It does not dig very deep but I suspect most of us do not need to go deeper that a foot or so very often. Most places the ground does not freeze deep enough to require burying irrigation pipe deeper than that.
If I had one the first thing I would do is to use it for planting an asparagus patch. Might also be useful for planting berries, potatoes, etc. Faster than digging separate holes and a trench would allow one to lay in a buried drip irrigation tube than ran the length of the row.
But in the heavy red clay of NC the PT-425 doesn't have enough power to use anything bigger than the Power Trac Potato Digger!! /forums/images/graemlins/frown.gif
Power-trac 422 2003 model and 428 January 2015 model
Yes 14. I think that the potato plow would put more power in its bite because the digging point is closer to the PT. I would recomend to anyone building one that they stick close to the PT design. I built mine like I did because my dad wanted it that way. It was mostly for him. (But it does work well)