z axis is only four inches wide. This next picture shows the new Z axis in front of the old six inch wide Z axis.
|New Z Axis|
1. A 10-32 screw fits the T slot nuts.
2. A 10-32 Truss head screw head fits the T slots.
3. A standard 10-32 nut, once filed slightly, fits the T slots.
Here is my current state of construction, the fully supported rails and matching bearings is a huge improvement well worth the $40.
|T Slot CNC being assembled|
|Close up of Z axis|
Then to load GRBL select grblUpload and open it.
Next set your steps per mm as in $100=320, $101=320.
Then check to see if a 10 mm move in X and Y move exactly 10 mm.
Then check to see if a 100 mm move is in fact 100 mm.
Next attach a marker and print something.
I found a file that prints a 5 inch ruler that is a nice test of the CNC.
Here are the drawings for the smaller Z axis. Sorry the drawings are from Visio not Autocad.
Z Top (and Z bottom with no holes for stepper motor):
Note that 10-32 screws will fit the 12 mm bearing blocks.