Yesterday was the start of the series on assembling the BlueChick v4.2 CNC machine. We gave some suggestions on the general assembly process and showed how to assemble the deck for the machine. Today, we’ll talk a bit about our experience with putting together and installing the X and Y axis.
V-groove bearings are specialized bearings found in many linear motion systems. They generally ride on a rail or track. The BlueChick design pair the V-groove bearings with hardened aluminum rails for moving the gantry along the X-axis (the main deck). The sequence in the image above is typical of that used for mounting the bearing onto the frame. The item to note is the thin copper-colored washer. There should always be one between the V-groove bearing and the big black washer. This is so the bearing will not rub against the larger washer when rotating. The same sequence is true for the idler sprocket as well.
Note that the sides of the gantry are slightly different from each other. One has a cutout for the stepper motor. It is likely that the two sides could be swapped, but we oriented the piece in the same fashion as the video. The bearings are located in such that when tightened, they clamped the sides of the gantry onto the X-axis rails. Before attaching the side to the aluminum rails, we loosened the screws on the tracks so they could shift if needed. Fine-tuning the position of the bearings may be done by adjusting the steel bolts on the bottom roll of bearings. When properly adjusted the sides should slide along the rail of the bed freely.
Once both sides of the gantry have been installed and adjusted, the Y-axis rail may be mounted. The Y-axis rail, when attached, will stablize the the gantry structure. With the gantry constructed, it was time to lock down the rails along the deck. The best way to insure the rails are parallel is to push the rigid gantry up and down the deck while tightening the bolts holding the rails. When done, the gantry should be able to move without catching or snagging at any particular spot along the track.
The amount of work shown today took about an hour and a half. So the total assembly time to get us to this stage was a bit over two hours. However, one should take our time estimates only as a rough guide as we started and stopped quite frequently for photos. As stated in the previous article, there are lots of videos showing the complete build process. They are excellent, and should be the primary source of instructions on how to put the machine together. This series of articles is designed to supplement the BlueChick videos. We will have photos and suggestions to make the assembly process easier. We hope you will find it helpful. Tomorrow we will show the assembly of the Z-axis. It is probably the most complicated piece of the machine, but don’t worry. It was entirely manageable.