Metal posts are convenient anchors for fence trellises and other structures in the garden because they are light weight, durable, and secure if properly installed. They also can be easily uprooted and moved to another location.
If you have been driving metal posts with a sledge hammer or other such bludgeon or have been using a post driver--effective but heavy--Gardner Ed's Post Jet is a great alternative. I like the Post Jet because I move my fence trellis, posts, fence and all from one spot to another, and I can't use the post driver with the fencing attached, but a Post Jet would work just fine.
See instructions below for Ed's easy to assemble Post Jet.
This is a cheap and easy tool to set steel posts for garden trellises.
Schedule 40 PVC, 3/4 inch inside diameter, is sturdy enough, even in heavy soil because it has a 1/8" thick wall.
These are all slip fittings that have to be glued with 1) PVC pipe cleaner; the purple stuff. 2) the actual glue is really a solvent the "melts" the pieces together for a very strong and water proof bond. The garden hose adapter does what the name says; it adapts the tool for connection to a garden hose. Turn on the water and jet a post hole. It's easier than using a sledge hammer.