Step 18: Z-Axis Motor Mount
With the Y-Axis Motor in Place, we can now start on the z-axis. I know you're probably thinking, what are those motors and what are its specifications (torque, what that means, wiring, power, etc.)? That information will be made available during the electronics portion of this video series coming up after the x-axis motor mount. And yes, I'm going to bore you with yet another motor mount. The process wouldn't be complete without it.
For the y-axis motor mount, however, the process is almost exactly the same, with the exception of a few things on the y-axis top bearing support in the way. Remember the two screws that fasten the top of the z-axis rail support? They get in the way. You will see me countersink them at the end of the video after much of my frustration has been exhausted. But, that's not all. I started out in error as I placed the motor mount reversed on the top and then started drilling. it's a sight to be seen. I fixed it in the end, even when I though that I would have to remake the y-axis top bearing support. So, no matter what happens, there is usually a solution.
In this video, I demonstrate the wrong and the right way to mount the z-axis motor. I start out with a small piece of wood about the size of the motor front plate, but wider so two mounting screws can be affixed to the y-axis top bearing support. Drill the hole in the middle for the shaft and position the motor on the piece to mark for the mounting holes. Drive nuts into the holes for holding strength and place the piece on the z-axis and drill two more holes to hold it in place. Sounds simple, right? Well... you'll see. The moral of this story, watch the complete video before getting started, just like the teachers said in school.
The y-axis top bearing get's used like a cheap... huhmm... Like I said before, almost every piece of the CNC machine has two functions. In the case of the y-axis top bearing support, it has three functions, to hold the bearing for the y-axis, to help support the z-axis rail and finally to mount the z-axis motor. It's best to design with efficiency and simplicity in mind, and cut out all of the superfluous material. Extra material should only be used if the material's propertied are not adequate for the job, then structure is needed to essentially engineer the inadequate material. To elaborate, If I wanted to use 1/2" MDF, I would probably have to build a frame for each axis to reduce the tendency to sag or bend.