Small Herringbone Drive Gear Hard to Install

I re-printed a couple of the small herringbone extruder drive gears as the one that shipped with the printer broke and I wanted a couple of spares just in case. When I tried to put the new one on that I printed, it took a huge amount of effort to try and push it onto the stepper motor, to the point I thought I might break the motor. Also, trying to get the small nut into the hole in the bottom of the gear was really difficult as well. These were printed in ABS.

Are the variances supposed to be this tight for these parts, or is there something wrong with the prints?

The parts are tight. We will drill out the center shaft for the stepper motor shaft. The captive nut is pushed in.