{"id":1149,"date":"2026-05-19T08:10:30","date_gmt":"2026-05-19T08:10:30","guid":{"rendered":"https:\/\/pto-gearbox.net\/?p=1149"},"modified":"2026-05-19T08:11:22","modified_gmt":"2026-05-19T08:11:22","slug":"pto-gearbox-for-rotary-cutters","status":"publish","type":"post","link":"https:\/\/pto-gearbox.net\/es\/pto-gearbox-for-rotary-cutters\/","title":{"rendered":"Caja de engranajes de toma de fuerza para cortadoras rotativas: Gu\u00eda completa"},"content":{"rendered":"
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Caja de engranajes de toma de fuerza para cortadoras rotativas: Gu\u00eda completa<\/h1>\n

Over 73% of rotary cutter downtime traces back to gearbox-related failures. This guide covers every factor that determines whether your gearbox lasts one season or ten.<\/p>\n

Get a Custom Quote in 24 Hours<\/a><\/p>\n<\/div>\n<\/div>\n

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<\/p>\n

What a Rotary Cutter Gearbox Actually Does<\/h2>\n

A caja de engranajes para cortadoras rotativas<\/a> sits between your tractor’s PTO shaft and the cutting blades. Its primary job is straightforward: take the rotational speed from your tractor \u2014 typically 540 RPM \u2014 and convert it to the blade speed and torque your cutter needs. That conversion involves direction change, speed reduction, and torque multiplication all happening inside a single compact housing.<\/p>\n

Most designs use a right-angle configuration with spiral bevel gears. The tractor PTO spins a horizontal input shaft, and the gearbox redirects that power 90 degrees downward to the vertical blade spindle. This arrangement keeps the tractor PTO connection at a comfortable working height while driving the blades at ground level.<\/p>\n

\"Rotary<\/p>\n

Without the correct PTO gearbox, your rotary cutter either spins too fast and throws debris dangerously, or too slow and stalls in thick brush. The gearbox is not merely a connector \u2014 it is the engineering heart of the implement.<\/p>\n

Gear Ratio Selection: Matching Speed to Cutting Load<\/h2>\n

Gear ratio is the single most important specification when selecting a rotary cutter gearbox. It determines blade tip speed, cutting force, and how much tractor horsepower actually reaches the blades. Choosing the wrong ratio leads to premature gear wear, excessive fuel consumption, and inconsistent cut quality.<\/p>\n

\n\n\n\n\n\n\n\n\n
Relaci\u00f3n de transmisi\u00f3n<\/th>\nRPM de salida<\/th>\nEsfuerzo de torsi\u00f3n<\/th>\nMejor aplicaci\u00f3n<\/th>\n<\/tr>\n<\/thead>\n
1 : 1<\/td>\n540<\/td>\n1.0\u00d7<\/td>\nLight grass, pasture maintenance<\/td>\n<\/tr>\n
1 : 1.47<\/td>\n367<\/td>\n1.47\u00d7<\/td>\nMedium brush, field clearing<\/td>\n<\/tr>\n
1 : 1.92<\/td>\n281<\/td>\n1.92\u00d7<\/td>\nHeavy brush, saplings up to 3 in.<\/td>\n<\/tr>\n
1 : 2.4<\/td>\n225<\/td>\n2.4\u00d7<\/td>\nHeavy-duty land clearing, hardwood<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

A 1:1.47 ratio is the most widely used across general farm applications. It provides enough torque multiplication for moderate brush while maintaining blade tip speed above the minimum threshold for a clean cut. If your operation regularly encounters hardwood saplings, step up to a 1:1.92 or higher ratio and pair it with a tractor PTO gearbox rated above 60 HP.<\/p>\n

<\/p>\n

Torque and Horsepower: How Much Power Your Gearbox Needs<\/h2>\n

Tractor horsepower tells you what the engine produces. PTO horsepower tells you what actually reaches the gearbox \u2014 and those two numbers are never the same. Drivetrain losses between the engine and PTO stub typically consume 15% to 20% of rated engine power. A 75 HP tractor delivers roughly 60 to 64 HP at the PTO output.<\/p>\n

Your caja de cambios agr\u00edcola<\/strong> must be rated to handle at least 125% of the maximum PTO horsepower your tractor can deliver. That safety margin accounts for impact loads when the blades strike rocks, fence posts, or hidden stumps.<\/p>\n

<\/p>\n

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\u2699\ufe0f Output Torque Calculation<\/p>\n

Torque (ft-lb) = (HP \u00d7 5,252) \u00f7 RPM. For a 60 PTO HP tractor feeding a 1:1.47 ratio gearbox, the output torque is approximately (60 \u00d7 5,252) \u00f7 367 = 859 ft-lb<\/strong>. That figure determines your bearing selection, shaft diameter, and housing wall thickness requirements.<\/p>\n<\/div>\n

\"Aplicaci\u00f3n<\/div>\n

<\/p>\n

Inside the Gearbox: Component Breakdown<\/h2>\n

Understanding what sits inside your rotary cutter gearbox helps you diagnose problems before they become catastrophic. Every component serves a specific function in the power transmission chain.<\/p>\n

\"Caja<\/p>\n

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\ud83d\udd29<\/p>\n

Input Shaft & Spline<\/p>\n

Receives power through a splined coupling \u2014 6-spline (1-3\/8 in.) for 540 RPM or 20-spline (1-3\/4 in.) for 1000 RPM. Over time, spline wear creates backlash that amplifies shock loads and accelerates gear damage.<\/p>\n<\/div>\n

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\u2699\ufe0f<\/p>\n

Spiral Bevel Gear Set<\/p>\n

The core of every right-angle gearbox. Spiral bevels engage gradually \u2014 multiple teeth share load simultaneously, reducing noise, vibration, and peak tooth stress by 30\u201340% compared to straight bevel gears.<\/p>\n<\/div>\n

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\ud83d\udd27<\/p>\n

Output Shaft & Blade Flange<\/p>\n

Extends downward to the blade mount. Shafts machined from 4140 or 4340 chromoly steel with induction-hardened bearing journals outlast plain carbon steel alternatives significantly. The bolt pattern (4- or 6-bolt) must match the cutter deck.<\/p>\n<\/div>\n

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\ud83d\udee1\ufe0f<\/p>\n

Bearings, Seals & Lubrication<\/p>\n

Tapered roller bearings in opposing pairs manage radial and thrust loads. Lip seals keep contaminants out. A breather vent equalizes internal pressure \u2014 a blocked breather forces oil past seals, often misdiagnosed as seal failure.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Five Common Failure Modes and How to Prevent Them<\/h2>\n

Knowing why gearboxes fail is more valuable than knowing how they work. Here are the five most frequent failure modes, ranked by occurrence:<\/p>\n

<\/p>\n

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1<\/span><\/p>\n

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Gear Tooth Pitting & Spalling<\/p>\n

Caused by insufficient lubrication, contaminated oil, or sustained overload. Micro-pits grow into spalls that generate metal particles and cascade into bearing damage. Prevention:<\/strong> Change gear oil every 100 operating hours; use EP-rated 80W-90.<\/p>\n<\/div>\n<\/div>\n

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2<\/span><\/p>\n

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Input Shaft Spline Wear<\/p>\n

Loose driveline connections allow the shaft to hammer against spline teeth, wallowing out the profile. Prevention:<\/strong> Check driveline slip joint condition seasonally; replace worn universal joints promptly.<\/p>\n<\/div>\n<\/div>\n

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3<\/span><\/p>\n

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Seal Failure & Oil Loss<\/p>\n

Often triggered by a blocked breather vent rather than actual seal degradation. Internal pressure forces oil past the lip seals. Prevention:<\/strong> Clean or replace the breather vent at every oil change.<\/p>\n<\/div>\n<\/div>\n

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4<\/span><\/p>\n

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Bearing Seizure<\/p>\n

Running with low or contaminated oil for extended periods breaks down the bearing cage, circulating metal fragments through the entire gearbox. Prevention:<\/strong> Check oil level before every use; inspect for water contamination (milky oil) after wet conditions.<\/p>\n<\/div>\n<\/div>\n

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5<\/span><\/p>\n

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Housing Fracture<\/p>\n

Severe impact when blades strike immovable objects. Cast iron housings crack; ductile iron or cast steel absorbs shock better. Prevention:<\/strong> Walk new fields before mowing; use a gearbox with a shear bolt or slip clutch for rocky terrain.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

<\/p>\n

Maintenance Schedule for Maximum Gearbox Life<\/h2>\n
\n\n\n\n\n\n\n\n\n\n
Intervalo<\/th>\nTask<\/th>\nNotes<\/th>\n<\/tr>\n<\/thead>\n
Antes de cada uso<\/td>\nCheck oil level via sight glass or dipstick<\/td>\nTop up if below minimum mark<\/td>\n<\/tr>\n
Every 50 hours<\/td>\nInspect seals for leaks, clean breather vent<\/td>\nReplace breather if clogged<\/td>\n<\/tr>\n
Every 100 hours<\/td>\nDrain and replace gear oil<\/td>\nUse EP 80W-90 or manufacturer spec<\/td>\n<\/tr>\n
Cada 200 horas<\/td>\nCheck input shaft spline for wear, measure gear backlash<\/td>\nReplace shaft if backlash > 0.015 in.<\/td>\n<\/tr>\n
Fin de temporada<\/td>\nFull inspection: bearings, seals, housing cracks, mounting bolts<\/td>\nStore with fresh oil to prevent corrosion<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

A disciplined maintenance routine is the single cheapest way to extend gearbox life. Most agricultural gearbox failures are preventable with basic fluid management and seasonal inspection. Skipping a single oil change rarely causes immediate damage, but it accelerates wear that compounds over time and shortens service life by 30% or more.<\/p>\n

<\/p>\n

Five Key Factors for Selecting the Right Gearbox<\/h2>\n

When sourcing a replacement or specifying a new rotary cutter gearbox, evaluate these five parameters before comparing prices:<\/p>\n

<\/p>\n

\n
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\u2705<\/span><\/p>\n

Tractor PTO speed and horsepower<\/strong> \u2014 Match the gearbox input rating to your tractor. A 540 RPM rated gearbox connected to a 1000 RPM PTO will over-speed the gears. Confirm whether your tractor has a 540, 540E (economy), or 1000 RPM PTO output.<\/p>\n<\/div>\n

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\u2705<\/span><\/p>\n

Gear ratio for the application<\/strong> \u2014 Light pasture work uses a 1:1 ratio; heavy brush clearing demands 1:1.92 or higher. Mismatching the ratio to the workload is the most frequent sizing error.<\/p>\n<\/div>\n

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\u2705<\/span><\/p>\n

Output shaft diameter and rotation direction<\/strong> \u2014 Replacement gearboxes must match the existing output shaft diameter and blade rotation direction (CW or CCW viewed from below). Reversing direction changes the debris discharge pattern and creates a safety hazard.<\/p>\n<\/div>\n

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\u2705<\/span><\/p>\n

Mounting bolt pattern and housing dimensions<\/strong> \u2014 The gearbox must bolt directly onto the existing cutter deck. Measure bolt circle diameter, hole count, and housing height. Even a 5 mm discrepancy requires adapter plates.<\/p>\n<\/div>\n

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\u2705<\/span><\/p>\n

Protecci\u00f3n contra sobrecarga<\/strong> \u2014 For rocky environments, choose a gearbox with a shear bolt or integrated slip clutch. The cost of replacing a shear bolt is negligible compared to rebuilding a gearbox.<\/p>\n<\/div>\n<\/div>\n

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\"Dimensi\u00f3n<\/div>\n

Dimensional reference for standard rotary cutter gearbox mounting configurations<\/p>\n<\/div>\n

<\/p>\n

Rotary Cutter Gearbox vs. Rotary Mower Gearbox<\/h2>\n

These two gearbox types are frequently confused but serve different purposes. Understanding the distinction prevents costly mis-specification.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Caracter\u00edstica<\/th>\nRotary Cutter<\/th>\nRotary Mower<\/th>\n<\/tr>\n<\/thead>\n
Primary use<\/td>\nBrush, saplings, rough terrain<\/td>\nTurf, grass, finished mowing<\/td>\n<\/tr>\n
Relaci\u00f3n de transmisi\u00f3n t\u00edpica<\/td>\n1:1,47 a 1:2,4<\/td>\n1:1 a 1:1.2<\/td>\n<\/tr>\n
Blade tip speed<\/td>\nLower (more torque)<\/td>\nHigher (cleaner cut)<\/td>\n<\/tr>\n
Impact rating<\/td>\nHeavy duty + overload protection<\/td>\nLight to medium duty<\/td>\n<\/tr>\n
Material de vivienda<\/td>\nDuctile iron \/ cast steel<\/td>\nCast iron \/ aluminum<\/td>\n<\/tr>\n
Typical HP range<\/td>\n25\u2013150+ HP<\/td>\n15\u201360 HP<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

A Caja de engranajes de la segadora rotativa<\/a> spinning at a 1:1 ratio will not survive the impact loads of brush cutting. Conversely, a heavy-duty rotary cutter gearbox on a finish mower wastes energy and adds unnecessary weight. Match the gearbox to the job, not to the tractor.<\/p>\n

<\/p>\n

PTO Shaft Compatibility and Driveline Setup<\/h2>\n

El eje de la toma de fuerza<\/a> connecting your tractor to the gearbox is just as critical as the gearbox itself. A worn or improperly sized driveline introduces vibration, accelerates spline wear, and can separate during operation \u2014 creating a serious safety hazard. Confirm these parameters before connecting:<\/p>\n

<\/p>\n

\n
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\ud83d\udcd0<\/span><\/p>\n

Spline count and diameter<\/strong> \u2014 Must match both the tractor PTO stub and gearbox input shaft. Most common: 6-spline 1-3\/8 in. (540 RPM) and 20-spline 1-3\/4 in. (1000 RPM). Some European tractors use 21-spline.<\/p>\n<\/div>\n

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\ud83d\udccf<\/span><\/p>\n

Driveline length<\/strong> \u2014 Minimum slip joint overlap should be at least 6 inches (150 mm) at maximum extension. Excessive overlap can cause binding during tight turns.<\/p>\n<\/div>\n

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\ud83d\udcd0<\/span><\/p>\n

U-joint working angles<\/strong> \u2014 Should not exceed 25\u00b0 during normal operation. Steeper angles increase joint wear exponentially and create cyclic speed variations (Cardan error) that stress gearbox input bearings.<\/p>\n<\/div>\n<\/div>\n

\"Caja\u00a0<\/p>\n

Manufacturing Quality: What Separates Reliable from Disposable<\/h2>\n

Price differences between rotary cutter gearboxes are not arbitrary. They reflect measurable differences in materials, machining precision, and quality control. Here is what to evaluate:<\/p>\n

Gear material and heat treatment determine tooth surface hardness and core toughness. Quality manufacturers use 20CrMnTi or 8620 alloy steel with carburized and case-hardened teeth, achieving surface hardness of HRC 58\u201362 while maintaining a tough, shock-absorbing core. Budget gearboxes often use through-hardened medium carbon steel with lower surface hardness, which wears faster under impact.<\/p>\n

Machining precision \u2014 specifically gear tooth profile accuracy \u2014 controls noise, vibration, and load distribution. Gears ground or lapped to AGMA Quality 10+ run quieter and distribute load more evenly than hobbed-only gears at AGMA 7 or 8. You can often hear this difference: a well-made gearbox hums quietly under load, while a poorly-made one whines or growls.<\/p>\n

Every PTO gearbox leaving a responsible manufacturer’s facility should undergo 100% testing \u2014 run-in under load, checking for noise, vibration, oil temperature rise, and seal integrity. If you are evaluating a new supplier, Contacta con nuestro equipo de ingenier\u00eda.<\/a> to discuss quality benchmarks and testing protocols.<\/p>\n

\"Taller<\/div>\n

<\/p>\n

Compatibilidad de reemplazo entre marcas<\/h2>\n

Many rotary cutter owners need to replace a worn gearbox on equipment from brands such as Bush Hog, Rhino, Land Pride, Schulte, John Deere, Woods, and Servis. Aftermarket gearboxes can match the mounting pattern, gear ratio, and shaft configuration of units originally supplied on these machines. These names are mentioned solely for cross-reference \u2014 they remain the registered trademarks of their respective owners.<\/p>\n

When cross-referencing, confirm mounting bolt circle diameter, housing height, input shaft spline count, output shaft diameter, and rotation direction. A reliable supplier will cross-reference by OEM part number and verify dimensional compatibility before shipping. You can browse the Caja de engranajes de toma de fuerza Ever-Power<\/a> catalog to find compatible replacements by application type and gear ratio.<\/p>\n

\"Tipos<\/p>\n

Preguntas frecuentes<\/h2>\n
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\nWhat oil should I use in my rotary cutter gearbox?+<\/span><\/summary>\n
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Use an EP (extreme pressure) gear oil rated 80W-90 unless the manufacturer specifies otherwise. EP additives protect the spiral bevel gear teeth under high contact pressures. Avoid standard motor oil \u2014 it lacks the film strength needed for gear tooth contact.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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\nHow do I know if my gearbox gear ratio is correct?+<\/span><\/summary>\n
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If your cutter stalls frequently in moderate brush, the ratio may be too high (not enough torque). If blade tip speed feels excessive and debris throws aggressively, the ratio may be too low. Check the nameplate or count teeth: divide input gear teeth by output gear teeth.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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\nCan I use a 1000 RPM gearbox on a 540 RPM tractor?+<\/span><\/summary>\n
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No. The input shaft spline dimensions differ (6-spline 1-3\/8 in. for 540 RPM vs. 20-spline 1-3\/4 in. for 1000 RPM), so physical connection is impossible without an adapter. Even then, running at 540 RPM delivers only about half the designed blade speed and torque.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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\nWhy does my gearbox leak oil from the output shaft?+<\/span><\/summary>\n
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The most common cause is a plugged breather vent. When the gearbox heats up, trapped air pressure forces oil past the seals. Clean or replace the breather first. If the leak persists, the seal lip may be worn or the shaft journal surface scored.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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\nHow long does a rotary cutter gearbox last?+<\/span><\/summary>\n
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With proper maintenance, a quality unit delivers 3,000\u20135,000+ operating hours. Budget units with lower-grade materials may fail within 500\u20131,000 hours. The upfront cost difference is minor compared to downtime and replacement expense.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

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\nWhat is the difference between a rotary cutter gearbox and a flail mower gearbox?+<\/span><\/summary>\n
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A Caja de engranajes de la desbrozadora de martillos<\/strong> typically uses a higher output speed (closer to 1:1 ratio) because flail mowers rely on many small hinged blades at high speed. They face continuous small impacts rather than occasional heavy ones, and use more robust seal technology against fine debris.<\/p>\n<\/div>\n<\/details>\n<\/div>\n

<\/p>\n

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Get a Custom Quote in 24 Hours<\/h2>\n

Whether you need a single replacement gearbox or a bulk OEM supply agreement for caja de cambios agr\u00edcola<\/a> production, our engineering team delivers precision solutions backed by 20+ years of manufacturing expertise.<\/p>\n

Contacta con nuestros ingenieros<\/a><\/p>\n<\/div>\n<\/div>\n

 <\/p>","protected":false},"excerpt":{"rendered":"

PTO Gearbox for Rotary Cutters: Complete Guide Over 73% of rotary cutter downtime traces back to gearbox-related failures. This guide covers every factor that determines whether your gearbox lasts one season or ten. Get a Custom Quote in 24 Hours What a Rotary Cutter Gearbox Actually Does A gearbox for rotary cutters sits between your […]<\/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":[4042],"tags":[3,6,4],"class_list":["post-1149","post","type-post","status-publish","format-standard","hentry","category-agricultural-gearbox","tag-agricultural-gearbox","tag-agricultural-pto-gearbox","tag-pto-gearbox"],"_links":{"self":[{"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/posts\/1149","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/comments?post=1149"}],"version-history":[{"count":3,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/posts\/1149\/revisions"}],"predecessor-version":[{"id":1180,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/posts\/1149\/revisions\/1180"}],"wp:attachment":[{"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/media?parent=1149"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/categories?post=1149"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pto-gearbox.net\/es\/wp-json\/wp\/v2\/tags?post=1149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}