The auger does the digging. Your job is not to fight it.

Quick answer: Call 811 before you dig. Dig when the soil is damp, not dry and not soaked. Let the auger's weight do the work, lift to clear the hole every few inches, and plan on burying at least a third of the post. The hole only has to be roughly straight. It's the post that has to be plumb.

Call before you touch the ground

In the U.S., dialing 811 gets utility lines marked for free, and the call takes about five minutes. Do it a few days ahead, because the crews need time. A fence post through a gas line ruins more than your weekend.

The marks don't cover your own pipes. If you've got a septic system or a private water line, you're the only one who knows where they run. Find the tank and the drain field before you plan the fence. The rundown in What a Well and a Septic Really Cost to Keep Running is a good place to learn what's under your yard.

Then walk the line. Run a string between your end posts and spray-paint a dot at every post location. If your spacing is eight feet, measure it with a tape and not with your boot.

Pick the machine for the dirt you've got

A one-man gas auger is fine for soft loam and a short run of fence. It's miserable in clay, in rocky ground, or for a hundred holes.

A two-man auger takes two people and cuts faster, but it can throw both of you if the bit catches. A tractor or skid-steer auger is the best answer for a long fence. Rent one for a day if you don't own one. It costs less than a week of sore shoulders.

A manual clamshell digger and a five-foot steel digging bar still earn their spot in the truck. You'll want them near rocks, near roots, and anywhere the machine can't get to.

Start the hole right

Straight starts at the surface. Use a flat spade to cut the sod, then dig a shallow dimple about as deep as the spade blade. The bit's tip needs somewhere to sit. Otherwise it walks across the grass and you start the hole a foot from your paint dot.

Set the bit tip in the dimple and hold the auger upright before you pull the trigger. Check it from two directions, ninety degrees apart. Your eye lies from one side. If a buddy's around, have him stand off to the side and tell you when you're leaning.

Start at low throttle. Once the flights have bitten, open it up.

Don't lean on it

This is where backs get hurt. A sharp bit pulls itself down. If you're pushing on the handles, the bit is dull, the soil is wrong, or you're about to bend the shaft.

Stand with your knees soft and the handles about hip height. Keep a loose grip and don't wrap your thumbs around the bars. Let the weight of the machine settle and guide it. Pushing down just wears you out and drives the bit sideways.

Every six inches or so, lift the auger partway out and let the dirt spin off the flights. Skip this and the hole packs with loose soil, the bit binds, and you're fighting it for the last foot. Dump the spoil on a tarp. It keeps the lawn clean, and you'll want that dirt close at hand for backfill.

When the auger grabs

Sooner or later you hit a rock or a root. The bit stops, but the engine doesn't, and the handles want to spin you around.

Know where the kill switch is before you start. Let go the instant the bit locks up. Don't try to muscle through it. Clear the hole, shut the engine off, and use the digging bar to find the obstruction. A rock under a foot across can often be pried loose and lifted out. A big root gets chopped with a mattock or a sharp spade.

If the bit hits something it can't beat, move the post a few inches rather than wreck a shear pin or bend the auger. Hold the line with a string and the fence will still look fine. Wear steel-toe boots, snug sleeves and eye protection. Nothing loose that a spinning shaft can grab.

Clay is its own problem. If it's dry and hard as brick, pour a few gallons of water into the hole and wait twenty minutes. Soaked ground is just as bad, since it smears and sticks to the flights. Damp is the sweet spot.

How deep is deep enough

A common rule is to bury about a third of the post's length. For a six-foot fence that's two feet. For an eight-foot post, closer to three. In places where the ground freezes, the bottom of the hole needs to sit below the frost line, or the post will heave. Your county extension office knows your local number. What Freezes First on a Property and How to Stop It covers why that matters.

Corner, gate and brace posts carry the load of the whole fence, so they go deeper and wider. The Corner Posts Decide Whether Your Fence Lasts Twenty Years covers that in detail. Skimp on them and the rest of your work leans over in a couple of winters.

Make the hole about three times as wide as the post. A 4x4 wants a ten-to-twelve-inch hole. That leaves room to tamp or pour around it.

Set it plumb

Dump a few inches of gravel in the bottom so water drains away from the end grain. Drop the post in. Hold a four-foot level against one face, then an adjacent face. Brace it with two stakes and a couple of scrap boards.

Backfill in layers. Shovel in six inches, then tamp it hard with a steel bar or the end of a 2x4. Repeat to the top. Tamped soil is stronger than most people expect. If you pour concrete, mound it so water runs away from the post instead of pooling against it.

Check plumb again before it sets. Fix it now, because you can't fix it later.

Give it back clean

If you rented the auger, wash the clay off the flights before you return it. Fill the gas tank, even if it came to you near empty. The guy behind the counter will notice, and so will the next customer.

And if the line runs along a neighbor's property, tell him before the digging starts. A two-minute conversation over the fence is worth more than a survey stake. The Unwritten Rules of Having Neighbors in the Country covers the rest.

Then stand back and sight down the fence line. If the posts look like soldiers, you did it right.