nh 68 knotter question

[Hogleg]

What causes the billhook to leave the knot on the hook depending on hay windrow density. In dense hay it hooks up 100%. In a light windrow we can go all day...

Sharpened the knives, but no effect.

Is it the tension adjustment on the billhook? it seems that more hay getting jamed into the chute affects how the knotter executed the knot. Is the heavier hay pulling the knot apart before the billhook has completed the revolution or is the billhook not holding firm enough?

This baler was flawless for the first 300 bales this year. (We only bale around 100 at a time). But now has progressed from occasional failures to 100%. I found that the billhook tension nut is loosening as it runs, will fix that.

Bale tension at the back of the chute is pretty light. Bales are not packed tight.

What else?

Reading the manual but not getting it...

John

 

[retired farmer]

Check to see whether the stripper arm is slightly rubbing on the bottom of the bill hook when it comes across and cuts the twine. It should just drag across with moderate force. To do this, raise the knotter up enough so the stripper arm contacts the bottom of the bill hook and then move the stripper across the hook with your hand. If it doesn't drag, then hit the top part of the stripper with a big hammer once or twice. This will bend the arm into the bill hook. Just be careful not to break anything. You may also have too much tension on the bill hook spring.

 

[Hogleg]

Thanks for the reply!

It is rubbing across the billhook but not what I would call hard. The knot hangs up on the very end of the billhook with the knot made around the end of the hook. Is the stripper needing to rub it more firmly?

John

 

[RodinNS]

The wiper/striper arm is not wiping the knot off the hook. Make sure the wiper makes fairly firm contact with the hook about 11/16" from the tip of the bill hook and maintains that contact to the tip of the hook. If it's NOT maintaining contact throughout that arc then the hook is either bent or worn out. Replace the bill hook(s). They're probably about 100 bucks each.

Rod

 

[Tom in TN]

Hogleg,

I'm not a knotter expert by any stretch of the imagination, and
what I'm about to mention doesn't seem like it would be your
problem, but here goes anyway.

My NH 273 Operator's Manual in the troubleshooting section
talks about the billhook developing a sharp point on the end of
the hook from the twine running across it. It mentions that the
billhook should have a rounded tip on it where the ends of the
billhooks touch each other during the knotter cycle, but that the
rounded tip can develop a sharp tip from wear.

Now, here's why I doubt this is your problem, the typical failure
that this will cause is that the billhook won't hold the twine
firmly enough when the knotter rotates, consequently a knot
won't form. But, I wonder if it's possible that your billhook has
developed this sharp point so the the knot is getting caught on
the sharp tip and is not allowing the stripper to pull it off the
billhook.

Probably not, but it might be something else to look at.

Good luck. Knotters can be really frustrating when they're not
working right.

Tom in TN

 

[old]

When the twine knife goes across the bill hook the area that rubs has to do so in such a way you can feel it doing so and if it does not you need to adjust if so it does. As in takes a bit of push by hand to move it not just an easy swing by

 

[RodinNS]

I've had hooks wear such that the heels are fairly normal but the tips are either worn away or bent. I fought this exact problem on my Ford for several days before I figured it out... The radius of the hook is gone and the wiper loses contact with the tip and fails to wipe the knot. I'm not too sure mine wern't actually bent... Regardless, two new bill hooks solved the problem.
I'd also endeavour to make sure I got the poly type hooks. Even with new hooks I had to grind the releifs out of the hook fingers so they'd close tighter...

Rod

 

[Hogleg]

Going to fool with it more today or tomorrow. When I last looked at it, the wiper moved easily from side to side across the billhook so I am pretty sure that is the problem. I bought this baler 2 years ago and it ran good up to now, but we only do 300-400 bales a year. The billhooks are bright chrome and shiney. I found some old ones in the tool cubby so I bet they were replaced in the last few years and perhaps the wipers were not re-bent properly. There is no visible wear on the billhooks that I can see.

Anyway, this sounds like the right solution...

John

 

[RodinNS]

Bill hooks generally don't appear worn. Bend the wipers so that they contact the heel of the hook 11/16" from the tip. You want a modest amount of drag at that point and it needs to follw this same arc through to the tip of the hook. If the hook receds away, THEN you know it's worn. Also make sure that you bend them in such a way that you don't move the twine knife closer to the knotter frame....
One other thing not mentioned... the twine finger on th ehook could be took tight. If it is too tight it will retain the knots on the hook. If it's too loose it won't hold the ends to make a knot so you need to find a happy medium...

Rod

 

[Hogleg]

Just took a look. The wiper is making good contact all the way across the billhook. I did notice that the nylon lock nut can be moved with finger pressure. Going to replace it. Maybe it is working itself out as it is baling... I had tightened it in the field and it was baling, then went to bigger windrows and it quit tying. Guessing that maybe the pressure is too much. Going to go out and fiddle with that setting on some hay to see if I can get it to tie.

Will post back later..sure learning a lot.

John

 

[Anonymous-0]

First thing to remember is no two fields of hay are the same. Even a single field is going to change throughout the day. A baler is not a set-it-up-and forget it piece of machinery, you're going to have to fiddle to get good bales. That's why consistent windrows are so important.
Having said that, there are three adjustments that affect the knot hanging. The wiper, which has been covered here in good detail, the twine disk, or those notched plates the twin passes through that grips the twine so the knot can be tied, and the bill hook cam, which is that spring/nut combination you were referring to. All three have to be singing in harmony to get perfect bales.
If the twine disks are too tight in heavy hay, it will stop the knot from being stripped. If the bill hook cam adjusting nut is too tight, knots may hang. The bill hook cam adjusting nuts should be able to be adjusted with your fingers, without need for a wrench.

 

[Hogleg]

Understood.

I got it knotting properly in the very light hay that I had left on a field. 5 knots out of 5. Need to run some more hay thru it to make sure.

One think I noticed is that the twine disks are pretty sloppy. Lots of wallered out holes and the return spring is loose. Does that mechanism have to be pretty firm also?

John

 

[Northvale - PA]

I run JD 336"s but I understand they have similar knotters. 1 trick I do 2x per day is spray WD-40 on the bill hook roller and wiper arm roller. These small steel rollers get hay dust in them, sieze up, slide instead of roll then get flats worn on them. Make sure they roll free at all times and are round. Otherwise the knotter gets way out of adjustment.

 

[RodinNS]

Are the wiper arm rollers (in the cam) even free? Remove the wipers and inspect them. Make sure the brass roller is free and not worn flat on one side.... I also wouldn't worry about backing the bill hook finger tension off until it pulls the twine OUT of the finger when it's forming the knot... then tighten it up just a bit. Remember... you have them hanging on the hook indicating it could be too tight.
I would NOT bugger with the twine disc timing just yet. If you have it forming the knot that suggests to me that it's correct. Incorrect twine disc timing generally results in the #2 string not getting picked up properly in the tie cycle and it drops out of the disc when the next cycle starts IF it hasn't already been pulled away by twine tension while forming the new bale.
Also make sure the twine fingers on top of the bale chamber are working correctly and pulling the twine back when the needles come up.

Rod

 

[JDseller]

Just flip the knotter up and see how hard the wiper arm goes across the bill hook. It should drag 5-10 lbs of force. You adjust it by bending the wiper arm a little. I have found a pipe wrench works well for this. You clamp the jaws on the arm and then bend side ways not the normal direction you would use the wrench. Also check and see how well the radius matches the outside of the bill hook. If the wiper arm is worn it will not mate the billhook very well. I just take a round file and model it to match the billhook. After you have the drag set make sure the wiper arm will come back across the billhook. IF you have too much drag the wiper arm will hit the face of the billhook on the return cycle. Just take your time and you can get it done. Get a NH operators manual if you don't have one.

Also check the hay dog springs too. In heavy hay broken/weak springs can make the knotter act up.

 

[Anonymous-0]

I think we might have a nomenclature problem here. The twine disks are in the knotter frame itself. They have a little notch that the the twine fits in as the bale is created. The notched disk turns between "Ace of spades" shaped plates, holding the twine firm as the billhook creates the knot, and the wiper and knife cuts off the ends. If that disk is too tight, the twine is held too firmly, the knot will be too tight and hangs on the billhook. The knot as it is properly made is actually not that tight around the billhook so the wiper can strip it off. The action of the bales expanding as they move through the chute is what tightens them up. That's why I think you're having you're problem in heavy hay. The bales are tightening the knot before it's ready to slide off the billhook. In light hay, the flakes are not compacted as tightly.

When the knot is made, the needles come up and replace the twine in the little notch. If the twine is laying in the notch center, or down toward the inside corner, the timing is probably good. If the timing is off, the free ends of the knot will be of different lengths, or only one string will be knotted. The timing is adjusted by loosening the nut at the bottom of the worm gear and tapping it one way or the other. The tension is controlled by about a 3" long, straight "finger" spring.

The disks on top of the bale chamber, which are often sloppyloose and have a spring that hooks to the knotter frame, are the twine fingers. those catch and bring the twine into alignment so the billhooks can grab them.

 

[Hogleg]

These last 2-3 posts have been quite informative.

Where I am now is that the knot forms correctly all the time on the left knotter. It has never messed up. The right knotter appears to be older and is more worn. It is now making a knot almost every time in light hay. The minute we hit a heavier part, it will start missing. The string on top of the bale will have a formed knot loop.

The wiper appears to press firmly on the billhook and moves across the billhook maintaining pressure. I did discover that the brass ball that rides the cam gear eccentric path is hard to turn but does not appear to have a flat spot. On the large lobe of the cam gear eccentric path, it has a very deep groove worn, where the left knotter has a shiny mark but no groove. This groove is probably 1/8 to 3/16 deep (maybe more). Here is a pic.

Is it perhaps possible that as "Our Farmer" said, the knot is forming on the billhook, but the wiper may not be pushing it off fast enough, due to the wear on the knotter so that the knot gets pulled apart before fully wiped? Can this groove be welded up and re-contoured to correct the wear?

Am I on the right track? Maybe it is time to find a knotter on a parts baler? Yes, I know it is dirty. I did not get a chance to blow it off after the last baling experiment.

Would sisal twine be more forgiving given this wear? I am using Tytan 170 twine now.

On edit - WOW - new cam gear is $343 from NH! That is almost twice what I paid for the whole darn baler!

2nd edit - this post describes the cam gear lobe wear issue pretty good. Bet this is the problem. Going to play with it more in the afternoon and have my daughter spin the flywheel during the knoting to observe the wiper/knife motion.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=implment&th=143477>

John