the hammer keeps mining in a ring underneath the block i mine and it makes the hammer completely useless.

My vanilla+ excavator also digs out a 3x3 ring leaving the middle block remaining instead of digging all 3x3 (9 blocks) out.

That means there is lag. You have to keep targeting the main block.

There is no lag on server (it instantly reports lag on the server console when it is occuring) and I had 115 fps at all times when I was using this. There were only 2 people on the server with all Sam's mods on it and it has been running at 20 20 20 tps. NOTE that this center block DOES get removed if I stand ON the layer of ground to be removed and then look down at my feet. But, if I point at the layer to be removed from one block lower then it does not work properly. And, this was consistent and repeatable.

This is a good server report IMHO