Heres a post hole auger I built, The tube is 2 7/8 pipe. I bought the gear box on e bay for 100 with shipping and also the auger for about a 100 with shipping. I had the driveline already I got about another 50 in odds and ends as well as gas and rods. 250 total. It works pretty good...
I used to pull this plow with a Fordson major. Was glad that the NH TC40DA SS pulled it as well as it did, had to keep in 4WD. I think the Fordson would have pulled it in two. But the NH will turn some dirt. I also have a IH 474 that handles it pretty well.