will-max dairy
Well-known Member
I made a new thread about this, because it's something that is common and almost always overlooked on old NH balers. The preseason is when to think about this... as opposed to what happened to me... we went through an entire summer of "random mystery miss" knots with our baler... and we corrected this problem in the fall, mostly by random chance. The only way I knew this cam was worn, was I noticed the roller that rides on it (on the twine finger actuator arm) was frozen. When I went to our scrap baler to scavenge another roller (since this was a Sunday), I noticed the roller on our scrap baler was great. Nice and "rolly..."
Just by chance, I caught a glimpse of the cam on the scrap baler and noticed that it stood 1/4" to 1/2" taller than the one on the baler we were using, and had a much more defined "ledge" where the high piece ended. This is an issue, because the height of the tip of the cam determines the arc swing of the twine fingers. If the twine fingers don't swing through enough of an arc, "twine 1" and "twine 2" are not put together, so that they can both be grabbed by the bill hook. The nice sharp drop off makes the twine fingers retract quickly... so they get out of the way and let the twine move freely as the billhook rotates.
(parenthetically... if you're running on one old twine finger actuator return spring... you can always install a second one for redundancy... I always run two. It makes the twine fingers nice and snappy, and immune to a single spring breakage...but... it also puts lots of pressure on the roller; so you really need to make sure it rolls, or you'll wear down your cam to nuthin' in a hurry, like mine did...)
Our son-in-law used a piece of cardboard to copy the correct cam shape. He then used the MIG to build up the cam, then grind and polish to the correct shape. It made a big, big difference. No more random groups of three to five bales in a row being broken while we were baling.
If you can... take a look at this cam and the roller... make sure the roller rolls... and make sure the cam has about a 1/2" tall tip on it with a nice steep drop off. Also... make sure the roller is hitting the cam...
If you don't have a scrap baler around with a good cam to use as a profile, it would seem that a dimensioned drawing could be found somewhere.
Happy baling!
Just by chance, I caught a glimpse of the cam on the scrap baler and noticed that it stood 1/4" to 1/2" taller than the one on the baler we were using, and had a much more defined "ledge" where the high piece ended. This is an issue, because the height of the tip of the cam determines the arc swing of the twine fingers. If the twine fingers don't swing through enough of an arc, "twine 1" and "twine 2" are not put together, so that they can both be grabbed by the bill hook. The nice sharp drop off makes the twine fingers retract quickly... so they get out of the way and let the twine move freely as the billhook rotates.
(parenthetically... if you're running on one old twine finger actuator return spring... you can always install a second one for redundancy... I always run two. It makes the twine fingers nice and snappy, and immune to a single spring breakage...but... it also puts lots of pressure on the roller; so you really need to make sure it rolls, or you'll wear down your cam to nuthin' in a hurry, like mine did...)
Our son-in-law used a piece of cardboard to copy the correct cam shape. He then used the MIG to build up the cam, then grind and polish to the correct shape. It made a big, big difference. No more random groups of three to five bales in a row being broken while we were baling.
If you can... take a look at this cam and the roller... make sure the roller rolls... and make sure the cam has about a 1/2" tall tip on it with a nice steep drop off. Also... make sure the roller is hitting the cam...
If you don't have a scrap baler around with a good cam to use as a profile, it would seem that a dimensioned drawing could be found somewhere.
Happy baling!
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