I bought a low hour (<500) Bobcat 773 and the previous owner has offered to sell the Bobcat 12 auger (that's the model #) with 12" bit (unrelated to the model #) for $600. The bit has replaceable cutting edges.

I have a new SpeeCo 12" auger on my Kubota tractor, but I am thinking the price is good and this would allow me to run larger dimension augers (I'd like to run an 18 and maybe a bigger one for tree planting) without killing my old tractor.

Was the 12 a good model? Will it effectively run larger bits (18-24") and do so on my 773 without high flow?

The gearbox is a bit rusty but it's been shedded and I believe it to be in good shape overall with little use.