NH 276 Baler breaking main drive chain

lastcowboy32

Well-known Member
This has happened twice now this summer. Both times, it's the same cluster of symptoms:

Main drive chain (the big 2060 from the plunger gearbox that drives the pickup, knotters and the tine bar behind the pickup) breaks.

The main shear pin breaks

The knotter shear pin breaks

The knotter drive chain gets stressed (first time it broke, I installed a new chain, second time, it actually moved it's tensioning pulley from the stress, but didn't break the chain)

The tine bar has symptoms: on the right (from the baler's perspective) side where the black, spring-loaded, tine is) The first time, I found that the spring was stretched so far that the tine had flipped right over to point towards the side of the baler opposite from the plunger...it should point down. The second time, the tine broke out completely from the end of the tine bar.


I don't have time today, our daughter is having a house-warming party...but I will post some pictures.

I know how to fix this, I can just replace the tine bar and the tines...put the chain back together and re-time


But....there must be some kind of root cause...


I'm not exactly sure of the conditions; as Pops (my father in law) was running the baler both times...but in both cases, it happened at the end of a piece, either driving across the headland or turning around.
 


What I'm calling the "Tine Bar" is the feeder in the back of the pickup. I'm saying "Tine Bar", because that's what the manual calls it.
 
How are the rollers and tracks that the tine bar runs in? We had problems with those on and old 78. I don't remember the chain breaking though.
 
Many things can cause that including operator errors.
Windrow to big
Ground speed to fast
Sprockets worn out as in the tip of the teeth are sharp instead of flat.
Chain being to long which will throw the timing off.
Bearings going bad which can bind or wobble and cause chain to hang up
Gear box going bad causing thing to bind up.
And probably a number of otherthings
 
Turn it by hand before you put the chain back on to see if anything is binding. Hold your chain up sideways and see how much bend it has in it, it could be worn out. The chain break would probably break all your shear bolts.
 
Definitely check timing , get someone to roll her over by hand so you can follow all
parts operating.
 
(quoted from post at 12:55:23 07/22/18) Turn it by hand before you put the chain back on to see if anything is binding. Hold your chain up sideways and see how much bend it has in it, it could be worn out. The chain break would probably break all your shear bolts.

The big 2060 main drive chain is only a couple of weeks old. I replaced it after the first incident. I bought a brand new 10' length of Timkin chain. It was 140 bucks worth of chain and about another 20 of offset links and repair links. It had better not have any sideways play or stretch to it.

One thing I did find out, though...when I was digging the hay out of the chamber, the very last slab that the baler made had a piece of twine in it, as if it came from a broken bale being re-baled up.

I thought that was curious.

Then, this morning, as we're having breakfast, Pops tells me that he was baling up a broken bale when all hell broke loose.

The last time this happened, a couple of weeks ago was also in heavy windrows.

I'm thinking that there must have been a big slab in there from the broken bale that knocked the spring loaded tine up and over...just like the first time. If that tine gets knocked too hard during the return stroke...the spring can't keep it down...if it gets up and over center, pointed towards the side of the baler opposite the plunger. There's just no room for the tine bar to get all of the way back to return position.

That's my working theory, anyway...

There's no reason this should happen. The tractor still has a gear or two lower to go. We don't have to bale every windrow in 2nd or 3rd gear. 1st gear would be fine, if conditions warranted, and I'll volunteer to hunt down any broken bales in the field and string/shake them out; so we don't bale up any solid slabs during the re-bale process.
 


As nearly as I can tell, the rollers and tracks are OK.



However, the spring that holds the spring-loaded tine; which I just replaced a couple weeks ago during the last incident...was stretched and had its end broken off.


Which is also consistent with the tine bar hitting a big wad of hay or a couple of slabs from re-baling a broken bale during the return stroke.
 


Definitely will. I did this last time as well and had set timing according to the manual. We've done a couple thousand bales since then; so it seems as though I would have seen some kind of symptom from a gross timing error.


I'm thinking that this is some kind of catastrophe...as in the slab from a re-baling a broken bale. Just waaaaaaaay too much hay in the pickup...or something like that...


I've thought about maybe the pickup itself binding...but that's driven by a slip clutch.


I've thought about the knotter binding...but that's on a tiny shear pin. Breaking that shear pin shouldn't have any effect on that massive 2060 main drive chain.


But...the tine bar is driven directly and mechanically through a gearbox...driven by the main 2060 drive chain.... and all of the drive components of the tine bar are just as heavy as the main 2060 chain.


Seems like the tine bar should have some kind of shear pin on it...but having that stop unexpectedly is probably something that's a no-win situation, even if it saves the main drive chain.


Unless the baler is catastrophically jumping timing...but I can't see that happening easily. It's all set by chains and gears...they were all timed and tensioned according to the manual.... I can't see how something like that could easily happen.


The end holding the spring loaded tine broke out of the tine bar this time...maybe that was cracked or on its way out?

It IS a 50 year old baler... stuff happens...
 
I think that you are on to it. Those compressed slabs are hard on everything if they don't get fluffed out some.
 

You need an MF. They are not afraid of broken bales thrown on the windrow. I went to bale for my friend a few days ago when he was having trouble with his baler. He threw a lot of broken bales onto adjacent windrows.
 
I have both a NH270 and a NH276 they have the same feeder system. Recently a guy posted a link about problems with a
NH270. This is a copy of my reply to him.

"I had exactly the same problem with my 270 Baler last summer. There was interference between the tines and the
bracket that holds the pipe. It would occasionally catch , lock up , and break the chain. Apparently it had been
doing this for a long time before I bought the Baler because the chain had been patched in eight or nine places. I
did a lot of research on the problem in the archives of this forum. A former poster ?Steve from new Holland
??suggested taking the pipe completely out of the Baler. His fix was rather controversial. But I found no reason why
the tines should be hitting the pipe , the chain was tight , and the tines were aligned properly , and the carriage
was moving freely in the tracks. So I took the drastic step of pulling the pipe completely out of the Baler. Since
then I?ve Baler several hundred bales and the Baler seems to be functioning fine. The main purpose of the pipe is
keep hay from accumulating high up in the bale chamber. That has not been a problem for me so far. And I also suggest
you put a completely new chain on the Baler tension it properly , and re-time the Baler Carefully."

Now let me add:
This old NH270 baler would bale 300 bales perfectly then suddenly the thing would lock up and break the main drive
chain. Finally as we rolled it over several times by hand to retime it, on one occasion it locked up solid. The
front tine by the chamber was catching on the edge of the bracket that holds the pipe in place. Just one of those
intermitent problems that was hard to find. I also suggest you check the 3 little carriage bolts that hold the pickup
gearbox chain gear on the shaft. 2 of 3 on my 270 baler were loose and worn/rubbing.
 
(quoted from post at 17:52:29 07/22/18)
You need an MF. They are not afraid of broken bales thrown on the windrow. I went to bale for my friend a few days ago when he was having trouble with his baler. He threw a lot of broken bales onto adjacent windrows.

I've done my share of "re-baling" with this baler without any problems. I slow down...maybe even press the clutch if there's a big slab...let the pickup sort of tear the slab apart.

Someone once told my father-in-law that there were certain balers that could pick up a whole bale without even breaking it apart. He swears that he saw one do it once; but he wasn't sure what model it was.

I was like..."Pop...maybe that's true, but maybe don't test our baler to see if it can do it too.."

My brother has a NH 575; which is one of the largest, fastest, most modern NH balers out there. I've been in the wagon piling hay behind that baler...and it's spitting out a bale every six seconds. Needless to say, it 's a good baler.

Even my brother says that the manual for his 575 says that broken bales should be at least spread out a little bit; because the "rotor feed" that it uses to sweep hay from the pickup into the chamber is very efficient and high capacity with loose hay...but it doesn't very much like hard slabs or hard objects.
 
(quoted from post at 21:21:33 07/22/18)
(quoted from post at 17:52:29 07/22/18)
You need an MF. They are not afraid of broken bales thrown on the windrow. I went to bale for my friend a few days ago when he was having trouble with his baler. He threw a lot of broken bales onto adjacent windrows.

I've done my share of "re-baling" with this baler without any problems. I slow down...maybe even press the clutch if there's a big slab...let the pickup sort of tear the slab apart.

Someone once told my father-in-law that there were certain balers that could pick up a whole bale without even breaking it apart. He swears that he saw one do it once; but he wasn't sure what model it was.

I was like..."Pop...maybe that's true, but maybe don't test our baler to see if it can do it too.."

My brother has a NH 575; which is one of the largest, fastest, most modern NH balers out there. I've been in the wagon piling hay behind that baler...and it's spitting out a bale every six seconds. Needless to say, it 's a good baler.

Even my brother says that the manual for his 575 says that broken bales should be at least spread out a little bit; because the "rotor feed" that it uses to sweep hay from the pickup into the chamber is very efficient and high capacity with loose hay...but it doesn't very much like hard slabs or hard objects.

Last cowboy, I just had to throw a little color rivalry in there, LOL. Another situation where my MF proved itself though, was at a certain place in one field, due to shade and high fertility and reed canary grass, the outside double windrow was impossibly huge. Nearly every year as I came around to that spot pulling my JD 336, I would shift down to 1st and slip the clutch in order to "sneak up" on the heavy part. Despite my caution 2 out of three times, it would drag in a huge slug and break the shear bolt. Needing to transition into a thrower and wagons, I got a sweet deal on an MF 224 at an auction. The MF has made it through that spot without ever breaking a shear bolt. It shudders and shakes and causes the tractor to shake but it spits out 2-3 five flake bales. In another situation, I one time while making my way around a tree out in the middle of a field, where there was another tree some 15 feet away, I inadvertently got into two double windrows at the same time. I immediately pressed on the clutch but it was too late. The MF sucked in a huge amount of hay and as I sat there it pushed two bales out one on top of the other!
 
Maybe one of those old Masseys is what Pops saw bale up a whole bale.

I'll have to remember that model number, if I can find one for the right price at auction. I'll let Pops bale with the Massey, and I'll use the NH276.

:)
 
Quote from HayHayHay
*******
Now let me add:
This old NH270 baler would bale 300 bales perfectly then suddenly the thing would lock up and break the main drive
chain. Finally as we rolled it over several times by hand to retime it, on one occasion it locked up solid. The
front tine by the chamber was catching on the edge of the bracket that holds the pipe in place. Just one of those
intermitent problems that was hard to find. I also suggest you check the 3 little carriage bolts that hold the pickup
gearbox chain gear on the shaft. 2 of 3 on my 270 baler were loose and worn/rubbing.
*******
Unquote...

HayHayHay.... you are right on about the mounting bolts. Two weeks ago; when I fixed the first chain break, I noticed that one of the bolts had backed out and had the head nearly worn off by the chain. How long was this going on? I have no clue. When I installed the new chain, I pulled the sprocket off of the plunger gearbox to get good access to the mounting bolts. I extracted the one with the missing head (vice grips) and put in a new bolt with thread locker and a lock washer.

One of the other mounting bolts was also loose...just not far enough out to rub yet. I gave that one the same treatment.

I can say that this exact problem was an issue previously.

It's part of why I put on a brand new chain. I noticed that the rivets in the original chain had all been worn almost flush by rubbing on that mounting bolt.
 
Just tallied up the parts at Messicks...

Somewhere in the neighborhood of 600 bucks, probably more...

Putting the chain back to together is just a few bucks, but this time, the tine bar itself got banged up.

I still have to take the tine bar apart and see what's still good...

but at least 600 bucks...

ouch!
 
I had similar issue on one of my 276 balers, kept breaking the drive chain, broke 2 sprockets, knotter shear bolts, and a couple of the sweep tines into the plunger.... Finally found that one of the bolts
holding the shield bracket behind the sprocket on the gear box for the drive chain, stupid bolt had backed itself out, was occasionally catching on the chain, causing the breaks and the chain reaction of
the other parts breaking. may be worth taking a look see make sure the two bolts are tight. I now check mine every time before I start baling. have had to snug them up a couple times. May or may not be
part of your issue.. good luck, and hope this helps.
 
(quoted from post at 08:50:49 07/24/18) I had similar issue on one of my 276 balers, kept breaking the drive chain, broke 2 sprockets, knotter shear bolts, and a couple of the sweep tines into the plunger.... Finally found that one of the bolts
holding the shield bracket behind the sprocket on the gear box for the drive chain, stupid bolt had backed itself out, was occasionally catching on the chain, causing the breaks and the chain reaction of
the other parts breaking. may be worth taking a look see make sure the two bolts are tight. I now check mine every time before I start baling. have had to snug them up a couple times. May or may not be
part of your issue.. good luck, and hope this helps.

The first time the chain broke and I took it apart, I did notice this. I replaced one of the bolts that had backed out so far that half of the head was worn off.

I put a new one back in with a new lock washer... I haven't looked behind the sprocket yet this time...was too busy diagnosing what parts I need for the tine bar.

Will report back; when I do look behind the sprocket.
 
(quoted from post at 08:50:49 07/24/18) I had similar issue on one of my 276 balers, kept breaking the drive chain, broke 2 sprockets, knotter shear bolts, and a couple of the sweep tines into the plunger.... Finally found that one of the bolts
holding the shield bracket behind the sprocket on the gear box for the drive chain, stupid bolt had backed itself out, was occasionally catching on the chain, causing the breaks and the chain reaction of
the other parts breaking. may be worth taking a look see make sure the two bolts are tight. I now check mine every time before I start baling. have had to snug them up a couple times. May or may not be
part of your issue.. good luck, and hope this helps.

Well, I looked last night. The new bolt that I installed did, indeed back out (after about 1700 bales) far enough where it could be (probably is) the reason for the main drive chain breaking.

All of the other issues were probably, as you said, just the result of a chain reaction of everything (tine bar, knotter, etc) now free wheeling and being out of time, until the plunger stops.

Pictures tomorrow
 
(quoted from post at 08:55:35 07/26/18)
(quoted from post at 08:50:49 07/24/18) I had similar issue on one of my 276 balers, kept breaking the drive chain, broke 2 sprockets, knotter shear bolts, and a couple of the sweep tines into the plunger.... Finally found that one of the bolts
holding the shield bracket behind the sprocket on the gear box for the drive chain, stupid bolt had backed itself out, was occasionally catching on the chain, causing the breaks and the chain reaction of
the other parts breaking. may be worth taking a look see make sure the two bolts are tight. I now check mine every time before I start baling. have had to snug them up a couple times. May or may not be
part of your issue.. good luck, and hope this helps.

Well, I looked last night. The new bolt that I installed did, indeed back out (after about 1700 bales) far enough where it could be (probably is) the reason for the main drive chain breaking.

All of the other issues were probably, as you said, just the result of a chain reaction of everything (tine bar, knotter, etc) now free wheeling and being out of time, until the plunger stops.

Pictures tomorrow

That the bolt keeps backing out on you as well as others makes it sound like a design problem. The threads in the hole may have opened up so that it doesn't get adequately tight, or it may strip right out before it can be adequately tightened. It may need a Helicoil or equivalent. Or just eliminate the shield.
 
That is why I check that on mine every day before starting. most of the time, it is tight, however.... not letting that stupid bolt cost me hundreds again.
 
That the bolt keeps backing out on you as well as others makes it sound like a design problem. The threads in the hole may have opened up so that it doesn't get adequately tight, or it may strip right out before it can be adequately tightened. It may need a Helicoil or equivalent. Or just eliminate the shield.[/quote]

Unfortunately, removing the shield isn't an option. The shield is very heavy, it's something like 1/8" metal, and the main drive chain tensioning pulley and it's tightening mechanism are all mounted to it.

Helicoil, Loctite, Tac weld the head of the bolt... check the bolt every time we bale....

Either one or a couple of those solutions will need to be applied.
 

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