Snapping Flywheel Shear Bolts on a New Holland 276 Super Baler

[TrickyT]

Have been helping the brother in law do some small bales. He is using an MF390 with a New Holland 276 Super Baler.

I would anticipate we have done 10 acres and 600 bales, but we keep snapping the flywheel shear bolt.

As fat as we are aware everything it set up correctly.

• PTO turning at 540, with the baler doing 70-75 strokes per minute (book says maximum SPM is 80)
• There is plenty of hay in the windrow.
• Ground speed with SPM means it is doing about 10-12 strokes per small bale.
• Everything greased up and free.

Initially it seemed to do it after turning right on the headland, so we go to the stage of turning off the PTO, which didn't help or slowing down the PTO but it still happened.

Then it has started happening when going in a straight line.

We have checked the bale tension and they are not over tight.

Probably done 10 shear bolts in total. Anyone got any advice?

Trevor

 

[db9go]

Have been helping the brother in law do some small bales. He is using an MF390 with a New Holland 276 Super Baler.

I would anticipate we have done 10 acres and 600 bales, but we keep snapping the flywheel shear bolt.

As fat as we are aware everything it set up correctly.

• PTO turning at 540, with the baler doing 70-75 strokes per minute (book says maximum SPM is 80)
• There is plenty of hay in the windrow.
• Ground speed with SPM means it is doing about 10-12 strokes per small bale.
• Everything greased up and free.

Initially it seemed to do it after turning right on the headland, so we go to the stage of turning off the PTO, which didn't help or slowing down the PTO but it still happened.

Then it has started happening when going in a straight line.

We have checked the bale tension and they are not over tight.

Probably done 10 shear bolts in total. Anyone got any advice?

Trevor

Have you checked the needle timing as that controls the ram stop. have you checked the needle brake as if that is loose it will let the needles drop and put the the ram stop in.
What is the bale chamber like is it shine or rusty if it is rusty clear all the hay out as a rusty chamber can make it hard to bale as the increase bale tension is to much for the shear bolt
Are you using the correct shear bolt.

 

[Exfarmer]

Probably needle slip, just a little will engage the needle lock which will shear the bolt. Check the needle brake.

 

[Exfarmer]

Probably needle slip, just a little will engage the needle lock which will shear the bolt. Check the needle brake.

Posts crossed!

 

[TrickyT]

Have you checked the needle timing as that controls the ram stop. have you checked the needle brake as if that is loose it will let the needles drop and put the the ram stop in.

• I assumed it was all ok as it only happened occasionally, but I will check as the brother in law said it was all ok, but I think I need to read the manual to double check!

What is the bale chamber like is it shine or rusty if it is rusty clear all the hay out as a rusty chamber can make it hard to bale as the increase bale tension is to much for the shear bolt

• I don't actually know as I have never looked.

Are you using the correct shear bolt.

• Yes, correct shear bolt is being used.

Trevor

 

[Exfarmer]

Just thought , wear in the ram guides , are the hay knives catching?

 

[Daveh]

How sharp is the knife, is there any side play in the ram or any float in the flywheel or wear in the inserts that hold the shearbolts?

 

[Will 1594]

Have you looked at the bushes in the flywheel , and hub it runs on ,

 

[davidroberts30]

Have you looked at the bushes in the flywheel , and hub it runs on ,

This^

 

[db9go]

Have you checked the needle timing as that controls the ram stop. have you checked the needle brake as if that is loose it will let the needles drop and put the the ram stop in.

• I assumed it was all ok as it only happened occasionally, but I will check as the brother in law said it was all ok, but I think I need to read the manual to double check!

What is the bale chamber like is it shine or rusty if it is rusty clear all the hay out as a rusty chamber can make it hard to bale as the increase bale tension is to much for the shear bolt

• I don't actually know as I have never looked.

Are you using the correct shear bolt.

• Yes, correct shear bolt is being used.

Trevor

What is ground like is smooth or bumpy if its a bit bumpy it could be the needle brake as it only need to move a small amount and it will bring the ram stop.
When you empty the chamber see if there is a build up of chaffy material in the lower corners as that adds to make it harder for the ram to push the bale out that normally happens with a rusty chamber and seeds

 

[Dry Rot]

Are the holes the shear bolt go through deformed in any way? If someone has used a bolt of the wrong degree of hardness, the hole can get damaged causing it to act like a pair of shears. Examining a broken bolt carefully might reveal something. Also, are the bolts tight enough? Nyloc nuts?

 

[chaffcutter]

If the broken bolt is bent rather than a clean break, the bushes are worn as said previously, this is just as important as the checks on timing etc, when we were baling 15k bales a year we used to use 2 sets a year

 

[Cowabunga]

All the above plus, are you driving too fast? Is the swath lumpy and prone to be pulled in from a distance? Swath made by a Vicon Acrobat or similar wheel rake?
Most likely, in my opinion, is a loose knotter brake or shear bolt bushes that have rounded edges through wear over the years.

Having said that, it may be something else entirely.

 

[Dave.p]

All the above plus, are you driving too fast? Is the swath lumpy and prone to be pulled in from a distance? Swath made by a Vicon Acrobat or similar wheel rake?
Most likely, in my opinion, is a loose knotter brake or shear bolt bushes that have rounded edges through wear over the years.

Having said that, it may be something else entirely.

Check the slip clutch on the flywheel, slacken off the bolts over the springs and make sure the plates aren't stuck together by engaging the pto and letting it slip, then tighten again making sure the springs have a gap between them.

 

[Cowabunga]

Check the slip clutch on the flywheel, slacken off the bolts over the springs and make sure the plates aren't stuck together by engaging the pto and letting it slip, then tighten again making sure the springs have a gap between them.

Yes. Should be slackened off, slipped a bit and retightened to spec at the start of every season. Often forgotten. This lets the clutch slip slightly at every stroke when under heavy load which takes the peak load off the shear bolt and tractor PTO.

 

[bobk]

My 276 had a penchant for breaking shear pins , it was cured by loading it up and taking it to the scrapper , pos .

 

[Goweresque]

My brother in law had a NH570 which consistently did this, the ram stop was always just about to catch the ram, he was always doing shear bolts. We managed to adjust the timing to get it to run better but would still do a shear bolt once or twice in a 10 acre field. He finally solved the problem when he replaced the knotter drive chain, it had stretched and meant the timing was impossible to get 100% right. Since replacing that its run like a sewing machine.

 

[TrickyT]

Many thanks for all the advice. Plenty to go on, will feed back what i find.

I know we have not done anything with the clutch, so that will be the first thing. I did think that if the going got tough, then the clutch should slip before the shear bolt went?

Trevor

 

[davidroberts30]

Many thanks for all the advice. Plenty to go on, will feed back what i find.

I know we have not done anything with the clutch, so that will be the first thing. I did think that if the going got tough, then the clutch should slip before the shear bolt went?

Trevor

Do you have a manual for the baler?

 

[essexpete]

As others have suggested check the shear bolt holes. If the ground is rough then you can bounce the needles if the brake not adequate. It strikes me that it cannot be far out. If you do adjust make a small adjustment one at a time.
Do the slip clutch as said above.
You do need the moving and static knives sharp and fag paper width as they pass. With an empty chamber use a bar on the ram to see if the gap between the blades might be widening as material is pushed in.
Don't forget to make sure the baler cannot free run when you are fiddling about with the ram.