I've been running these NI disc cutterbars for 25 years. Cut at 10 mph without ever slowing down... run all day long, day after day after day that way. Don't think I've ever had it plugged. When I was in the hay business, I used to cut in heavy downpouring rain even... remember pushing water 2-3" deep ahead of my tractor tires at times. They just work.
The turtles turn in alternating opposite directions (CW/CCW), so if you rotate one turtle a little, you can make them all look like pic #1, turn a quarter turn, and it'll look like pic #3. That's for all except the first one on the drive input end on the discbines (not sure right now about on the 3 pt. models).. that outside turtle turns in the same direction as the second one on the cutterbar... so it has to be timed just a little off from the next one, so the knives won't strike. It's supposed to be like about one gear cog [behind?], if I remember right. It explains it in the owner's manual.
They are a great mower... IMO the best disc mower cutterbar design available (in either the discbine or 3 pt. disc mower version). The red ones have a SEGMENTED hex shaft drive in the cutterbar from the factory... much better than the grey ones which had a single shaft running through the bar from one end to the other. The grey ones were a pain to take apart, because that shaft can/will get twisted in use eventually, and then it becomes almost impossible to slip the turtles off of it. Most of the time you'd end up cutting the shaft, and then replacing it. No reason why it can't be "segmented" though in the center of each of the gearboxes, which is what NI did on the red/newer models. That shaft might be a little heavier in the red ones too... not sure. I had a red 3 pt. model first, then a grey discbine, and two more red discbines over the years, and I picked up 3 more 3 pt. units again too, for ditch mowing, etc. Grey ones also have a smaller hole in the blades than the red ones do... wears out the pivot bushing quicker. The red ones are better.
I also have a CIH unit that looks almost identical... but it's NOT THE SAME. That cutterbar shaft in them is square, and runs the full length... but worse, it's a way LIGHTER shaft... only a 1/2", and square instead of hex (how did some engineer ever think that a 1/2" shaft would be heavy enough for that????)... it looks just like it could be regular old key stock material, except that it has to be a specially hardened shaft... VERY expensive, and almost impossible to get your hands on one anymore. I think for my short 6' mower it was gonna be something like $1700 just for that shaft... IF you can get one. It had worn the corners off (part of why it has to be specially hardened), so I ended up welding it back up and grinding it to fit because I couldn't get a new one at the time. Then it broke right by the first drive turtle... I was able to put it back together and then turned the shaft end for end so the only thing that weaker spot was having to drive was the LAST turtle... so far it's holding together, but I've been taking it really easy on it since then. I should sell it on an auction... and be rid of it. Point is, stay away from the CIH models like these, and find a NI/Hesston/MF unit. Those are all the same and most parts are interchangeable, if they have those same turtles on them.
Wish Agco/NI/Hesston/Massey hadn't bought out a European hay equipment company and then switched to the "rack of gears" cutterbars that they're selling now. Nowhere near as good a machine. Vermeer now sells that cutterbar system that NI used to have, with a few modifications of their own... and a higher price tag.
