As you all know the CNC project has turned into a Heath Robinson cartoon. It’s mostly due to trying to build this unit at little to no cost from junk I have came across. Here is a short list of ways to find parts for building a small table top unit.
A CNC can be made out of wood, metal and even plastic. So far mine is made from all three. All what matters is can it move X Y and Z.
Old computer hard drives are great for bearings. The heads have a small bearing that is secured with a snap ring and can be easily removed. Even a hard drive spindle motor is fine to be used as a bearing for the gantry since it has mounting points on them. You could probably get away using a total of four motors for the gantry to move on the X axis.
Stepper motors come in all types and sizes and mostly run on 12 or 24 volts DC. You can get these out of old printers, photocopiers and if you are lucky old computer 5.25 inch floppy drives. Most of the time these used motors are six wire unipolar and hard to find documentation but you can sniff out the correct pins with a multimeter. Some motors are backwards compatible and can be used as bipolar. It really doesn’t matter since you can just toss 12 or 24 volts onto the common lead of the motor.
Limit switches are nice and not really needed but some people like them. They’re just a MON-SPST switch.
The driver board is simple. Just Darlingtion transistor arrays and diodes if yo plan to use a parallel port.
Motor belts can be salvaged from printers, fax machines, photocopiers and such. Same with rods for the bearings to ride on. At times a printer will have two rods but different diameters. You can also salvage pulleys as well for the belts however they are plastic and could strain with a heavy Z axis.
You can use anything to power the unit. If yo use a stepper motor that uses half steps it will draw more amps but if you use full steps it uses less. In all a old PC power supply is more then enough. You might even be able to use a power supply from a old laptop or even a printer.
The spindle can be a hand router, dremel or a high torque motor depending on what you want to cut with it.
You can use stuff that didn’t come from electronics. I was able to score a bunch of 3/8 inch tubing from two old youth beds that can be used a glide rails. Recyclable plastics such as HDPE (No.2) used for milk jugs and plastic coffee cans be be easily melted to make one off parts. I myself plan to use to make the spindle holder.
As long as you have the right tools and understanding on things you can use all kinds of stuff for projects.