[seg9585]

$40k to print ABS? They probably purchased an Objet or similar that best uses FDM or Polyjet to much higher res and precision. You can probably get much cleaner tolerances with that printer compared to a Makerbot, Reprap, Cube, desktop printer but obviously at high cost.

Anyway we tried to print hubs last year but the motors tore them apart very quickly. Larger gears may work just fine as long as the gears dont have to absorb large loads (for example in a drive train, holding up robot weight on a large arm, etc). 3D printed gears would work just find for conveyors and the like, but pulleys would work even better.

The other issue is ABS and especially PLA tend to melt and warp if you attempted to drill a hole in them post-printing, so make sure the shaft size is correct the first time. Quick hint: on my Rep2 I increase the desired shaft bore diameter by 0.05in because the plastic tends to expand. Drilling out a larger bore will melt the plastic.

I recommend you test some of the print parameters and see what lasts the longest. For example, try adding additional shells and infill ratios, consider reducing your Z layer height, and even try printing in different orientations (vertical vs horizontal, etc).