Driving in the 3 1/2" steel rockspike. You can drive this rockspike in the ground about 42". This ground is very rocky. You can see the old ties are barely in the ground. Behind me you can see the first 3" steel pipe I put in, it is 8' long. (3 1/2" O.D.) This post pounder has worked great, I have only had it a few weeks.
I have used this post driver a lot more and it is awesome. It is well worth the money if you have a lot of fence to build.