Post hole digger augers

[Carver_Bill]

Comments, suggestions welcome!

Getting ready to use my MF900 post hole digger to install a new fence with about 40 posts (4x4x10' cedar). I got the MF900 with a 6" auger when I bought my GC2310 at the end of 2005.

I've read a number of posts that recommend a 9" auger for 4x4 post although at least one post recommend 6" to minimize lose soil..... Hopefully I can deal with the 6" auger - fingers crossed. BTW the wood will be delivered next week.

A bigger issue is the depth of the post hole. I planned to dig 48" hole, 4" gravel and the posts app. 44" in ground, 6' 4" above ground (10 ft. posts). Also plan to backfill with gravel. The auger is ONLY 42" long and I doubt I be able to get it to dig that deep??? Anyone know if "auger extensions" are available for MF900s/augers? I've seen extensions on the Northern Tools website but the parts fit a specific brand "power-head".

My dealer and they were not aware of any extensions for the auger. Also, if the 6" auger doesn't work, the dealer will sell me a 9" standard auger for $116 or heavy duty for $186.

I guess worst case is digging with the auger to max depth and then finishing the "old fashion way", by hand (argh!!).

 

[BTDT]

Good evening Bill, and welcome to TBN. If you have a longer auger, will your tractor raise it high enough to clear the hole. And just a suggestion, the auger may be long enough, but you may be able to weld up an extension on the top (pipe at top of auger that hooks to phd gearbox) for more reach/deeper hole. This may depend on what type soil your operating/digging in also. Good luck.

 

[Mike120]

Just use a manual post hole digger (idiot-stick) to extend the hole. You'll probably need it anyway to get alignment of the posts. The reasoning behind the bigger augers is to have some wiggle room to get the posts to lineup straight 'cause the holes seldom do.

 

[knute_m]

Comments, suggestions welcome!

Getting ready to use my MF900 post hole digger to install a new fence . . .

A bigger issue is the depth of the post hole. I planned to dig 48" hole, 4" gravel and the posts app. 44" in ground, 6' 4" above ground (10 ft. posts). Also plan to backfill with gravel. The auger is ONLY 42" long and I doubt I be able to get it to dig that deep??? Anyone know if "auger extensions" are available for MF900s/augers? I've seen extensions on the Northern Tools website but the parts fit a specific brand "power-head".

I guess worst case is digging with the auger to max depth and then finishing the "old fashion way", by hand (argh!!).

I think you may be over doing it with a 4-foot deep hole. I've put in a lot of fence posts in the last half century, and 1/3 below ground is more than adequate in most soils.

And their ain't no way you will dig a small diameter 4-foot deep hole with a manual post hole digger. You can't spread the handles far enough out to remove the dirt from the bottom of the 4-foot hole.

I "Googled" an MF900, and it appears to use standard 43-inch augers. I don't know of anybody who uses longer augers for fence posts, or even small pole barns.

But, I would seriously think about a larger diameter auger.

As was mentioned, a 6-inch auger doesn't give you much wiggle room. I use a 12-inch auger for everything from sinking small posts to planting bushes and tomatoes. Twelve inch may sound big, but it doesn't take much to fill the holes back in and get them properly tamped.

Good Luck,
Knute