How deep can a skid steer auger actually go? The short answer: it depends on your stem length, whether you're using extensions, your machine's lift height, the ground you're drilling in, and how rigid your setup is. Standard configurations get you about 0.9 m to 1.2 m without extensions—plenty for most fence posts and light footings. Need deeper holes for foundation piers, utility runs, or footings that go well below the frost line? That's where extension shafts come in. Here's what you need to know about how they work, what limits your depth, and how to get the most out of your setup.
Standard Auger Stem Lengths and Baseline Depth
Your baseline drilling depth comes from the auger stem—the shaft that connects the drive to the bit and carries the helical flights. TGEC's skid steer auger attachment comes with stem lengths of 915 mm (36 in) and 1160 mm (45.7 in). The 915 mm stem tops out at about 0.9 m to 1.0 m of usable depth, depending on how far the bit can sink before the drive hits the ground. The 1160 mm stem pushes that to roughly 1.1 m to 1.2 m. That range covers standard fence posts, sign posts, and shallow footings in most parts of the country.
One thing to keep in mind: usable depth is always a bit less than the stem length. The drive unit sits above the hole, and the bit's pilot point extends below the flights, so you're really looking at about 80 to 90 percent of the stem length in practical terms. A 1160 mm stem, for example, usually gives you about 1.0 m to 1.05 m of actual hole depth. If your job calls for more than that, you'll need to add extensions.
How Auger Extensions Work
An auger extension is basically a straight shaft that goes between the drive's output stem and the bit, adding length to the drill string. Extensions come in standard lengths—typically 600 mm (24 in), 900 mm (36 in), and 1200 mm (48 in)—though custom sizes can be made for specific jobs. They connect to the drive stem and the bit through matching hex or round interfaces, secured with pins or bolts that you can take apart in the field without a lot of fuss. Some extensions come with partial or full flights to help move cuttings out of deep holes; others are plain shafts that just add length.
Slap an extension on and you'll gain roughly its length in additional depth, minus a bit for the connection overlap. So a 900 mm extension on a 1160 mm stem takes you from about 1.1 m to roughly 2.0 m. Just make sure the extension matches your drive's stem diameter and connection type, and that it's rated for the torque your drive puts out. Run an undersized extension on a high-torque drive and you're asking for trouble—twisting or breaking under load is a real risk, especially in hard or rocky ground.
Stacking Multiple Extensions
Need to go even deeper? You can stack extensions end-to-end, adding each one's length to your total depth. A 1160 mm stem with two 900 mm extensions gives you a theoretical max of about 2.9 m. But stacking comes with real-world headaches. The longer your drill string, the more it flexes, and the greater your chances of bending, binding, or drifting off vertical. Every connection is another potential failure point, and each one adds a little bit of play that adds up over a long string.
When you're stacking, stick with extensions that match the original stem's diameter and connection type, and double-check that every pin and bolt is locked in before you start drilling. Torque demand goes up with depth—the longer string creates more friction against the hole walls, and cuttings have farther to travel to get out. If your auger drive isn't up to the task, you'll deal with frequent stalling and poor cuttings removal. As a rule of thumb, most skid steer auger setups handle two to three extensions before practical limits start to bite, though that varies with drive torque, bit size, and ground conditions.
Practical Depth Limits
So what's the real-world max? Most standard configurations can reach 2.0 m to 3.0 m with two or three extensions. Bigger, higher-torque drives with heavier stems and larger-diameter extensions might push 3.5 m to 4.0 m in good soil, but once you're past 3 m, things get progressively harder and slower. It's important to separate theoretical depth—the sum of all your lengths—from practical depth, which accounts for the real challenges of drilling, clearing cuttings, pulling the bit, and keeping the hole straight.
For most construction and landscaping jobs, the required depth is well within reach. Fence posts typically need 0.6 m to 1.2 m. Deck footings run 0.9 m to 1.5 m. Foundation piers often call for 1.5 m to 2.5 m, depending on frost depth and soil. Utility borings for water lines, conduit, and drainage usually fall between 0.6 m and 1.8 m. Only specialized work—deep foundation piers, well drilling, or geotechnical sampling—really needs more than 3 m, and those jobs are usually better suited to dedicated drilling rigs anyway.
Factors That Limit Drilling Depth
Skid Steer Lift Height
Lift height is often the first thing that stops you from going deeper. To pull the auger out of a deep hole, your loader arms have to lift the whole drill string—drive, extensions, and bit—high enough to clear the hole. If you don't have the height, you're stuck breaking down the string piece by piece, which is slow and awkward. Most full-size skid steers offer 2.5 m to 3.5 m of lift height to the hinge pin; mini skid steers may only give you 1.5 m to 2.0 m. Before you plan a deep hole, make sure your machine's lift height beats the total drill string length by at least 300 mm for safe extraction.
Bit Assembly Rigidity
Longer drill strings flex more, especially under torque. A flexing string drills crooked holes, rubs against the hole walls, and can bind or seize up. How rigid your setup is comes down to stem and extension diameter, wall thickness, material quality, and how many connections you've got. Bigger-diameter stems with thicker walls are stiffer—but they're also heavier and need more torque to spin. Dual-stem setups and extensions with larger shafts are worth considering for deep work. And don't skip regular inspections for bending, cracking, or worn connections—a damaged extension can fail catastrophically under load.
Soil Conditions and Torque
Soil type has a big say in how deep you can practically go. Loose sand cuts easily and lets cuttings flow up the flights, so you can drill deeper with less torque. Clay, on the other hand, sticks to the flights and builds up, increasing friction and slowing you down. Rocky or mixed ground can snag the bit, demand more torque, and cause the string to bind. As you go deeper, torque demand climbs—more flight length means more friction against the hole walls, and cuttings have farther to travel. If your hydraulic flow and pressure aren't up to the depth and ground conditions, you'll stall out and crawl along.
Operator Visibility and Control
Deep drilling with a skid steer auger tests your feel for the machine. Once the bit drops out of sight, you're relying on sound, vibration, and the machine's behavior to gauge progress. Push too hard and you'll bind or bend the string; don't push enough and you'll just spin. You also need to keep an eye on hydraulic temperature and pressure—deep drilling under heavy load generates serious heat. For holes past 2 m, having a spotter on the ground to guide you and watch the hole for verticality and cuttings flow makes a big difference.
Deep Hole Drilling Best Practices
If you're going deep, a few best practices will keep you safe and productive. First, consider drilling a smaller pilot hole before opening it up to final diameter—it cuts torque demand and helps with verticality. Second, drill in stages: run the standard stem, pull it out, add an extension, and keep going. That staged approach lets you clear cuttings and check the hole at each step. Third, use steady, moderate downforce—don't muscle it. Forcing the bit bends strings and stalls motors.
Fourth, pull the auger up partway every so often to clear cuttings off the flights, especially in sticky clay. That keeps friction down and flights clear. Fifth, check verticality as you go—use a level on the drill string or measure the hole opening in a few spots. Sixth, make sure every extension connection is pinned or bolted tight before drilling, and inspect them for wear after each job. Finally, match your auger bit size and drive torque to the depth and soil you're dealing with, and don't push your gear beyond its practical limits.
Final Recommendations
For holes up to 1.2 m, a standard stem with no extensions covers most needs. For 1.2 m to 2.0 m, one 600 mm to 900 mm extension usually does the trick. For 2.0 m to 3.0 m, you're looking at two extensions—make sure your skid steer has the lift height and your drive has the torque. If you need to go past 3.0 m, stop and think about whether a skid steer auger is really the right tool, or if a dedicated drilling rig would be safer and more efficient. Always use extensions that match your drive's connection type and torque rating, follow best practices for deep drilling, and you'll get straight, clean holes without breaking gear.
