27 x 64 Belt Drive Machine

These plans are no longer available. The rack and pinion machine replaces the belt drive.

Belt drive table

Since this machine's development, more CNC components have become available for the DIY market. The part limitations that this table was built to address no longer exist.

Attributes include:

  • Fast
  • Large
  • Accurate for cost
  • Designed around Xylotex and HobbyCNC kits
  • Uses a trim router to its potential
  • Framing lumber X axis construction
  • Standard sized aluminum Y and Z axis construction
Belt drive systems are around 95% efficient. Therefore, the steppers and drives from Xylotex and HobbyCNC can rapid the axes over 300 inches per minute.
The build price of the newer Rack/Leadscrew machine is comparable to the cost of this belt drive machine, and the Rack/Leadscrew machine can carry a full sized router.

Belts are very efficient, but they do not permit aggressive router work because they rebound.
The machine is made of lumber and 1/8 and 1/4 inch aluminum stock. This metal does not require special tools to work. Hacksaws or carbide blades will cut it, but the metal is not as rigid as steel or thicker aluminum.

Because of this strength limitation, this machine is designed to use a trim router.
The machine will flex or chatter before a full sized router is pushed to its potential.

The stepper system was the 269 oz.in from Xylotex. The HobbyCNC 305 oz.in. system performs similarly to the Xylotex 269 oz.in. system.

The HobbyCNC 200 oz.in. system was also tested. With slightly different gearing on the X axis, it was able to rapid at 200 rather than 300 ipm while supplying adequate cutting forces.

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Belts are forgiving of misalignment; however, they can rebound under high accelerations, which can cause the router bit to leave a wiggly trail as it bounces back into line.
This is resolved by slowing the stepper's acceleration in the software. The feed-rate can remain high, so the stock can still be cut quickly.

The longer the belt, the more rebound there will be. Long belts are costly, and all belts wear with use. The heavier the use, the sooner the belts will need to be replaced.
Rack and pinion, and leadscrew drive machines are not as efficient as belt drive machines, but the components usually last longer and they are capable of carrying heavier loads with less rebound.