I borrowed a friend's old Black and Decker chipper and it was quite good, though much bigger than 1" is starting to get a bit tough, but then Robinia burns very well (like Ash it burns green) so I'd keep anything bigger than that for fire wood. However, even the tiniest bits of grit badly blunted the blades, and bigger bits of grit knocked chunks off the edge and made sharpening a real chore, and unless the blades were really sharp it didn't work at all well. I made myself a sharpening jig and that helped a lot, but doing it freehand is totally out of the question.
The model is obsolete now so that probably doesn't help very much.