What's the Right Auger Bit Size for T-Posts?

30 August 2025 3 answers
Asked by GardenGnome123
I'm planning to install some 9-foot T-posts about 2 feet deep for a 7-foot trellis using a 5-foot high cattle panel, which will be set 2 feet off the ground. To make the process easier, I want to use an auger bit with my hand drill to start the holes. My goal is to get the posts at least 1 foot deep to simplify using a post hole driver afterwards. I've seen recommendations online for a 6-inch bit, but that seems focused on posts set in concrete, which I don't need since this is just for a trellis. What size auger bit would be best for this situation?

Answers

DIYQueen47
You might want to consider using a 10-pound sledgehammer to drive the posts in, too. It's another option if you're looking to avoid any drilling and keep it straightforward!
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RuralRover77
Definitely look into using a post driver instead of drilling the whole way down. If you're using a hand drill, you might want to check out T-Post drivers compatible with SDS hammer drills. It'll save you a lot of effort and keep the post sturdy without needing any concrete.
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HandymanJedi91
It's good to see you're thinking about the details for installing those T-posts! First off, you usually don’t drill for T-posts; you hammer them in. But if you want to make a starting hole, I wouldn't go deeper than a few inches—keeping them in compacted soil is key. A 3-inch auger bit should work well to create a solid hole for the bottom of the post, then you can drive the rest in with a post driver.
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