{"id":1177,"date":"2026-07-29T03:28:12","date_gmt":"2026-07-29T03:28:12","guid":{"rendered":"https:\/\/foragebaler.com\/?p=1177"},"modified":"2026-07-29T03:28:12","modified_gmt":"2026-07-29T03:28:12","slug":"square-baler-not-tying","status":"publish","type":"post","link":"https:\/\/foragebaler.com\/hi\/square-baler-not-tying\/","title":{"rendered":"Square Baler Not Tying"},"content":{"rendered":"
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Troubleshooting Guide \u00b7 All 9YF Models \u00b7 12 Causes Covered<\/p>\n
A square baler that stops tying \u2014 or ties intermittently \u2014 loses you crop, time and revenue during the narrowest weather window of the season. Every miss-tie has a specific mechanical or operational root cause. This guide covers all 12 causes, organised by diagnostic zone, so you can identify the exact problem and fix it without guesswork.<\/p>\n
Covers: twine path \u00b7 tension discs \u00b7 bill hooks \u00b7 needle timing \u00b7 cam wear \u00b7 PTO speed \u00b7 one-side vs both-side misses<\/p>\n
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The knotter system has four distinct zones \u2014 each responsible for a specific part of the tying cycle. Answering five quick questions locates your fault zone before you open a single cover, saving the time lost to checking the wrong components first.<\/p>\n
Every bale?<\/strong> \u2192 Mechanical fault (permanent).<\/p>\n Intermittent?<\/strong> \u2192 Timing, power or crop density issue.<\/p>\n<\/div>\n One side only?<\/strong> \u2192 Fault isolated to that knotter unit.<\/p>\n Both sides?<\/strong> \u2192 Shared component \u2014 PTO speed, main drive, or twine feed.<\/p>\n<\/div>\n Loop present on bale?<\/strong> \u2192 Knife did not cut \u2192 Cause 7 or 9.<\/p>\n No loop at all?<\/strong> \u2192 Needle did not deliver twine \u2192 Cause 8 or threading error.<\/p>\n<\/div>\n Twine wrapped loosely?<\/strong> \u2192 Tension problem \u2192 Cause 4 or 5.<\/p>\n Twine pulled through?<\/strong> \u2192 Bill hook not holding \u2192 Cause 6.<\/p>\n<\/div>\n In heavy windrow only?<\/strong> \u2192 Power deficiency \u2192 Cause 11 or 12.<\/p>\n Regardless of crop?<\/strong> \u2192 Mechanical fault, not load-related.<\/p>\n<\/div>\n<\/div>\n <\/p>\n Zone 1 problems are the easiest to fix and the most frequently overlooked. Always check the twine path first before spending time on the knotter mechanism \u2014 a mis-threaded or worn guide causes symptoms that look identical to knotter faults.<\/p>\n The twine does not follow the exact path specified in the operator manual. A single wrong guide eyelet produces incorrect tension variation at the knotter entry point \u2014 the loop forms incorrectly or not at all, causing a consistent miss from the moment the new spool is threaded.<\/p>\n<\/div>\n Remove all twine from both knotters. Using the threading diagram in the operator manual \u2014 not memory \u2014 re-thread both sides from spool to needle eye. Confirm each guide eyelet is correctly used and the twine does not cross over itself at any point. Run 5 test bales before returning to normal speed.<\/p>\n<\/div>\n<\/div>\n<\/div>\n Metal guide eyelets wear a groove into their inner surface from seasons of twine running through them at speed. A grooved eyelet catches the twine on each bale cycle, creating friction that disrupts tension uniformity and can cut through the twine after enough repetitions. Burrs from field debris impact cause the same problem.<\/p>\n<\/div>\n Run a finger around the inside of every guide eyelet in the twine path. Any groove, rough edge or burr felt by touch will damage twine over repeated cycles. Smooth minor roughness with fine-grit emery cloth. Replace any eyelet with a groove deeper than 0.5mm \u2014 the replacement cost is minimal and the symptom is permanent until the eyelet is changed.<\/p>\n<\/div>\n<\/div>\n<\/div>\n A spool stored in damp conditions can have an inner core that softens and collapses under the weight of the twine above it. As the spool unwinds near the core, the collapsed core creates an irregular feed rate \u2014 the twine feeds in bursts and then goes slack, producing tension variation that the knotter mechanism cannot compensate for.<\/p>\n<\/div>\n Remove the spool and check that it rotates freely in the holder with light finger pressure. If the core feels soft or deformed, replace the spool \u2014 do not attempt to continue with a damaged spool. Prevent this issue by storing twine spools in a dry, covered location away from ground contact. Never leave spools loaded on the machine between seasons.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n <\/p>\n Zone 2 faults are in the knotter unit itself \u2014 the tension discs, bill hook, knife and wiper arm. These are the most common causes of miss-ties in machines that have been in use for more than one season without a full knotter service.<\/p>\n Tension discs control how much resistance the twine meets as it feeds through the knotter. When set too loose, the twine feeds too freely \u2014 the loop that forms around the bill hook is large and slack rather than snug. The bill hook cannot grip a slack loop reliably, and it slips off before the wiper arm strips the knot.<\/p>\n<\/div>\n Increase the tension disc spring pressure by one half-turn on the adjustment nut. Test with 5 bales. If the loop is still large, increase by another half-turn and retest. The target loop should be firm and close-fitting around the bill. Both tension discs must be set equally \u2014 unequal tension produces one clean knot and one loose knot per bale cycle.<\/p>\n<\/div>\n<\/div>\n<\/div>\n Over-tightened tension discs place the twine under continuous tension throughout the bale cycle. When the knot tightens around the bale during ejection, the combined tension from the disc and the bale compression load exceeds the knot strength of the twine. This is particularly common when higher bale density settings are used without a corresponding upgrade in twine knot strength rating.<\/p>\n<\/div>\n Reduce tension disc pressure by one half-turn. If the twine continues to break at the knot and the discs are already at minimum, the twine strength rating is insufficient for the density setting \u2014 upgrade to a higher-rated twine (minimum 130kg knot strength for high-density bales above 28kg). Do not reduce bale density to match weak twine; change the twine to match the density.<\/p>\n<\/div>\n<\/div>\n<\/div>\n The bill hook tip captures the twine loop and holds it while the wiper arm strips the knot. A bill with a worn or chipped tip no longer has the geometry needed to hold the loop securely \u2014 the loop rolls off the bill rather than being held through the stripping action. A bill that is correct in sharpness but misaligned in angle presents the wrong capture surface to the incoming loop.<\/p>\n<\/div>\n Remove the bill hook and inspect the tip face. Run a fingernail across the curved tip face \u2014 any flat spot, chip or rounding indicates the bill needs replacement. Check the bill hook angle against the specification in the operator manual using a protractor or the gauge tool if supplied. Replace both bills as a pair whenever one shows wear \u2014 running a new bill against a worn bill produces uneven knots even if both sides appeared to tie during a quick test run.<\/p>\n<\/div>\n<\/div>\n<\/div>\n The knife blade must cut the twine cleanly after the knot is stripped. A dull knife does not cut \u2014 it pulls and saws the twine over several millimetres before it separates. This pulling action applies a sideways force to the finished knot while it is still on the bill, rotating the knot out of position before stripping is complete. The result is a malformed or loose knot that does not hold under bale compression.<\/p>\n<\/div>\n Replace both knife blades at the start of every season as routine maintenance \u2014 the cost is low and a sharp blade is the starting point for reliable knotting. Mid-season replacement is needed if ragged tails appear before the season end. After replacement, verify the blade-to-twine-guide clearance is within specification \u2014 a blade positioned too far from the guide cuts at the wrong point in the cycle and produces erratic results even when sharp.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n Timing problems are the trickiest category because the symptoms are indistinguishable from Zone 2 faults until the mechanism is observed in slow motion. A timing fault means the knotter is mechanically correct but the needle delivers twine at the wrong moment \u2014 outside the capture window of the bill hook.<\/p>\n The needle must travel a precise arc to present the twine at the exact position where the bill hook can capture it. A bent needle arm \u2014 caused by a blockage impact, a stone in the chamber or a plunger strike \u2014 changes the tip position at the capture point by just a few millimetres. This small deviation is enough to cause the bill to miss the presented twine on every cycle.<\/p>\n<\/div>\n Cycle the machine slowly by hand (PTO disconnected) and watch the needle tip at its furthest travel point. The tip should align exactly with the bill hook face position per the specification diagram in the operator manual. Any lateral offset indicates a bent arm. Straightening a bent needle arm is not recommended \u2014 the metal is work-hardened and the straightened point is weaker than the original. Replace the needle arm and recheck the tip position against specification before resuming operation.<\/p>\n<\/div>\n<\/div>\n<\/div>\n The cam follower arm rides on the cam lobe surface and translates the cam rotation into needle movement. As the follower tip wears, the effective radius at the tip changes \u2014 the follower lifts slightly later on each cam rotation than it should. This timing delay moves the needle delivery point outside the bill hook capture window, producing a miss. The delay worsens as wear progresses, which is why timing faults start as occasional misses and become consistent failures over time.<\/p>\n<\/div>\n Remove the cam follower arm and measure the tip radius against the specification in the operator manual using a caliper. Wear beyond the minimum specification requires replacement. Also check the pivot bearing on the follower arm \u2014 a worn pivot bearing introduces lateral movement into the follower tip, which compounds the timing error even if the tip radius is within specification. Replace both together when either is at the wear limit.<\/p>\n<\/div>\n<\/div>\n<\/div>\n The cam lobe peak is what drives the follower to its maximum travel position, which corresponds to the needle delivering twine at the correct depth into the bill capture zone. A polished flat section on the cam lobe peak means the follower no longer reaches its maximum travel \u2014 the needle stops short of the full delivery position and the bill misses the twine. Cam wear at the peak is accelerated by inadequate lubrication of the cam surface.<\/p>\n<\/div>\n With the PTO completely disengaged and the machine stationary, rotate the main knotter shaft slowly by hand and watch the follower travel. On a good cam, the follower lifts smoothly to a distinct peak then returns smoothly. A flat spot produces a hesitation \u2014 the follower pauses or barely rises at the peak position. Measure the cam lobe height at the peak against the operator manual specification. A worn cam requires replacement \u2014 the cam is a precision-machined part and should not be welded up or shimmed as a field repair.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n <\/p>\n Zone 4 causes are unique because the knotter mechanism is entirely correct \u2014 the fault lies in the operating conditions. These are the most commonly misdiagnosed causes, because operators who have already checked the knotter without finding any faults do not consider the tractor or the windrow as the source of the problem.<\/p>\n The knotter timing is calibrated at 540rpm PTO speed. Every cam position, needle travel and bill hook rotation is timed to a specific phase of that rotation speed. When the tractor drops below 540rpm under load \u2014 because the tractor is undersized for the baler or the windrow is particularly dense \u2014 every timing relationship in the mechanism shifts. The needle arrives at a different phase of the bill rotation than designed, and the capture fails.<\/p>\n<\/div>\n Monitor tractor engine RPM on the instrument display throughout the baling session. If engine RPM is decreasing during bale cycles \u2014 particularly at the peak compression point \u2014 reduce forward speed until the engine maintains rated RPM without laboring. If the tractor cannot maintain rated speed at any practical forward speed, the tractor is undersized for the baler or the crop conditions. A correctly matched square baler<\/a> should operate at 60\u201380% of tractor PTO rated output in standard conditions, leaving reserve for density peaks.<\/p>\n<\/div>\n<\/div>\n<\/div>\n A tractor at 100% of its rated PTO output in an average windrow section has zero reserve for the brief peak compression load when the plunger reaches maximum stroke. In heavy windrow sections \u2014 merged windrows, areas of higher crop yield, or sections where the previous rake pass created a thicker accumulation \u2014 the peak load spikes above the tractor rated output for 0.5\u20131 second. This brief spike drops PTO speed enough to shift knotter timing and produce a miss, even on a tractor that is nominally adequate for the baler model.<\/p>\n<\/div>\n Reduce forward speed when approaching visibly heavier windrow sections \u2014 the higher material volume per plunger cycle creates the load spike. Alternatively, improve windrow consistency through raking adjustments that produce a more uniform windrow across the field. The long-term solution for operations where merged windrows are routine is to upgrade to a tractor with 10\u201315HP more PTO output to provide genuine reserve above the rated minimum for the baler model.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n <\/p>\n A one-side miss isolates the fault to the individual knotter unit on that side. The shared drive system, PTO speed and twine threading are almost certainly not involved \u2014 if they were, both sides would miss simultaneously.<\/p>\n A both-side simultaneous miss always points to a shared component. The two knotter units do not share mechanical parts \u2014 what they share is: the twine threading path to the spool holders, the PTO drive speed, and the main knotter drive chain.<\/p>\n A single test bale after a fix is not sufficient verification. Any knotter adjustment or part replacement requires a structured verification run before returning to normal production speed \u2014 a fix that holds for one bale may fail on the sixth bale at higher density.<\/p>\n <\/p>\n Most miss-tie causes in Zones 1, 2 and 4 are resolvable by an operator with basic mechanical skills and the operator manual. Zone 3 timing faults and cam wear are more complex and can be made worse by incorrect adjustment attempts. Call technical support when:<\/p>\n <\/p>\n Gearbox torque ratings, PTO shaft specifications and input shaft standards for all 9YF models: \u0915\u0943\u0937\u093f \u0917\u093f\u092f\u0930\u092c\u0949\u0915\u094d\u0938 \u0914\u0930 \u092a\u0940\u091f\u0940\u0913 \u0936\u093e\u092b\u094d\u091f \u0935\u093f\u0928\u093f\u0930\u094d\u0926\u0947\u0936<\/a><\/p>\n<\/div>\n\n\n
\n \nFault Zone<\/th>\n Components<\/th>\n Causes in This Zone<\/th>\n<\/tr>\n<\/thead>\n \n Zone 1 \u2014 Twine Path<\/td>\n Guide eyelets, spool holder, threading route<\/td>\n Causes 1, 2, 3<\/td>\n<\/tr>\n \n Zone 2 \u2014 Knotter Mechanism<\/td>\n Tension discs, bill hook, knife blade, wiper arm<\/td>\n Causes 4, 5, 6, 7<\/td>\n<\/tr>\n \n Zone 3 \u2014 Needle and Cam<\/td>\n Needle arm, cam lobe, cam follower, timing<\/td>\n Causes 8, 9, 10<\/td>\n<\/tr>\n \n Zone 4 \u2014 Power and Crop<\/td>\n PTO speed, tractor load, windrow density<\/td>\n Causes 11, 12<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n Zone 1 \u2014 Twine Path Problems (Causes 1\u20133)<\/h2>\n
Zone 2 \u2014 Knotter Mechanism Problems (Causes 4\u20137)<\/h2>\n
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<\/p>\nZone 3 \u2014 Needle and Cam Timing Problems (Causes 8\u201310)<\/h2>\n
Zone 4 \u2014 Power and Crop Density Problems (Causes 11\u201312)<\/h2>\n
One-Side vs Both-Side Miss: What the Pattern Tells You<\/h2>\n
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<\/p>\nThe After-Fix Verification Protocol<\/h2>\n
When to Stop and Call Technical Support<\/h2>\n
PTO and Driveline Reference for Square Baler Operation<\/h3>\n
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