Mystery shear bolt breakage on a NH 65 square baler

   / Mystery shear bolt breakage on a NH 65 square baler #1  

DigitalCowboy

Member
Joined
Apr 30, 2013
Messages
41
Location
Pike Co, IL
Tractor
Mahindra 3535
This is my first time out with this "new" $500 ancient baler... mostly it worked. I'd tested it before hand by feeding it some loose hay, tripping the knotters, etc. Once I'd gotten the twine tension right everything seemed good. Greased every fitting I could find and oiled the roller chains with old motor oil.

On one of the first bales I sheared the flywheel shear pin. Found the reason but not the root cause- the "stop"(sorry about the terminology) that comes out to block the plunger from coming back when the needles go in was in and the plunger had hit it. I shut down and replaced the shear bolt but still couldn't manually rotate the flywheel around. I rolled it backwards and gave the needles a little "foot assist" which made the stop come out. I was then able to roll the flywheel and plunger forward. All seemed right. I checked the timing by rotating the flywheel so the plunger arm was 90 degrees straight up. The 3 dots on the drive gear/knotter assembly lined up exactly.... so assuming I did that right the timing is fine. Other causes I read in the manual were suggesting things being dirty/rusty/etc. I crossed my fingers and fired up the tractor and turned on the PTO.... the baler tied off a knot and ran. So I took it back out and made another 30 or so bales without incident.

Then it sheared another bolt- this time the knotter hadn't tripped and the stop was out and a non-issue. I didn't hit anything, there was no foreign object in the bale chamber, I didn't suck up a particularly large wad of grass. Couldn't find one reason why it sheared so I replaced the bolt. Kept baling till I was done. Not a clue why that one happened.

Thought it was worth asking about. I do notice some of the roller chains feel like there's a lot of slop in them... I'm not a baler mechanic but I don't thing they should flop around as easily as they do. The one adjustment I did make before taking it out was to increase the tension on the chain(again sorry for terminology here) that runs across the baler and moves the forks that shove hay into the chamber. They were so loose they'd been clearly slapping against the sheet metal.

Am I likely just having random issues because I'm running a 60 or more year old baler that's had god knows how many bales run through it and stuff is just worn and is just occasionally going to do something goofy? I'm OK with that but I'd hate to tear something up that could have been avoided with some basic adjustment/maintenance or spending a little on a part.
 
   / Mystery shear bolt breakage on a NH 65 square baler #2  
Check the needle brake. It might be when you hit a bump, the needle carriage sags and starts rotating the needles into the bale chamber enough for the plunger stop to engage. I think the needles for a 65 are special to that baler, so if the needle carriage gets bounced down at the wrong time, you could crash the needles, breaking them.

Good luck,
Bill
 
   / Mystery shear bolt breakage on a NH 65 square baler
  • Thread Starter
#3  
Bouncing makes a lot of sense, I was going over a particularly uneven section of ground on slope when the first breakage happened.
 
   / Mystery shear bolt breakage on a NH 65 square baler #4  
Been running a NH65 for 9 or 10 years or so now. Made from 1960 to 1965, Certainly check that knotter brake but I would absolutely verfy timing.

2 things have to be timed on a NH 65:
a) The Feeder carriage with the 4 feeder forks is timed per the book. Once this is set to spec you can pretty much forget about it.

b) The more tricky setting is follow the NH65 manual on the section where it says to trip the knotter and turn the flywheel by hand until the needle tips just enter the bottom of the chamber and then measure the gap between the needle tips to the plunger face to meet book spec dimension. This dimension is critical and if it is not right and within tolerances it will never work. My punch marks for the knotter mechanism on mine were totally useless. Not sure if that pawl engagement mechanism on the end of my knotter shaft on mine is a little worn or if maybe my # of links on that chain is off a little. Regardless I simply played with removing the knotter chain and advancing or retarding that chain so as to get that gap from the needle tips to the plunger face to meet that gap spec. Once you get it to where the gap is always the same and per the book when you repeat the knotter trip say 2 or 3 times in a row and you measure the gap each time and it is consistently the same each time then you got it right regardless of the original punch marks. Feel free to scribe new punch marks if it makes you feel better but they are worthless on a NH 65.

Lastly do not try to use a NH manual for another NH 2-digit model (e.g. 66, 67, 68, 69, etc,) because you found it for free on the internet and think it may be close enough to work. You need the one specific to a NH 65. There are enough unique things that were only done the way they were on a NH 65 such that a manual from one of its bigger brothers will not be sufficient.
 
   / Mystery shear bolt breakage on a NH 65 square baler #5  
Been running a NH65 for 9 or 10 years or so now. Made from 1960 to 1965, Certainly check that knotter brake but I would absolutely verfy timing.

2 things have to be timed on a NH 65:
a) The Feeder carriage with the 4 feeder forks is timed per the book. Once this is set to spec you can pretty much forget about it.

b) The more tricky setting is follow the NH65 manual on the section where it says to trip the knotter and turn the flywheel by hand until the needle tips just enter the bottom of the chamber and then measure the gap between the needle tips to the plunger face to meet book spec dimension. This dimension is critical and if it is not right and within tolerances it will never work. My punch marks for the knotter mechanism on mine were totally useless. Not sure if that pawl engagement mechanism on the end of my knotter shaft on mine is a little worn or if maybe my # of links on that chain is off a little. Regardless I simply played with removing the knotter chain and advancing or retarding that chain so as to get that gap from the needle tips to the plunger face to meet that gap spec. Once you get it to where the gap is always the same and per the book when you repeat the knotter trip say 2 or 3 times in a row and you measure the gap each time and it is consistently the same each time then you got it right regardless of the original punch marks. Feel free to scribe new punch marks if it makes you feel better but they are worthless on a NH 65.

Lastly do not try to use a NH manual for another NH 2-digit model (e.g. 66, 67, 68, 69, etc,) because you found it for free on the internet and think it may be close enough to work. You need the one specific to a NH 65. There are enough unique things that were only done the way they were on a NH 65 such that a manual from one of its bigger brothers will not be sufficient.

I have picked up a NH65 last year but have yet to try to use it. have been to my local dealer several times trying to get them to order a copy of the manual for the NH65. All I have been able to get is a thin 20 or so page booklet. They say they cannot get a shop type manual. Where can I get a copy of a more thorough manual? Is there a part number that you all know?
 
   / Mystery shear bolt breakage on a NH 65 square baler #6  
My guess is slip clutch is stuck tight. How long since drive line slip clutch has been loosened,slipped then tightened enough to hold the tractor torque?
 
   / Mystery shear bolt breakage on a NH 65 square baler #7  
I have a MF #9 baler that is, I'm guessing, 50 + years old. When I bought it, there was an awful lot of slack in all the chains. It worked, but made pretty loose bales (looked like bale purses with long straps when you picked them up), when I first baled my field. I went through the owners manual that came with it, and tightened every chain I could find, and it made a world of difference. I lent it to a neighbor (when his crapped), he turned too tight and bent the pto shaft a bit when it caught on the tractor tire. It still works, but tends to shake a bit. It's never missed a knot since I've owned it, and keep it for a back up now. Not bad for a baler that's as old as I am.
IHMO, tighten and oil all the chains, grease everything you can find, change out all the gear oil, confirm the timing settings, and all will be good for a while.. If yours is like mine, it'll be like a timex watch and keep on ticking.
 
   / Mystery shear bolt breakage on a NH 65 square baler #8  
Plus ..on checking the brake. Double plus on checking the chain tension & knotter timing. Friend had the same issue, timing was off and stop was coming out
 
   / Mystery shear bolt breakage on a NH 65 square baler #9  
I have picked up a NH65 last year but have yet to try to use it. have been to my local dealer several times trying to get them to order a copy of the manual for the NH65. All I have been able to get is a thin 20 or so page booklet. They say they cannot get a shop type manual. Where can I get a copy of a more thorough manual? Is there a part number that you all know?

There is no shop manual for any of the balers that I know of anyway. The " NH 65 compact baler operators manual" for your specific model will have the information you need, but it will not necessarily spoon feed you through anything either. Sometimes you have to read an interpret. The book is thin but has helpful pictures and other critical dimensions listed so 20 to 25 pages sounds about right. Helpful troubleshooting guide in the back for the knotters as well. This book will easily help anyone with some mechanical ability but a non-mechanical greenhorn will struggle.
 

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