Step 17: Y-Axis Motor Mount
This tutorial is dated, if you are considering a CNC for your personal use, we would highly recommend purchasing a kit that is very stable from our wide range of machines available
. Instead of using allthread for the lead screw and a standard nut, consider using a 5 start lead screw and anti-backlash nut
. It will keep you from pulling out your hair by running much smoother and faster.
We are down to the wire! For the structure of the machine, we only have the three motor mounts remaining. We have recently completed the last two screw assemblies (x and y). The machine now is stiff as an MDF board and won't move anymore. It was more fun without the screws, wasn't it. Now we need to add a method of spinning power to these screws. We can't just use our fingers to turn the screws, but we could attach steering wheels if you're looking for a manual routing machine. We won't be able to call it a CNC anymore, however.
Ok, back to the main subject, motor mounts. these mounts are real stupid simple. All we're going to do is take a piece of MDF and put about 7 holes in it, varying sizes of course. Four holes will attach to the motor mounting holes (it's the four holes that kinda stick out on the four corners, that is if you use a NEMA size). Some motors actually don't have mounting provisions. I can't help you there, but if it does, read and watch on. Are you still wondering what NEMA is? Ok, I won't leave you in the dark, it's a size and power specification. The larger the number, the larger the motor, and sometimes higher torque and speed. Some NEMA sizes overlap in power and speed, like a high powered NEMA 23 can match a low power NEMA. It stands for National Electric Manufacturers Association. Their charge is to make things compatible and provide standards. You can find out more at NEMA.org.
That's not all there is to the power and speed thing. Speed and power are also related to the electronics and software. That's another step but it's worth mentioning here. Before you make your mount, you will obviously need the motor. Select the motor that will be appropriate for your application. I talked a little about screws earlier on, but even the screws relate to speed and power. So, in all, what considerations do you need to ponder: size, power and speed of motor, the electronics and power supply to drive the motor to its fullest safe potential, the software and operating system, and the type of screw.
Ok, the other three holes on the mount will be for the shaft (in the center of the mount), and two holes to mount it to the gantry. For the motor mount holes, I use long #10 screws so the motor can be displaced from the screw assembly giving it room to attach to the coupler.