I keep one 'hanging around' literally, in a tree, for when I need it. Bought it used years ago and have used it quite a few times.yes but as said, some 'limits' apply...
biggest factors are 1) frost line, 2) soil conditions 3) real use qty ?
1) most augers go 36"...frost line up here is 44" ! hmmmm
2) sand..NO problem....terminal moraine.. forget it !!!
3) it's one tool I decided I don't NEED, even though I've set 100s of posts in 3 decades. To make money, you need to drill FAST,deep and accurate.
consider , if it's a one shot deal..rent a proper unit...cheaper
if it's for commercial use...rent a proper unit ...cheaper
friend put in over 100 in one day, used his TLB to PUSH the posts in.
We used a Landpride 6" auger with our BX2370 and it worked very well. We planted 100's of tree saplings. We are in sand so that might make it an easier job than other soils, but we cut through tree roots with some frequency and it didn't slow it down.
Torque is the PROBLEM with those things. TWo men dont have enough weight and grip to hang onto it when it hits hard digging.check what homedepot rents for post hole diggers ! 9.5HP 2 man unit will do 18" holes !!
you don't need a lot of HP, torque is more important, and KNOWING what the soil conditions are is the MOST important thing !!!