Posthole Digger Need Auger with 2-bolt connection

[LouieJunior]

My PHD gearbox output shaft is 2-inch diameter with 2 holes through the shaft. My 12" auger bit fits over the output shaft and has holes that line-up with the holes in the gearbox shaft. I'd like to locate a smaller diameter auger bit but I don't see any that will connect to my PHD.
Does anyone have any guidance on where these might be ordered?

 

[alextassos1]

Tractor supply or rural king.