I broke some needles a long time ago on a NH baler. I went to the dealer who had new ones for a high price, and used ones for half that but still a couple of hundred. I had a very good welding shop fix the snapped needles for maybe $50 figuring if they broke i knew that the large dealership carried used ones. I sold the baler after several thousand bales on the welded cast iron needles, they were doing fine. I also got wind of a retired ag mechanic who charged me next to nothing to time my baler as obviously it was over my head.
You might want to check the part number on the ones you are replacing as it seems to me that other JD square balers might use the same needles. Maybe. Ask locals who might know someone in your area, and scour google and ebay
