In order to form a properly tied bale knot, the first end of the knot must be held firmly in the twine disk, the needles must bring the other end of the twine up thru the knotter frame, the tucker fingers must push the twine into the notch in the twine disk, the twine disks must turn and hold it, the bill hook must rotate, the billhook jaw must open and capture the two twine ends, the jaw must close as the bill hook rotates further, the wiper arm must scrape the newly formed knot off the billhook foot and the cutoff knife must sever the twine downstream of the newly formed knot without tearing it out of the twine disk.
Any failures in this process will lead to a 'not a knot' or busted knot condition. The twine box pull tension should be about 10 lbs for each side. The needles should slightly touch the knotter frame as they come up to keep them from vibrating causing the twine length to slackren, The tucker fingers should just barely clear the needles as they rotate, the needles must come up together far enough for the twine to arrive in the disk notch, the twine disk must hold firmly both ends of the twine, the billhook jaw must open far enough to accept the twine pairs, the jaw tension should also be about 10 lbs, the bill hooks (as in duck bill shape, yes they are cast billet) must rotate in the right sequence, and the wiper arm actually scrapes the newly formed knot off the billhooks. Its not close, it must be a full contact scrape with a screech.
Look for too loose or too tight twine box tension, a broken tooth on the intermediate gear, a tucker finger that is late because of a twisted shaft, a twine disk clamping force that is weak, a billhook jaw not opening far enough (or fully closing) beause of a missing or work billhook jaw roller, a wiper arm missing its mark, or a dull knife that is yanking the knot loose and tearing it apart.
Don't repeatedly run the machine without hay or straw in it because there could be multiple attempts to make knots which will jamb up the billhook jaws and break them.
Nearly ALL missed ties are from tucker finger action out of adjustment or sloppy, but worn or broken springs that regulate holding tension can be major causes, too. If the wiper arm balls are worn flat because they are frozen on their shafts and not rotating, then they won't have enough travel to get the job done. It now all depends on what the condition of the twine ends is at your bad knotter, Pictures would sure help. How about a video of the roll by hand action?
Empty the straw and twine from the machine, trip the knotter drive and rotate the flywheel over by hand no more that 5 degrees per second to watch all this activity. Its a bit jerky because of all the mechanically timed engagements but its all there to see happen, in order and in slow motion.
