A friend of mine bought a $1500 self contained
chipper with a 2" capacity. He brought it over to my house one day when we were milling some logs. While he was running the mill, I muscled it down and out of the back of his truck, got it started pretty easily, then took a 1" square pine sticker and put it down the chute. It had all it could do to chip that sticker. I figured I'd try a branch, a SMALL branch, maybe 1" in diameter but with a lot of twigs on it, I actually couldn't get the
chipper to chip it.
I then proceeded to muscle it back up into the back of his truck, and left it there, I never used it again, and I don't believe he has either, this was years ago.
I now have a Vermeer PTO
chipper, and I can put a 5" diameter small tree into the chute, hit the hydraulic feed and walk away, by the time I get the next limb loaded, that one is already turned to mulch. I would never consider a self contained gas
chipper like that again.
Like amigauser said, if it was a self contained diesel like Vermeer or others, then that's a different story.