Digging Post holes

[Threerots]

Hey guys,
I need to dig a hole for a 12 foot by 8-9 inch pole. I have a 9 inch and a 12 inch auger. The ground is concrete hard and possibly within the root radius of a large tree. My question is would it be easier to drill an initial hole with the smaller auger (like a pilot hole) and then enlarge it with the larger auger or just start out with the larger auger.
Thanks
K

 

[RjCorazza]

I would just start with the 12" auger.

 

[Rockbadchild]

Just start with the 12'' if that's what you need if you do a 9'' first then go the 12'' the bit won't stay center it will slip to one side.

 

[RjCorazza]

They also can rattle around, sometimes violently in a pre drilled hole.

 

[Rockbadchild]

I have done many holes in hard dry clay, I needed to climb on the post auger for it to dig, in the future I will weld a vertical shaft on the post auger in order to insert weights to it instead of my body weight. I know rocks are a pain when you hit them good thing I don't have very many. I imagine large roots could be a problem I am guessing you will have to cross that once you get there.

 

[grsthegreat]

I got a power down assist on my speeco post hole driller that helps alot. As i recall it adds 250# of down force.

PHD - Down Force Kit

I purchased a Down Force Kit for a PHD from My local JD dealer. No one seems to know the answer to my question related to the plumbing of the hydraulic on this down force kit. The hydraulic cylinder has two ports, you would assume that one end is to extend and the other is to contract but no...

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[MMC]

Hey guys,
I need to dig a hole for a 12 foot by 8-9 inch pole. I have a 9 inch and a 12 inch auger. The ground is concrete hard and possibly within the root radius of a large tree. My question is would it be easier to drill an initial hole with the smaller auger (like a pilot hole) and then enlarge it with the larger auger or just start out with the larger auger.
Thanks
K

I would use the 12." Don't know your soil, area, and schedule, but waiting for rain is always better. If you have to dig now, I would take your sharpened digger bar and chip off the top layer of sod and hardened soil, to help the auger "bite."

Second, sharpen your auger advance knives as much as possible, and often, when digging.

If this is a big tree, any larger root is going to stop you and shear bolts/pins. You will have to take a chainsaw or something else and manually clear the root ahead of the auger. So, if possible don't get into that fight. Identify your root "leaders" going out from the tree base and dig in between them.

If it's not solid clay, you can fill the hole with water overnight to soften the soil since you're only doing one hole.

Last, buy some extra shear bolts/pins and don't use anything harder than recommended by the manufacturer. Pull your digger up often to clear it to keep from "screwing" it into the hard ground and breaking yet another shear bolt...

I personally would not ever stand on the digger frame to add weight - could be your worst day ever...

Good Luck.

 

[grsthegreat]

I find that the best time to dig post holes is right after snow melts and ground thaws. Way way way easier than later in summer

 

[beeforty]

I find that the best time to dig post holes is right after snow melts and ground thaws. Way way way easier than later in summer

Definitely better digging with moist soil! But watch out if you have clay type soil and don't raise your auger frequently to clear the hole, you can screw your auger into the ground and not be able to raise it up! Been there and done that, plus there is no reverse for the auger unless you have a hydraulic unit! Then you have to disconnect the auger and manually unscrew it out of the ground. Not and easy task and may need a large pipe wrench for leverage. Same thing can happen with roots if the leading edge slips under a root in soft soil, it just pulls the auger into the ground like a screw into wood.

 

[goeduck]

I have a hydraulic auger on the FEL with down pressure and reverse, so can't comment on 3-point tactics. But, I'd go with as large as possible at first, your 12" or borrow a 15". The holes don't necessarily go straight in roots and rocks, so wider can help.