PHD and tree roots

[ametcalf]

I have an older PHD that is a real horse. I don't know what brand but it looks like the blades that dig out the dirt, not the screw auger in the middle but the blades that run out from the middle to the edge of the hole can be changed. There is no need to change them now but it got me to thinking, can they be sharpened? I am digging some holes for a friend and we are hitting some 2" to 3" tree roots in some of the holes. We have been cutting them with a sawzall and using hand tools to get them out. I wondered if I sharpened those edges if they might slice, chop, or wear the roots away.
Any feedback on a better way to deal with the roots would be appreciated. The fence is in the middle of town so dynamite is pretty much out of the question unless we wait until the next 4th of July and try to pass it off for fireworks.
Thanks, A.Metcalf

 

[MMagis]

I think that the outer edges of the auger would contact the roots more than the tips. More than likely, the tips slide right past the roots while digging down, then the auger gets hung up. I guess I don稚 know for sure, but I don稚 think sharpening anything will help.
Edit: Thinking about it some more, maybe the tips would contact the roots, but I think anything you sharpen would dull extremely quickly. The add on cutting tips may be worth exploring.

 

[bcp]

Maybe small cutting tips added to the auger would do it, kind of like this one: