Resumen rápido: La holgura de la cuchilla de cizalla se establece entre el 5 y el 10% del espesor del material, medido en el punto de corte. Para un acero dulce de 6 mm, esto significa una separación de 0,30 a 0,60 mm, pero el porcentaje es un rango de inicio, no una respuesta definitiva. Confirme el valor de trabajo con un corte de prueba en su material real, verifique la holgura en tres puntos a lo largo de la cuchilla con una galga de espesores y considere cualquier altura de rebaba superior al 5% del espesor como un indicador para volver a comprobar la separación.
Nota de ingeniería: La holgura de la cuchilla de cizalla es el espacio perpendicular entre los filos de corte superior e inferior, expresado como un porcentaje del espesor del material. Determina la relación entre la zona bruñida y la fracturada en el borde de corte, la altura de la rebaba y la carga de la cuchilla por golpe. El flujo de trabajo de configuración y control de calidad de Maxtor Metal trata la holgura como un parámetro de proceso específico para cada material —y no como un ajuste fijo de la máquina— y la documenta por trabajo junto con el estado de la cuchilla y las lecturas del radio del borde.[→ See Maxtor Metal shear blade specifications and material options]
La holgura de la cuchilla de cizalla es la separación horizontal entre los filos de corte superior e inferior en el punto de corte, y en una cizalla de guillotina normalmente se establece como un porcentaje del espesor del material en lugar de un número fijo. Cometer un error aquí tiene un costo que no es abstracto: el desperdicio de tira por mala calidad de borde representa entre el 5% y el 10% del costo total de propiedad, una cifra que se acumula en cada ciclo de rectificado.
The 5–10 percent rule is a starting range rather than a specification. Treat the machine manual as the authority, then find the working value by iterating on the actual sheet, blade sharpness and rake angle (Ursviken, 2025). Note the convention split: some suppliers state blade clearance per side, others state the blade-to-blade gap, so confirm which figure the Maxtor Metal shear blade specification uses before you dial anything in. Maxtor Metal works to the per-side reading, which doubles the number at the gap.
Puntos clave
- La holgura de la cuchilla de cizalla es un porcentaje del espesor del material, ajustado en el punto de corte.
- El rango del 5 al 10% es una banda de inicio; el manual de la máquina determina el valor final.
- Confirme si una cifra publicada corresponde a la holgura de la cuchilla por lado o a la separación total entre cuchillas.
- La mala calidad del borde genera entre el 5% y el 10% del costo total de propiedad debido al desperdicio de tira.
Nota sobre las fuentes: esta guía se basa en referencias publicadas sobre el corte por cizallado (las Directrices AHSS, la documentación del proceso de cizallado de ispatguru y las guías de fabricantes de equipos como Ursviken y Sureay), junto con la propia experiencia de taller de Maxtor Metal. Cuando una cifra procede de una fuente independiente, se cita como tal; cuando refleja el límite de aceptación interno de un fabricante, se indica claramente para que pueda sopesarlo adecuadamente.
Mecánica de los bordes de corte
Shear blade clearance decides how a cut fails, and that failure is what produces either a clean edge or a burr. The mechanism is worth understanding because it explains why the recommended band moves with material and thickness rather than staying fixed.
In short: clearance controls the split between smooth burnish and rough fracture on the cut edge — understanding this mechanism is what turns the 5–10% band from a guess into a tuning range.
Burnish and fracture zones
A sheared edge is not one surface. It is four zones stacked through the material thickness: rollover, where the blade first contacts and plastically deforms the sheet into a rounded, bent region; the burnish or shear zone, a smooth band formed while the blade compresses and rubs the material; the fracture or rupture zone, a rougher angled region where the crack propagates; and the burr, thin elongated metal pushed out at the exit edge (ispatguru, 2019; Directrices de AHSS, 2021).
Rollover and burr formation
Clearance sets the split between the smooth and rough portions of that edge. The burnish zone ends where crack initiation begins, so penetration depth equals rollover height plus burnishing zone height. The rough fracture zone then grows with ductility, thickness and clearance, which means a larger clearance shrinks the burnish share, enlarges the fracture share, and pushes more material into the burr (ispatguru, 2019).
Force, rake, and clearance interplay
The general shearing range runs from 2% to 10% of material thickness, and the correct point inside that range depends on the workpiece. Harder materials and greater thickness need larger clearance. Set it too wide and the edge comes out rounded and distorted with a burr and a higher shearing load; set it too tight and the blade leaves a double cut, sometimes called secondary shearing. Ductile material produces a taller burr at any given clearance (ispatguru, 2019).
That is the mechanism behind the band. The next section turns it into numbers.
La regla del 5–10%
The 5–10 percent rule says the shear blade clearance should sit between 5% and 10% of the metal thickness you are cutting. That band is the starting point for mild steels, not a universal setting, and the Directrices de AHSS note that published recommendations place mild-steel die clearance at 5% to 10% of metal thickness. The same source flags a convention trap worth settling before you touch the machine: for punched holes, those figures are per-side values. Vendor charts on the open web often frame the identical 5%–10% band as the total blade-to-blade gap instead. Confirm which convention your chart uses before you convert a number into a shim stack, because a 10 mm mild-steel cut reads as 0.5–1.0 mm per side under one reading and 0.5–1.0 mm total under the other.
In short: the 5–10% band is a defensible starting range for mild steel, not a universal answer — the working value must be confirmed by test cut on the actual material, and the convention (per side vs total gap) must be established before any number is set.
Material-based bands
The band widens as the material gets stronger. The AHSS Guidelines put the range at roughly 6% for mild steel, rising to 16% or higher once tensile strength passes 1400 MPa, and note that ISO 16630 hole-expansion testing specifies 12% punch-to-die clearance while optimal clearance for advanced high-strength steel appears to be approximately 15%. Treat those as directional anchors rather than a lookup table: they come from a technical body’s guidance program, and the underlying figure is a historical baseline rather than a recent test series.
For AHSS and UHSS applications where standard D2 blades are reaching their clearance and wear limits, see the guía de ROI de cuchillas de cizalla con insertos de carburo de tungsteno para líneas de AHSS para obtener una comparación completa del TCO.
When to deviate
Deviate upward when the material work-hardens or when edge quality matters more than tool life. Deviate downward only when your press capacity is the binding constraint, since tighter clearance raises cutting force. The honest position is that 5%–10% is a starting point you tune from, not an answer you inherit.
Parallelism and thickness effects
Clearance is only as good as its consistency along the blade. A machine set to 8% at the ends but drifting to 11% mid-blade will burr in the middle and shear cleanly at the edges, which is why parallelism is checked separately from the nominal gap. Thicker stock amplifies the same error: the absolute gap grows with thickness, so a fixed mechanical misalignment becomes a larger percentage deviation.
SOP de configuración
A repeatable shear blade clearance setup follows one sequence: baseline the gap, verify parallelism, lock, test cut, iterate. The steps below assume the machine is locked off, the blades are clean and correctly seated, and you have a feeler gauge set, a dial indicator with a magnetic base, and scrap of the material you are about to run. Budget 30 to 45 minutes for a first setup on a machine you do not know well.
In short: measure clearance at three points along the blade before every setup change, verify parallelism within 0.02 mm, lock the adjusters, then iterate from a test cut — the sequence matters because locking adjusters commonly shifts the gap.
Feeler gauge baseline
Set the upper blade to its lowest position and insert the feeler gauge stack at the left end, center, and right end of the blade. Three points is the minimum; add points every 500 mm on blades longer than 2 m. Adjust the gap until the gauge drags with light resistance rather than passing freely or binding. Record all readings before touching anything else, because the spread across those points tells you whether you are correcting clearance or parallelism.
Dial indicator calibration
Mount the dial indicator on the lower blade and sweep the upper blade through its stroke, recording readings at several positions along the length. Blades should sit within 0,02 milímetros of each other, and the gap needs immediate recalibration once it exceeds that. Note what kind of number this is: there is no single ISO standard that sets a shear-blade parallelism limit, so 0.02 mm is Maxtor Metal’s internal acceptance target, not an industry-mandated figure. The relevant general framework is dimensional and geometric tolerancing — ISO 286 defines the IT tolerance grades used for precision blade geometry (IT6 for cutting-edge position, parallelism to the holder reference face, and flatness; IT7 for length, width, and mounting-hole position), and ISO 2768 supplies general tolerances where a drawing carries no individual callout. Treat the 0.02 mm as a tighter-than-general shop specification built on that framework (ISO 286-1:2010; ISO 2768). The reason such a tight target is worth holding is mechanical: on a 3,000–4,000 mm blade, a 0.1–0.15 mm deviation across the length is enough to produce visible taper on the cut edge (consistent with precision blade geometry standards under ISO 286 / ISO 2768). Lock the adjusters and re-check the gap at the same three points; locking commonly shifts it.
Test cut and iteration
Run a slow test cut on scrap and read the edge. Burrs or tearing mean the gap is too large; rubbing or excessive tightness means it is too small. Change clearance in small increments and re-cut rather than adjusting several variables at once, then log the final gap, the material grade and thickness, and the indicator readings against the job number so the next setup starts from a known point.
Each regrind removes material from the blade thickness. For the shim calculation method that compensates for this dimensional change and restores correct overlap after each cycle, see the regrinding thickness reduction compensation and shim stack guide.
Verify your result: the test cut should shear cleanly with no visible taper along its length, and a repeat indicator sweep should hold the gap within 0.02 mm after the adjusters are locked.
Caso práctico: corrección de rebaba excesiva en S355 de 6 mm
The clearest way to see why 5–10% is a starting rule and not a fixed answer is to walk through a commissioning-style troubleshooting case. This is a representative field case built on documented industry practice rather than a measured customer study: the machine, material and measurement sequence reflect how this problem typically appears on a hydraulic guillotine shear, and the underlying rules — the 5–10% band, the ~10% structural-steel practice, and multi-point feeler-gauge verification — are all publicly documented.
In short: this case demonstrates that a clearance value can sit inside the published 5–10% range and still produce unacceptable edge quality — the percentage is the starting calculation, and the cut edge is the verification tool.
The situation
| Parámetro | Valor |
|---|---|
| Aplicación | Hydraulic guillotine shear |
| Material | S355 structural steel |
| Espesor nominal | 6.0 mm |
| Measured thickness | 5.94–6.06 mm across the test sheets |
| Cuchilla | Hardened cold-work tool-steel shear blades |
| Initial clearance | ~0.30 mm |
| Target window | ~0.30–0.60 mm (5–10% starting rule) |
The problem appeared after the machine was switched from thinner sheet to 6 mm structural steel. The operator kept the previous clearance setting rather than recalculating the gap from the new material thickness — a common error where clearance is treated as a fixed machine setting instead of a material-dependent process parameter. The first test cuts showed a noticeably larger burr on the underside of the cut edge, a relatively short burnished zone, and a more irregular fracture zone. The operator suspected dull blades and considered replacing them.
Attempt 1 — replace the blades (rejected)
The first response was to suspect blade wear. Inspection, however, showed the cutting edges were still serviceable — no significant chipping or abnormal rounding. Replacing the blades without correcting the clearance would have treated the symptom rather than the process condition, so the next step was to verify the actual gap.
Measurement sequence
The machine was stopped and isolated per the site’s maintenance procedure. Blade seats were cleaned and checked for trapped scale, chips and debris. Sheet thickness was measured at several points with a micrometer rather than trusting the nominal 6 mm designation. Clearance was then measured at the left, center and right portions of the cutting length with calibrated feeler gauges. The machine manufacturer’s definition of clearance was used throughout the adjustment. This multi-point approach follows published shear-machine guidance, which requires clearance verification at several points along the blade rather than assuming the machine’s nominal setting equals the actual gap — Mittler Bros. and other shear manuals specify checking left, center and right with feeler gauges, and the Australian Steel Institute notes that optimum clearance depends on both material properties and thickness.
Attempt 2 — keep the 5% setting (insufficient)
After measurement, the initial gap was approximately 0.30 mm — about 5% of the measured 6 mm thickness:
6.0 mm × 5% = 0.30 mm
That value was technically inside the general 5–10% starting range, yet edge quality remained unsatisfactory. This is the key point: a value can sit inside the published percentage range and still not be the optimum setting for a particular machine-and-material combination. Clearance is also affected by blade condition, blade geometry, machine rigidity, alignment, and the mechanical properties of the workpiece. Betenbender’s shear guidance makes the same observation for steel work — roughly 10% of thickness usually gives a good cut edge, and clearance may be increased for harder or thicker material, but not beyond about 15%.
Attempt 3 — increase clearance (resolved)
Clearance was increased progressively toward approximately 0.50–0.55 mm, corresponding to roughly 8–9% of the 6 mm material thickness, then a fresh test cut was made under the same material and machine conditions. Edge quality improved visibly. The important caveat: this is not a claim that 0.50 mm is universally correct for S355 — it is simply the working setting found in this troubleshooting example. Published material studies make the same point about clearance being material-specific: voestalpine’s ALFORM technical data compares 4%, 10% and 16% clearance on 3 mm ALFORM 700 M and shows the cut-section geometry changes markedly with the ratio, with excessive clearance increasing burr and edge denting while reducing the shearing-zone share.
Effect, recorded honestly
Rather than inventing precise burr-height numbers, a credible record notes the observable change:
| Parámetro | Initial condition | After adjustment |
|---|---|---|
| Material | S355 | S355 |
| Espesor nominal | 6 mm | 6 mm |
| Measured thickness | 5.94–6.06 mm | 5.94–6.06 mm |
| Autorización | ~0.30 mm | ~0.50–0.55 mm |
| Clearance ratio | ~5% | ~8–9% |
| Blade condition | Serviceable | Same |
| Test batch | Same heat / comparable material | Same |
| Rebaba | Pronounced / unacceptable | Visibly reduced |
| Cut edge | Irregular fracture zone | More uniform fracture |
| Blade change | Not required | Not required |
If a team wants to make this rigorous, the fields worth adding are burr height (mm), rollover height (mm), burnished-zone and fracture-zone percentages, cut-angle deviation, machine hydraulic pressure, number of strokes, and blade edge radius.
The takeaway: the 5–10% rule provided the starting window; the test cut identified the working point. The percentage is the starting calculation — the cut edge is the verification tool.
This chain is worth internalising: 5–10% rule → 6 mm S355 gives a 0.30–0.60 mm starting window → measurement shows 0.30 mm gives poor edge quality → step up to ~0.50–0.55 mm → test cut confirms the improvement → do not market 0.50 mm as a “standard value” → every material, thickness and machine combination must be verified by test cut. The AHSS Guidelines reinforce why: clearance is not an isolated variable — a smaller clearance raises cutting force and the demands on tool and machine alignment, while a larger clearance increases rollover and related effects.
Control de calidad y mantenimiento
In short: set a numeric burr height limit before the job starts, log clearance and material lot per job, and treat rising burr height or an edge radius above 0.2 mm as mandatory regrind triggers — not subjective judgements.
Burr height limits and triggers
Burr height is the fastest field check on a shear, and it is the one most often left unmeasured. Set a numeric limit before the job starts, then treat any exceedance as a trigger rather than a nuisance.
A practical default is 5% of material thickness. On 3 mm mild steel that is 0.15 mm, measurable with a deburring gauge or a bench micrometer across the burr crest. Project drawings and customer acceptance criteria override the default whenever they are tighter.
Two triggers should stop the line:
- Burr height above tolerance on two consecutive cuts after a clearance check.
- Edge radius at or above 0.2 mm, measured on the blade bevel with a radius gauge or a 20× magnifier.
The second trigger matters because edge rounding, not visible chipping, is what silently widens the effective clearance. A blade that looks serviceable can already be cutting 0.05 mm wider per side than the setup sheet says. As with the parallelism target, the 0.2 mm is a Maxtor Metal internal limit rather than an ISO-mandated value; published edge-radius ranges for industrial blades vary widely by application — some slitting guides cite 0.05–0.30 mm, disc-shear references hold below 0.05 mm, and general deburring practice references edge-break specifications such as ISO 13715. That spread is exactly why you set the limit against your own acceptance criteria rather than assuming one number fits every line.
For a measurement-based rotation trigger and audit-ready log template that standardises this decision across an entire blade inventory, see the SOP de programa de rotación de cuchillas reversibles de 4 filos y criterios de reafilado.
Consejo profesional: Log clearance, material lot, and burr height per job in one sheet. After a few weeks the log shows whether drift tracks a specific material lot, a specific operator, or the blade itself, which turns regrind scheduling from guesswork into a trend line.
Defect diagnosis and corrective actions
Match the defect to the cause before touching the blade. Most burr and edge complaints trace back to one of four conditions, and each has a different fix.
| Defecto | Causa probable | Acción correctiva |
|---|---|---|
| Tall, rolled burr on one side | Clearance too wide on that side | Re-check parallelism, reduce gap toward the lower band |
| Short, brittle burr with edge chipping | Clearance too tight | Open the gap, inspect the bevel under 20× magnification |
| Burr varies along the cut length | Blade not parallel or ram misalignment | Re-shim and verify straightness before the next setup |
| Clean cut, sudden burr spike mid-run | Edge wear or chipping | Measure edge radius, then decide regrind or replace |
When chipping appears suddenly or in a consistent location along the blade, the defect pattern itself carries diagnostic information. For a fracture surface analysis workflow that identifies whether the root cause is fatigue (clearance or grinding error) or impact (overload or hardness mismatch), see the shear blade edge chipping root cause guide.
That last decision follows a chipping-depth ladder. Light chipping under 0.2 mm clears with standard stock removal of 0.25–0.35 mm. Moderate chipping between 0.2 mm and 0.5 mm needs deeper removal and a 20× inspection of the bevel. Severe chipping above 0.5 mm means scrap or a major removal that can push the blade past its dimensional safety limit. The floor on any regrind is 0.254–0.381 mm of stock removal, because micro-fractures from running a blade past its sharpening window penetrate 0.25–0.40 mm below the bevel and will surface again if that layer is left in place (Maxtor Metal regrind-or-replace criteria for shear blades, retrieved 2026-08-27).
For a full analysis of how D2 and SKD11 carbide microstructure affects chipping depth and regrind frequency, see the D2 vs SKD11 tool steel shear blade selection guide.
Maxtor Metal’s own QC workflow ties this together: blades are logged against job and material lot, regrind is triggered when edge radius reaches 0.2 mm or burr height exceeds project tolerance, and every returned blade is re-verified for straightness under 0.02 mm/m, parallelism under 0.015 mm, and hardness across the full length before it goes back into rotation. These too are internal acceptance limits, set tighter than the general ISO 2768 / ISO 286 framework rather than drawn from a single published shear-blade standard. The point of the record is not the paperwork. It is knowing which of your four-edge reversible blades still has usable edges and which one is one bad cut away from a scrap decision.
FAQs:
P: ¿Qué es la regla del 5–10 por ciento para la holgura de la cuchilla de cizalla?
R: Establece la holgura de la cuchilla de cizalla entre el 5% y el 10% del espesor del material. Para un acero dulce de 10 mm, esto es de 0,5 a 1,0 mm. El margen se reduce a medida que aumenta la resistencia a la tracción: el aluminio blando se sitúa cerca del límite superior, mientras que el acero inoxidable y el HSLA se ubican cerca del inferior. Considere esto como un punto de partida y confírmelo con un corte de prueba en el lote de material real.
P: ¿La holgura de la cuchilla de cizalla es por lado o total?
R: Ambas convenciones aparecen en las tablas publicadas, y mezclarlas duplica su separación. Maxtor Metal especifica su recomendado 5–10% como holgura de la cuchilla por lado; por lo tanto, un corte de acero dulce de 10 mm funciona con 0,5–1,0 mm por lado, o 1–2 mm en total. Verifique qué convención utilizó el fabricante de su máquina antes de ajustar nada.
P: ¿Qué holgura debo ajustar para acero dulce de 6 mm?
R: Comience con 0,3–0,6 mm y verifique mediante el borde de corte. Un borde limpio y recto con una ligera banda de bruñido indica que está cerca del valor correcto; un redondeo pronunciado o una rebaba irregular significan que la separación es demasiado ancha. Mida la rebaba en lugar de juzgarla a simple vista.
P: ¿Puedo usar la misma holgura para el acero inoxidable y el acero dulce?
R: No. El acero inoxidable, el HSLA y otros grados de mayor resistencia necesitan una separación más ajustada, generalmente hacia el extremo inferior del rango, debido a que resisten el flujo plástico y se fracturan antes. Aplicar la holgura del acero dulce en el acero inoxidable produce agrietamiento en el borde y un desgaste acelerado de la cuchilla.
P: ¿Con qué frecuencia se debe rectificar una cuchilla de cizalla?
R: La altura de la rebaba es el indicador práctico: la práctica habitual apunta a mantener la altura de la rebaba por debajo del 10% del espesor del metal, y el aumento de la rebaba refleja tanto el desgaste de la herramienta como el incremento de la holgura (Directrices AHSS). Para los aceros avanzados de alta resistencia (AHSS), la altura de la rebaba por sí sola es una señal débil, por lo que la calidad del borde de corte es un mejor indicador. El flujo de trabajo propio de Maxtor Metal utiliza un radio de filo de 0,2 mm o una altura de rebaba que supere la tolerancia del proyecto, lo que ocurra primero.
P: ¿Cómo verifico el paralelismo de la cuchilla de cizalla?
R: Utilice un indicador de carátula sobre una base magnética, recorriendo toda la longitud de la cuchilla con la máquina bloqueada y apagada. Maxtor Metal verifica una rectitud inferior a 0,02 mm/m y un paralelismo inferior a 0,015 mm durante la fabricación; estos son límites de aceptación internos basados en el marco general de tolerancia ISO 2768 / ISO 286, por lo que representan un punto de referencia razonable para una máquina en servicio, más allá de ser una cifra exigida por cada norma estándar. Vuelva a comprobarlo después de cualquier rectificado o cambio de cuchilla.
P: ¿Por qué mi cizalla deja un corte doble?
R: Un corte doble usually significa que la holgura es demasiado ancha para el espesor, por lo que el material se dobla hacia el espacio y se fractura dos veces en lugar de una. También puede deberse a una fuerza de sujeción insuficiente o a una cuchilla que ha perdido su filo. Ajuste la holgura hacia el extremo inferior del rango y compruebe la presión de sujeción antes de culpar a la cuchilla.
Conclusión
La holgura de la cuchilla de cizalla es una decisión de configuración, no un número fijo, y la regla del 5–10% le ofrece un punto de partida defendible más que una respuesta universal. Este margen controla dos cosas a la vez: cuánta zona bruñida y fracturada experimenta el borde, y cuánta caída de canto (rollover) y rebaba deja el corte. Si acierta, la cara de corte se mantiene limpia; si se desvía de este rango, cambiará un defecto por otro.
Lo que separa un proceso controlado de uno basado en la suerte es la estandarización. Registre la holgura configurada para cada trabajo, anote el grado y el espesor del material para el cual se estableció, y compruebe el estado del borde a intervalos fijos en lugar de esperar a recibir una queja por rebabas. Haga un seguimiento de los ciclos de rectificado en función de esos registros para poder ver el desgaste del filo antes de que falle. Considere esto tanto un problema de flujo de trabajo como un tema de cuchillas: el mismo valor de holgura se comporta de manera diferente entre turnos si nadie lo pone por escrito.
Si está configurando una nueva cizalla o estandarizando una existente, revise la especificación de la cuchilla en función de su combinación de materiales y su ciclo de trabajo antes de comprometerse con un valor numérico. Cuando el material o la aplicación se encuentran fuera de los rangos habituales, consulte a un ingeniero de aplicaciones sobre dónde debe desviarse su proceso y por qué.
For the full Maxtor Metal shear blade range — material grades, dimensional tolerances, and regrind service options — see the precision shear blade product page.
This guide is written and reviewed by Jerry Chu, Technical Support Specialist in Maxtor Metal’s After-sales Service team. Jerry has 10 years of hands-on experience with industrial cutting blades across paper making, plastic granulation, metal slitting and slitting lines, and wood processing — applications where burr formation, edge quality, and dust generation all show up as real production problems rather than theory. That field background shapes the setup and QC guidance here: the focus on measurable triggers (burr height, edge radius, parallelism) rather than subjective “looks fine” judgements comes directly from troubleshooting these issues on customer lines.
Jerry holds PMP (Project Management Professional) y CMRP2 certifications, which support the process-discipline approach — logging, standardised setup, and scheduled inspection — that runs through this article.
Maxtor Metal is a manufacturer and supplier of custom, precision-ground industrial blades with over 15 years of experience, serving engineers, technical buyers, and equipment manufacturers worldwide. The company operates a quality management system certified to ISO 9001, and manufactures blades to customer drawings, sketches, or photos with material selection aimed at extending blade life. The internal tolerance and regrind figures quoted in this article come from that QC workflow.
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