For the past three days we have been discussing the assembly of the frame and axesof the BlueChick v4.2 CNC machine. Now that most of the structure has been assembled, we now shift our focus to the installation of the motors and the associated drive mechanisms.
The next order of business in the build was to install the holder for the router. The holder for the BlueChick was designed specifically for the Porter Cable 892 series router. That specific router was chosen because of its straight cylindrical housing, which enables the use of two rings for a rigid mounting. The rings are mounted on a plate which travels up and down. Ensuring that its travel is true and controlled is the job of the lead screw and the stepper motor.
The assembly of the mount and the installation of the motor were easy to follow in the video. We did have a little bit of trouble pushing the bearing for the lead screw into the support, but a pair of open-jaw pliers helped us work it into the piece. The other thing we had some problems with was getting the lead screw into the anti-backlash nut. It took us a little while to figure it out, but in order to get the screw into the nut, the spring on the nut must be compressed.
The Z-axis motor is next to the router mount, not on the top of the Z-axis assembly. This reduces the overall clearance required by machine. We may rig up a vacuum attachment for the router. We are not sure where is the best place to mount the hose, but not having the motor up top will give us more room to play with.
The Y-axis motor is for moving the router back and forth along the gantry. The movement is controlled by the stepper motor driving one roller chain. Installation of the Y-axis motor was straightforward, but space is tight. An open-ended wrench will make tightening the nuts easier. The one thing to note is that this is the best time to make sure the drive sprocket is screwed down tight on the steel spindle of the motor. Getting at those screws will be a lot more difficult once the motor is in place.
The remaining motor is for moving the gantry up and down the X-axis. This is the largest movement and is controlled by the two roller chains on the side of the deck. We’ll show the mounting of the X-axis motor and drive chain tomorrow. Total construction time so far…about five hours. Not bad at all.