{"id":1187,"date":"2026-07-29T03:35:39","date_gmt":"2026-07-29T03:35:39","guid":{"rendered":"https:\/\/foragebaler.com\/?p=1187"},"modified":"2026-07-29T03:35:39","modified_gmt":"2026-07-29T03:35:39","slug":"square-baler-twine-breaking-9-causes-and-fixes","status":"publish","type":"post","link":"https:\/\/foragebaler.com\/es\/square-baler-twine-breaking-9-causes-and-fixes\/","title":{"rendered":"Square Baler Twine Breaking: 9 Causes and Fixes"},"content":{"rendered":"
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<\/div>\n
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Troubleshooting Guide \u00b7 All 9YF Models \u00b7 9 Causes Covered<\/p>\n

Square Baler Twine Breaking: 9 Causes and How to Fix Each One<\/h1>\n

Twine breakage is the most disruptive in-field failure a square baler produces \u2014 the bale ejects loose, the pickup continues, and by the time the operator realises what happened several bales worth of crop may be on the ground. Every twine break has a specific root cause. The break location tells you where to look first.<\/p>\n

Covers: break location diagnosis \u00b7 tension discs \u00b7 bill hook geometry \u00b7 spool condition \u00b7 twine quality \u00b7 UV degradation \u00b7 knot strength ratings<\/p>\n

Ver gama de empacadoras cuadradas<\/a>
\nObtenga asistencia t\u00e9cnica<\/a><\/div>\n<\/div>\n<\/div>\n

Step 1: Where Did the Twine Break? Your Starting Diagnostic<\/h2>\n

Before checking any machine component, locate the break point on the failed bale and the free twine end still in the machine. The break location is the most valuable diagnostic indicator available \u2014 it eliminates six of the nine possible causes before you open a single cover.<\/p>\n

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Break AT the Knot<\/div>\n
The knot forms but fails as the bale is ejected and rope tension increases. Causes: tension disc too tight (Cause 3), bill hook geometry pulling wrong (Cause 5), wet twine (Cause 8), or under-rated knot strength (Cause 2).<\/div>\n<\/div>\n
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Break Mid-Bale (Between Knotters)<\/div>\n
The twine parts somewhere along the running length from spool to knotter. Causes: guide eyelet friction (Cause 4), spool tangling (Cause 7), or continuous tension from over-tight discs combined with path friction.<\/div>\n<\/div>\n
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Break at or Near the Spool<\/div>\n
Twine breaks just as it exits the spool holder. Causes: spool core collapse (Cause 7), knotted inner wind pulling through, or a spool holder pin that grips the twine tail incorrectly.<\/div>\n<\/div>\n<\/div>\n

The 9 Causes \u2014 In Diagnostic Priority Order<\/h2>\n

\"9YF-2200S<\/p>\n

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1<\/div>\n
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Twine Knot Strength Rating Too Low for Bale Density<\/div>\n
Break location: AT the knot \u00b7 Pattern: consistent, same side or both sides<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

Every polypropylene twine spool is rated by knot strength in kilograms. The knot strength rating must exceed the combined rope load applied at the tightest point of the bale ejection cycle. A bale weighing 30kg is held by two ropes, each carrying approximately 15kg static load \u2014 but the dynamic load during ejection can reach 2\u20133 times this value as the bale is pushed through the chute. A twine rated at 80kg knot strength may consistently fail under a 30kg high-density alfalfa bale.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Match twine knot strength to your maximum bale weight using this rule of thumb: minimum knot strength = 4 times the target bale weight. For 24kg bales, use at minimum 96kg-rated twine. For 35kg high-density bales, use 140kg or above. If you cannot determine the rating from the spool label, contact your supplier \u2014 unlabelled or illegibly labelled twine is a risk regardless of other machine settings.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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2<\/div>\n
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Tension Discs Set Too Tight<\/div>\n
Break location: AT the knot or mid-bale \u00b7 Pattern: consistent, worsens at higher density settings<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

The tension disc mechanism maintains constant back-pressure on the twine as it feeds from the spool toward the knotter. When set too tight, this back-pressure places the twine under continuous tension throughout the entire bale cycle. When the knot then tightens under bale compression load, the combined disc tension plus ejection load exceeds the knot strength rating. This is the single most common cause of knot-point breakage after a twine change or density-setting increase.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Back off the tension disc adjustment nut by one half-turn. Run 5 test bales at your standard density setting. If the break stops, the disc was over-tightened. Note: if reducing disc tension causes the loop to become slack and misshapen \u2014 producing a missed knot \u2014 the issue is a combined disc-plus-bill-hook problem. Both sides must be adjusted equally; unequal disc tension produces one reliable knot and one consistently weaker knot per bale cycle.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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3<\/div>\n
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Worn or Grooved Twine Guide Eyelets Creating Friction<\/div>\n
Break location: mid-bale along the running path \u00b7 Pattern: frayed break face, not a clean cut<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

Guide eyelets in the twine routing path develop wear grooves from seasons of twine running through them at speed. A grooved eyelet acts as a saw \u2014 each bale cycle abrades the twine surface at that point. The twine weakens progressively until it fails mid-pull. The break typically has a frayed, fibrous appearance rather than the clean parting that tension failure produces. This cause is very frequently overlooked because the eyelet looks undamaged from a distance.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Thread a cloth along the full twine path from spool to needle eye \u2014 any snag indicates a rough point that will break twine. Alternatively, run a bare finger around the inside face of each guide eyelet; a groove is clearly felt even when not visible. Smooth minor burrs with fine emery cloth. Replace any eyelet with a groove deeper than 0.5mm \u2014 replacement cost is negligible compared to the labour of recovering loose bales from the field.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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4<\/div>\n
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Incorrect Twine Threading Route<\/div>\n
Break location: consistent after a spool change \u00b7 Pattern: always the same side, from the first bale<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

A twine routed through the wrong guide eyelet or missing one eyelet in the sequence changes the angle of the twine under tension. At certain incorrect angles, the twine bears against a metal edge rather than running through the centre of a guide \u2014 this creates a stress concentration that causes the twine to fail at that edge point on the first or second bale after a spool change.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Pull all twine from both sides and re-thread using the operator manual diagram \u2014 not from memory. Every operator manual has a threading diagram for a reason: the path is non-intuitive and one wrong guide is enough to cause consistent breakage. After re-threading, pull the twine from needle to spool by hand with the machine stopped \u2014 the pull should be smooth and consistent with no tight spots or angle changes that could indicate incorrect routing.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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5<\/div>\n
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Bill Hook Geometry Causing Knot Pull-Through<\/div>\n
Break location: AT the knot \u00b7 Pattern: knot forms visibly but fails during ejection<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

A worn or chipped bill hook tip changes the geometry of how the knot loop is formed and seated. When the knot geometry is slightly wrong \u2014 the loop closing around the rope at an incorrect angle \u2014 the knot tightens in a way that concentrates tensile force at one strand rather than distributing it across the full knot cross-section. This produces a knot that appears correctly formed but fails at significantly lower loads than a correctly formed knot from the same twine.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Examine the bill hook tip face \u2014 run a fingernail across the curved surface. Any flat spot, rounding or chip is reason for replacement. Replace both bills as a matched pair: a new bill against a worn bill produces knots of different geometry on each cycle, making the problem intermittent and harder to diagnose. After replacement, run 10 test bales and pull on each knot firmly \u2014 a correctly formed knot tightens under tension without slipping.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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6<\/div>\n
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UV Degradation \u2014 Old or Incorrectly Stored Twine<\/div>\n
Break location: AT the knot or mid-bale \u00b7 Pattern: breakage rate increases through the day as temperature rises<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

Polypropylene twine undergoes photochemical degradation when exposed to ultraviolet radiation. Spools left on the baler outdoors between seasons, stored in a sunny barn, or left in the field during a session absorb UV that breaks polymer chains in the fibre. The tensile strength reduction from one summer of outdoor UV exposure can exceed 30%. Degraded twine is visibly brittle and discoloured but the strength reduction begins well before visible signs appear.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Always store twine spools in a closed, UV-opaque container or in a shaded building. Remove spools from the baler at the end of each season and store indoors. Do not bale with spools that were left on an outdoor machine for more than one week of direct sun exposure. When testing old stock, pull a metre of twine and attempt to break it by hand \u2014 fresh twine of the correct rating should be very difficult to break by pulling; twine that breaks with moderate hand tension is degraded and should be replaced.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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7<\/div>\n
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Spool Core Collapse \u2014 Irregular Feed Rate<\/div>\n
Break location: near the spool or mid-bale \u00b7 Pattern: intermittent, worsens as spool empties toward the core<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

The cardboard or plastic core that the twine is wound onto can soften and collapse when stored in damp conditions. As the spool empties toward the core, the collapsed core compresses under the remaining twine weight and produces an irregular shape \u2014 the twine binds and then releases in jerks as it unwinds over the deformed core surface. Each jerk creates a brief tension spike in the twine that can exceed the knot strength rating and cause a break at the point of highest stress concentration.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Remove the spool and check the core by compressing it between fingers \u2014 a good core is firm and resists deformation. A core that compresses easily or has visible deformation should be discarded rather than continued with. Store twine in a dry location off the ground and away from roof condensation. Never stand spools upright on a damp concrete floor \u2014 water wicks up through the paper core from the base contact point.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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8<\/div>\n
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Wet Twine \u2014 Moisture Reduction in Knot Strength<\/div>\n
Break location: AT the knot \u00b7 Pattern: breakage rate higher on humid days or after morning dew<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

Polypropylene twine absorbs atmospheric moisture and this absorption reduces tensile strength at the knot by 15\u201325% in high-humidity conditions. Sisal twine \u2014 where still used \u2014 is more severely affected by moisture. When baling on humid mornings, baling into wet windrows or when the spool was exposed to rain, the effective knot strength available is substantially below the rated value on the label. This is why twine that tied reliably in dry afternoon conditions fails consistently on humid mornings from the same spool.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Allow wet spools to dry completely in a warm, sheltered location before baling \u2014 this takes 12\u201324 hours for a fully saturated spool. If you must bale in humid conditions with borderline-rated twine, upgrade to a higher knot strength rating that provides sufficient margin even at a 20% wet-condition reduction. Cover the spool holder on the machine during overnight sessions to prevent dew absorption. On humid baling days, upgrade twine strength by one grade above your normal dry-weather choice.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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9<\/div>\n
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Diameter Inconsistency in Economy-Grade Twine<\/div>\n
Break location: variable \u00b7 Pattern: intermittent, no clear location pattern, switches sides<\/div>\n<\/div>\n<\/div>\n
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Causa principal<\/div>\n

Economy-grade twine produced without tight quality control exhibits significant diameter variation within a single spool \u2014 sections of higher diameter create increased tension disc resistance during those passes, while thinner sections produce lower tension that allows a slack loop. The thicker sections can temporarily spike the running tension above the knot strength rating, while the thinner sections produce missed knots or poorly formed loops. The result is a random pattern of breaks and misses that is almost impossible to diagnose without first testing a different twine brand on the same machine.<\/p>\n<\/div>\n

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Fix Procedure<\/div>\n

Replace the suspect twine with a named-brand product from an established manufacturer. If the twine breaks stop immediately on the new brand, the old twine was the cause \u2014 diameter inconsistency is confirmed. Going forward, purchase twine only from suppliers who can provide the rated knot strength, metres per kg and diameter specification in writing. The cost difference between quality and economy twine per bale is less than $0.05 \u2014 the labour and crop cost of a single field breakdown from failed twine far exceeds the seasonal saving from economy purchasing.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

\"small<\/p>\n

Twine Knot Strength Reference Chart<\/h2>\n

\"9YF<\/p>\n

\n\n\n\n\n\n\n\n\n
Application \/ Bale Weight<\/th>\nMin Knot Strength<\/th>\nGrado recomendado<\/th>\nNotas<\/th>\n<\/tr>\n<\/thead>\n
Lightweight hay \/ straw \u2014 up to 18kg<\/td>\n80 kg<\/td>\nStandard polyprop<\/td>\n9YF-1700 typical range. Minimum acceptable grade.<\/td>\n<\/tr>\n
Standard hay \u2014 18\u201326kg<\/td>\n110 kg<\/td>\nMedium polyprop<\/td>\nMost common 9YF-1900 and 9YF-2200 use case.<\/td>\n<\/tr>\n
High-density hay \u2014 26\u201336kg<\/td>\n140kg<\/td>\nHeavy-duty polyprop<\/td>\n9YF-2200S at high density. Do not substitute lower grade.<\/td>\n<\/tr>\n
Maximum density \/ shredder models \u2014 30\u201340kg<\/td>\n160 kg o m\u00e1s<\/td>\nPremium baler twine<\/td>\n9YFS-2.2 at maximum density. Confirm rated strength before purchasing.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\"square<\/p>\n

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PTO Drive and Gearbox Reference for Twine Tension<\/h3>\n
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\n\"agricultural
\n<\/a><\/p>\n

PTO shaft and gearbox specifications for all 9YF baler power classes: Especificaciones de la caja de engranajes agr\u00edcola y del eje de la toma de fuerza (PTO).<\/a><\/p>\n<\/div>\n

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Inconsistent PTO speed causes twine tension fluctuation that compounds disc and path friction issues \u2014 a slipping driveshaft CV joint or worn slip clutch produces load spikes that exceed rated knot strength even when the disc setting is correct. Full driveshaft specifications: Gu\u00eda de dimensionamiento del eje de transmisi\u00f3n de la toma de fuerza y \u200b\u200bde la junta homocin\u00e9tica<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

Frequently Asked Questions \u2014 Square Baler Twine Breaking<\/h2>\n
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\nMy twine was working fine and now breaks on every third or fourth bale. What changed?+<\/span><\/summary>\n
An intermittent break pattern that develops mid-session \u2014 rather than from the start \u2014 typically points to one of three progressive failures. First: a guide eyelet is developing a wear groove that worsens through the session as the twine abrades it further. Second: the spool is nearing the core where winding irregularities occur. Third: a bill hook is at the edge of its wear limit and the knot geometry degrades as the hook face wears further through the session. Check the guide eyelets first \u2014 run a finger along each one. Then inspect how much twine remains on the spool; if within the last 25%, fit a new spool. If both check out, inspect the bill hooks for tip wear.<\/div>\n<\/details>\n
\nShould I use sisal or polypropylene twine in my 9YF baler?+<\/span><\/summary>\n
Polypropylene is the current industry standard for the 9YF series and for small square baler use generally. Polypropylene offers higher tensile strength per unit weight than sisal, is UV-stabilised in quality grades, does not absorb moisture to the same degree, and is available in a wider range of knot strength ratings. Sisal is biodegradable \u2014 a significant advantage for organic farming or markets where plastic contamination in animal feed is a concern \u2014 but requires more careful moisture management and degrades in outdoor storage faster than polypropylene. For most commercial applications with the 9YF series, polypropylene in the correct strength grade is the recommended choice. Confirm with your end buyer whether sisal is required or preferred before switching \u2014 some export markets and organic certification schemes specify natural fibre twine.<\/div>\n<\/details>\n
\nCan I continue baling when one side keeps breaking twine?+<\/span><\/summary>\n
Continuing with one side breaking is not recommended. A bale with only one rope tie is significantly weaker and more likely to burst during handling, stacking and transport. If you must continue \u2014 to complete a cutting before weather changes \u2014 reduce bale density to the minimum setting to reduce the load on the functioning rope, collect all single-tied bales in a separate section of the barn, and re-tie or hand-bind them before stacking more than two layers high. Fix the failing side before the next baling session. One-sided twine breaking in almost all cases involves a component on that specific side \u2014 check the tension disc, guide eyelets and bill hook on the affected knotter first.<\/div>\n<\/details>\n
\nHow do I know what knot strength rating my current twine is?+<\/span><\/summary>\n
The knot strength rating should appear on the spool label, typically expressed in kilograms (kg) or pounds (lb) \u2014 check both the main product label and any secondary stickers. If the label has been removed or is illegible, contact the supplier with the product name or SKU for the specification sheet. As a field test, a simple knot test gives a rough estimate: tie a simple overhand knot in a short length of the twine, hold the free ends and pull with force. Professional-grade 110kg twine should require substantial effort to break with one hand. If twine breaks easily by hand or with one firm pull, it is either low-grade, degraded, or wet \u2014 do not use it for high-density baling. For precision, the correct test is a certified tensile tester, but the hand test provides a useful quality check in the field.<\/div>\n<\/details>\n
\nThe twine breaks but the knot looks perfectly formed on the bale. What does this mean?+<\/span><\/summary>\n
A correctly formed knot that fails under load points specifically to a strength problem rather than a mechanism problem. The two most likely causes when the knot geometry is correct: twine knot strength rating is insufficient for the bale weight and density (the knot forms correctly but cannot sustain the ejection load), or the tension disc is set too tight and adds load to the knot at the moment of maximum compression. In both cases the knotter mechanism itself is operating correctly. Start by upgrading twine to the next strength grade and run 20 test bales. If breakage continues with the stronger twine, back off the tension disc by half a turn and retest. This two-step diagnostic will identify whether it is a twine strength issue, a disc setting issue, or a combination of both.<\/div>\n<\/details>\n
\nHow many metres of twine does a small square baler use per bale?+<\/span><\/summary>\n
The twine consumption per bale depends on the bale cross-section circumference and the two rope path lengths. For the 9YF series 460\u00d7360mm bale format, the perimeter (the length of rope around the bale cross-section) is approximately 1,640mm \u2014 plus the needle travel distance and the length inside the chamber. Total twine per bale per rope is approximately 2.2\u20132.8 metres depending on machine geometry. With two ropes per bale, total twine consumption is approximately 4.4\u20135.6 metres per bale. For a 5,000-bale season at 5 metres per bale, total twine consumption is approximately 25,000 metres or 25km. A standard 6,500-metre spool produces approximately 1,160\u20131,480 bales. Plan to carry at least 5 spools per side for a full-day session to avoid field changes at inconvenient times.<\/div>\n<\/details>\n
\nIs there a way to prevent twine from tangling on the spool during baling?+<\/span><\/summary>\n
Spool tangling \u2014 where loose winds fall over each other and create a knot at the spool holder \u2014 usually has one of three causes. First: the spool is mounted with incorrect orientation \u2014 most balers require the twine to unwind from the top of the spool rotating away from the machine; unwinding from the bottom causes loops to form. Check the operator manual for the correct spool direction. Second: the spool holder tension is too loose, allowing the spool to spin freely and overrun \u2014 the twine accumulates slack that eventually tangles. Add a mild friction device (a rubber washer or light spring washer) to create slight spool braking. Third: the spool was previously tangled at its inner wind from irregular winding at the manufacturing stage \u2014 these spools will eventually tangle regardless of machine settings. Inspect the inner few winds of a new spool when loading it; any crossed or loose winds near the core indicate a manufacturing defect. Return and replace such spools before they cause a field breakdown.<\/div>\n<\/details>\n
\nAfter fixing twine breaks, how many bales should I run before returning to normal production?+<\/span><\/summary>\n
Run a minimum of 20 verification bales at your normal forward speed and normal density setting before concluding that the fix is complete. Check the rope ends on every bale in the verification run \u2014 a clean, consistent cut face with a firm knot that tightens under tension indicates correct operation. A ragged rope end indicates knife dullness. A loop that slides when pulled indicates a disc or bill hook problem still present. A rope that breaks during the verification run indicates the root cause has not been fully resolved. Do not reduce bale density for the verification run \u2014 testing at reduced density may give a false positive, since a twine strength problem only manifests at the density and bale weight that creates the overload condition. If the verification run of 20 bales is clean, advance to full production.<\/div>\n<\/details>\n<\/div>\n

Find the Right Baler and Twine Setup for Your Operation<\/h2>\n
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El 9YF series square balers<\/a> are matched to specific twine strength grades by model and density setting. Contact us with your bale weight target and crop type and we will confirm the correct twine specification alongside the machine recommendation.<\/p>\n

Ver gama de empacadoras cuadradas<\/a>
\nObtenga asistencia t\u00e9cnica<\/a><\/div>\n

\n<\/div>\n

Editor: Cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Troubleshooting Guide \u00b7 All 9YF Models \u00b7 9 Causes Covered Square Baler Twine Breaking: 9 Causes and How to Fix Each One Twine breakage is the most disruptive in-field failure a square baler produces \u2014 the bale ejects loose, the pickup continues, and by the time the operator realises what happened several bales worth of […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[28],"tags":[],"class_list":["post-1187","post","type-post","status-publish","format-standard","hentry","category-forage-baler"],"_links":{"self":[{"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/posts\/1187","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/comments?post=1187"}],"version-history":[{"count":2,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/posts\/1187\/revisions"}],"predecessor-version":[{"id":1190,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/posts\/1187\/revisions\/1190"}],"wp:attachment":[{"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/media?parent=1187"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/categories?post=1187"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/foragebaler.com\/es\/wp-json\/wp\/v2\/tags?post=1187"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}