[George16]

That's not surprising. Just look at the amount of missing metal due to the hole bored to the shaft. Ever wonder why buggy/truggy pinion shafts don't have a hole on them?

Matt, you sheared them for the same reason I stated above. The output shafts have holes bored into them for the setscrews which reduced the amount of metal needed for strength and durability. The shafts are hollow due to the hole instead of being solid like the buggy/truggy pinion shafts.