8 Supplies for Fixing Old Baler Knotters

A field of crisp, dry hay ready for the barn quickly turns into a nightmare when an old square baler starts spitting untied bales across the meadow. Vintage knotters look intimidating with their intricate dance of billhooks, twine discs, and wipers, but most mistying issues come down to simple wear, dirt, and misadjustment. Equipping the workshop with the right diagnostic and maintenance supplies transforms these temperamental mechanical assemblies from head-scratching liabilities into reliable workhorses.

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Understanding Common Vintage Baler Knotter Issues

Most vintage square balers rely on mechanical precision measured in fractions of an inch. A tying misfire is rarely caused by a ruined knotter assembly; it is almost always caused by surface rust on a billhook, a dull twine knife, or improper tension on the twine holder. Understanding how these mechanical components interact helps pinpoint the failure before randomly turning adjustment bolts.

Twine hanging from the billhook typically indicates a dull knife or insufficient wiper travel failing to strip the finished knot cleanly. Conversely, loops that slip out before the bale finishes compacting point directly to low twine disc tension or worn gripping notches. Diagnosing the exact knot pattern left in the field prevents wasting time replacing parts that merely need cleaning and a quarter-turn adjustment.

Safety Preparations Before Servicing Your Baler

Working on a baler requires absolute discipline because kinetic energy stored in the plunger and flywheel can cause catastrophic injury. Always disengage the tractor PTO, shut off the engine, remove the ignition key, and disconnect the PTO driveline entirely before opening the knotter deck.

Trip the knotter clutch manually and rotate the mechanism entirely by hand using the flywheel to reach the desired service position. Never rely on hydraulic friction or gravity to hold the needle frame upright. Always insert the mechanical needle safety latch or secure a timber block in front of the plunger before reaching into the knotter bay.

Feeler Gauge – Starrett 66T Thickness Gage Set

Clearances between the billhook tongue, the stripper arm, and the twine disc drive gear require exact tolerances to tie reliably. Eyeballing these micro-gaps leads to skipped knots or chewed-up twine, making a precise steel feeler gauge mandatory for setup.

The Starrett 66T Thickness Gage Set provides the exact measurement range needed (.0015" to .025") with tempered steel blades that slide smoothly into tight mechanical clearances without bending permanently. Unlike cheaper imported gauges that corrode after a damp morning in the tractor cab, Starrett’s rust-resistant steel and clearly etched markings hold up to gritty farm shop conditions.

• Hardened steel blades resist warping and provide precise tactile feedback
• Locking nut mechanism keeps the selected leaf firmly positioned during measurements
• Extended blade reach accesses tight clearances between knotter frame castings

This tool is essential for any operator tuning billhook opening gaps and wiper arm clearances on vintage New Holland, John Deere, or Massey Ferguson knotters. It is unnecessary for farmers who outsource all mechanical repairs, but indispensable for DIY field tuning.

Hanging Spring Scale – Berkley Mechanical Scale

Knotter performance hinges entirely on twine tension at both the twine disc holder and the billhook tongue. Guessing tension by pulling with bare hands inevitably leads to snapped twine during heavy windrows or loose bales that fall apart during transport.

The Berkley Mechanical Scale offers a dependable, battery-free way to measure pull tension in the critical 0 to 50-pound range. Its robust mechanical spring movement handles outdoor dust, field drops, and storage in an unheated barn without losing calibration or suffering dead electronic displays.

• Direct mechanical spring readout functions reliably in hot sun and cold spring mornings
• Sturdy steel hook attaches easily to knotted twine test loops
• Compact profile fits neatly in standard on-board baler toolboxes

Pull testing requires tying a loop of standard baler twine through the twine disc, pulling straight along the normal twine path, and noting the exact resistance before the twine slips. This scale is perfect for operators switching between sisal and plastic twine, which require completely different tension settings.

Baler Knife – John Deere Replacement Twine Blade

As the knot completes its loop, the stripper arm sweeps forward, forcing the strands against a small stationary or arm-mounted blade to sever them cleanly. A dull or nicked blade leaves frayed twine ends that snag on the billhook, resulting in trailing strings and broken bales.

The John Deere Replacement Twine Blade utilizes hardened high-carbon tool steel designed to slice tough sisal and abrasive polypropylene twine without rolling its cutting edge. Universal aftermarket blades often dull rapidly or arrive with improper bevel angles that tear fibers instead of slicing cleanly.

• Precision-ground cutting edge provides clean, instant cuts with minimal mechanical resistance
• Heat-treated carbon steel construction resists premature wear from abrasive modern plastic twine
• Direct factory bolt pattern prevents sloppy fitment and blade chatter during cycling

Check the clearance between the knife blade and the stripper shoe during a slow dry cycle to prevent metal-on-metal collision. This wear item is essential for anyone experiencing ragged twine tails or knots hanging on the billhook, though operators with completely specialized knife-arm assemblies must verify exact mounting hole spacing.

Penetrating Oil – Kano Kroil Original Penetrant

Vintage balers often sit in unheated sheds or open lean-tos through damp winters, causing knotter frame pivot pins and adjustment springs to freeze solid. Forcing a rusted tension adjustment bolt will easily strip vintage, hard-to-source cast-iron threads.

Kano Kroil Original Penetrant features an ultra-low surface tension formulation engineered to creep into microscopic openings down to one-millionth of an inch. While standard multi-purpose spray oils merely pool on the surface, Kroil actively breaks down stubborn rust and dried plant sap inside threaded collars and pivot shafts.

• Microscopic creeping action penetrates deeply into frozen tensioner threads and hinge pins
• Fast-acting chemical solvency dissolves dried grease, rust, and crop residue
• Pinpoint applicator nozzle directs fluid precisely where needed without saturating friction parts

Apply Kroil generously to billhook pivots, disc pinions, and adjustor springs 24 hours prior to mechanical teardown. Wipe away excess fluid before entering the field to prevent fine hay chaff from sticking to knotter components. This penetrant is invaluable when resurrecting classic machinery, though less necessary on machines that are routinely greased and sheltered.

Pin Punch Set – Mayhew Steel Products Roll Punch

Knotter assemblies rely heavily on roll pins and shear pins to lock gears, pinions, and knotter arms onto drive shafts. Driving out a sheared or rusted pin with an ordinary flat punch or makeshift nail will mushroom the pin ends, locking the component onto the shaft permanently.

The Mayhew Steel Products Roll Pin Punch Set features a specialized ball-tip centering design that seats directly inside the hollow pin core, preventing wall collapse and slippage. Made from heat-treated alloy steel, these punches resist bending even when striking stuck tension pins on a hardened knotter driveshaft.

• Patented spherical ball tip centers punch securely inside roll and spring pins
• Tempered alloy steel body transfers maximum striking energy without flexing
• Comprehensive size assortment covers all common small-baler pinion and link pin diameters

Match the punch diameter precisely to the roll pin to avoid gouging adjacent cast-iron housings. Use short, decisive hammer blows rather than excessive force to walk stuck pins free. This set is a vital purchase for anyone replacing billhook pinions, drive gears, or needle links on classic square balers.

Emery Cloth – 3M Utility Cloth Sheet Roll 241D

Billhooks and twine discs must maintain glass-smooth, polished surfaces so twine loops slide off cleanly the instant the wiper arm advances. Surface rust, micro-burrs, and rough casting edges catch natural twine fibers, holding the knot hostage and snapping strings under bale pressure.

The 3M Utility Cloth Sheet Roll 241D provides an aluminum oxide abrasive bonded to a flexible cloth backing that conforms easily around rounded billhook horns without tearing. Standard wood sandpaper disintegrates when wrapped around tight metal contours, but this cloth-backed abrasive withstands vigorous hand buffing.

• Flexible J-weight cloth backing wraps smoothly around tight billhook curves and disc channels
• High-grade aluminum oxide abrasive quickly removes rust without gouging base metal
• Convenient roll format lets the operator tear off custom narrow strips for tight spaces

Tear narrow strips to wrap around billhook tongues, buffing in the direction of twine travel to avoid creating cross-hatch micro-grooves. Never use aggressive power grinders or coarse files on knotter billhooks, as hand polishing preserves critical factory profiles. This material is indispensable for pre-season prep on any machine showing light surface oxidation.

Wire Brush – Lincoln Electric Carbon Scratch Brush

Baling generates massive amounts of airborne dust, stem fragments, and plant sap that cake into gear teeth and twine disc slots. This debris packs tightly into the disc notches, preventing twine from seating at the proper depth and causing repeated missed knots.

The Lincoln Electric Carbon Scratch Brush features dense, tempered carbon steel bristles embedded in a durable wooden handle that withstands aggressive scrubbing in greasy, tight spaces. Its narrow profile slips neatly between knotter frames and twine disc assemblies where bulky shop brushes cannot fit.

• High-tensile carbon steel bristles aggressively scour away baked-on grease and chaff
• Narrow brush profile reaches into recessed twine disc slots and pinion gear teeth
• Solid hardwood handle provides a secure, non-slip grip when reaching into knotter bays

Use this brush daily before greasing and immediately at the end of each field run to keep moving parts clean. Stiff carbon wire removes packed debris without shedding loose bristles into the gear mesh. It is a necessary daily tool for any baler operator, as softer brass or nylon brushes lack the rigidity required to clear compacted chaff.

EP2 Grease – Lucas Oil Heavy Duty Red N Tacky

Knotters experience high cyclical friction loads and exposure to abrasive dust that quickly grinds dry metal pivots down. Using an inferior lubricant that washes out or melts under high ambient temperatures leaves knotter components unprotected during long, hot summer workdays.

Lucas Oil Heavy Duty Red N Tacky is an extreme-pressure (EP2) lithium-complex grease fortified with rust and oxidation inhibitors that stays in place under heavy vibration. Its tacky formulation resists slinging off fast-moving pinion gears while sealing pivot bushings against airborne hay grit.

• High-tack lithium complex formula clings to exposed gears and high-friction pivots
• Extreme Pressure (EP) additive package protects against mechanical wear under shock loads
• Excellent water and heat resistance prevents breakdown during humid storage and hot field runs

Grease zerk fittings sparingly—usually one or two pumps is sufficient, as excessive grease attracts dirt and creates an abrasive grinding paste. This grease is ideal for complete driveline, needle drive, and knotter maintenance across all brands of square balers. Skip thin, non-tacky chassis greases that run when knotter decks heat up in the sun.

How to Test and Adjust Knotter Tension Properly

Adjusting knotters should always follow a logical, step-by-step sequence rather than trial-and-error bolt turning. Begin by anchoring the mechanical spring scale to the twine end emerging from the twine disc, pulling directly toward the needles in line with the natural twine route. Adjust the leaf spring nut in quarter-turn increments until the pull matches the baler manual’s exact specification, typically 35 to 40 pounds for standard sisal.

Tension Check Order: 1. Twine Disc Holder --> Adjust leaf spring nut to factory pull weight 2. Billhook Tongue --> Adjust tension spring nut for clean knot release 3. Wiper Arm Sweep --> Check stripper shoe clearance against billhook

Next, test billhook tongue tension by pulling a completed test knot off the billhook with the scale attached. The tongue should open smoothly under moderate, consistent pull—typically 10 to 15 pounds. If it is too loose, the knot unties inside the chamber; if too tight, the twine snaps or bends the billhook shaft.

Always cycle the baler manually through two full tying sequences by turning the flywheel by hand after making adjustments. Visually confirm that the needles clear the knotter frame cleanly, the discs rotate smoothly to receive the next strand, and the knives part the twine without tearing.

Preventive Maintenance Tips for Trouble-Free Baling

Reliability during the heat of haying season begins with methodical cleaning habits at the end of every working day. Blow all chaff and crop residue off the knotter deck using compressed air or a leaf blower after every single use, preventing moisture-trapping debris from rusting polished contact points overnight.

Apply a light protective film of clean oil or rust preventative to the billhook and twine discs whenever rain delays baling for more than two days. Polished steel surfaces lose their mirror finish quickly in humid barn air, and a brief polish with emery cloth before the next outing will prevent frustrating first-bale jams.

Store the baler with the needle frame parked fully home in the retracted position and the knotter safety latch engaged. Inspect all roll pins, shear bolts, and drive chain tensions before heading to the field, ensuring smooth, uninterrupted power delivery to the knotter mechanism when hay is down and weather windows are short.

Keeping an old square baler running reliably does not require magic, only clean mechanical surfaces, correct clearances, and precisely calibrated tensions. With this core set of diagnostic and maintenance supplies on hand, tuning vintage knotters becomes a straightforward routine that keeps the field moving and every bale securely tied.