I have had excellent results acquiring used and aftermarket parts for my NH 273 baler from:
1. All-States Ag Parts. They have a network of dealers. I've gotten parts from their dealers in Wisconsin, Minnesota, and Iowa, Google their name and you'll find a phone number. The one that I always start with is (877) 530-4430.
2. Fry's Machine in PA. Their number is (570) 546-3968.
I'd be shocked if one or both of them couldn't fix you up.
Tom in TN