高精度スリッター用スペーサー＆ゴムリング：組込み剛性、刃先クリアランス、およびTIR（総合振れ精度）の完全制御

本稿で得られる知見： 寸法・形状公差、軸系セットアップ手順、精度検証方法、およびROI（投資対効果）管理シート。要求すべき具体的な寸法公差・仕様、シャフト締め付け（クランプ）前に実行すべき検収項目、そして「刃具のアップグレード」を数値化可能な設備稼动率（アップタイム）へと昇華させるためのデータ管理手法。

高速コイルストリップのスリッター加工において、不具合（製品のバリや破断面の悪化）が発生する原因は、通常「刃物の品質不良」ではありません。真の原因は、シャフト締め付け（クランプ）、加速、摩擦熱の発生、そして通板荷重（ストリップロード）による横方向への押し付け力が加わった際、当初設定したはずの刃先クリアランスを軸系（スタック）が死守できていないことにあります。

常時一定の軸向サイドクリアランス（横隙）とスタック組込み剛性が、製品の「バリ高さ（毛刺）」、「エッジウェーブ（耳波・エッジのうねり）」、そして刃物の「早期チッピング（微小崩刃）」の発生率と直結している理由はここにあります。もし、負荷がかかった際に軸系が「呼吸（微小な逃げ・ガタつき）」してしまうようでは（スペーサーの数ミクロンの平行度誤差、ゴムリングのへたり、座面の打痕など）、刃先クリアランスは常に変動する不安定なものになってしまいます。

If you’re running rotary slitting / roller shearing knife sets, the same fundamentals show up in the blade geometry and tolerance discussions on Maxtor Metal’s page for 金属用ロータリーシャーリングブレード: clearance and runout targets are always written as process windows—because the machine only performs as well as the stack-up discipline.

• Why constant axial side‑clearance and stack stiffness control burr, edge quality, and blade life: stable clearance keeps the fracture zone and shear zone where you expect them, rather than drifting into tearing or overload.
• How precision slitting spacers and rubber rings act together under load at speed: spacers create a rigid geometry; rings add controlled preload and damping so the geometry stays put dynamically.

刃先サイドクリアランス（横隙）の力学メカニズム

Fracture–shear meeting point

Rotary slitting is a controlled failure. The clean part of the edge comes from shearing; the burr and raggedness come from fracture and tearing. Your job is to keep that transition consistent along the coil.

When horizontal clearance is too loose, the strip tends to stretch and tear around the knives, which pushes burr up. When it’s too tight, cutting forces rise and operators often compensate by driving more overlap—another path to burr and damage. Trade guidance such as The Fabricator’s discussion of “slit-in” coil slitting problems ties edge defects directly to clearance and overlap discipline.

The practical takeaway: you can’t judge side-clearance only at standstill. What matters is clearance under load, because that’s what defines whether you stay in a shear-dominant regime or drift into tearing.

Assembly stiffness dynamics

A slitting stack is a spring system. One practical way to think about it is slitter knife stack stiffness: how much the whole pack resists micro-movement once it’s clamped and loaded.

• the arbor and hubs flex
• the knives act like thin rings that can deflect
• the spacer pack transmits clamp load
• rubber rings (when used) behave like compliant preload elements

At speed, even small stiffness losses show up as clearance variation. Once clearance varies, you get asymmetric loading on the knife corners—one side is overloaded, the other isn’t working—so wear patterns accelerate and micro-chipping becomes more likely.

重要なポイント: If your burr is inconsistent across lanes or drifts over a run, treat it as a stiffness/stack-up problem before you treat it as a “knife material” problem.

Role of precision slitting spacers

Precision slitting spacers do two jobs that basic shims can’t reliably do:

1. Lock the geometry: thickness, parallelism, and seating quality keep the knife faces square to the arbor axis.
2. Keep the stack repeatable: you can break down and rebuild without “tuning by feel” every shift.

In other words, spacers are what make side-clearance a controlled parameter rather than a habit.

高精度スリッター用スペーサーの技術仕様・寸法公差

Where this section fits: When people search for precision slitting spacers, they’re usually trying to eliminate thickness drift and clearance variation—so the spec has to be explicit and measurable.

Thickness and parallelism

Thickness tolerance is only half the story. Parallelism (and the cleanliness of the faces that establish it) is what prevents your knife faces from “walking” under load.

A practical way to specify this in procurement language:

• Thickness tolerance appropriate to your slit width tolerance and lane count (tighter stacks amplify small errors).
• Parallelism/flatness targets consistent with the line’s edge-quality requirement.

In multi-knife work, cumulative error is real. If you want a practical starting point for what published knife sets can hold, Maxtor Metal’s roller shearing blades page includes examples of tight thickness/parallelism targets for rotary slitter knives—useful as context when you’re setting expectations for the spacer pack as well.

If your drawings rely on general tolerances, referencing ISO 2768‑1:1989 general tolerances is one way to standardize “default” expectations for non-critical dimensions (so suppliers interpret unspecified dimensions consistently). For fit-critical diameters, a limits-and-fits system such as ISO 286‑1:2010 provides the standard framework.

In procurement terms, ISO 286 helps you specify tolerance zones for hole/shaft systems (the notation on drawings defines the allowable size range and the intended fit). Whatever system you use, make it auditable: tie spacer/knife/arbor fits to a measurable inspection plan (bore/shaft measurements, runout checks, and a retained inspection record).

Runout and arbor fit

Side-clearance is only as stable as the stack’s seating and fit on the arbor.

If the spacer bore fit is sloppy, you can build runout into the stack even if every individual part measures “in spec” on a bench. For fit language, ISO 286‑1 gives the standard framework used to define hole/shaft tolerance systems.

What to do in practice:

• Use a consistent fit strategy for spacers, knives, and arbors.
• Inspect seating faces for burrs, dents, and fretting marks—small defects create effective runout.
• Treat any repeated “mystery burr” as a reason to check axial runout at the knife OD, not only thickness.

For the ISO fit class selection, TIR acceptance tiers, and blue-check protocol that define a complete spindle fit verification, see the OEMスリッターナイフの図面：スピンドル嵌合監査、ISO公差、TIRゲート.

Material and identification

Spacer materials and surface condition matter because they affect wear, fretting, and long-term repeatability.

Minimum identification discipline for a production environment:

• each spacer set is labeled by thickness and lane position
• damaged parts are quarantined (not “put back in the box”)
• measurement records are tied to a lot or serial so drift can be traced

That traceability mindset is also what procurement teams expect when the line is under ISO-driven quality systems.

ゴムリング（ストリッパーリング）の適正配置・芯出し設定

Durometer and sizing

Rubber rings are often treated as consumables, but in a high-speed slitting head they function like a preload and damping element.

• Durometer affects how much the ring deforms under clamp load and how stable that load remains during heat and time.
• Sizing (cross-section and ID/OD relationship to the stack) affects whether the ring compresses uniformly or extrudes into gaps.

A useful rule: choose rings as if you were selecting a critical machine element, not a generic seal.

A practical way to start durometer selection is to treat it as a balance between preload stability (too soft → clamp load decays sooner) and heat/energy management (too hard → less damping, more marking risk).

Ranges depend on OEM arbor design, clamp method, stack format, temperature, and lubricant exposure. Use first-off validation and burr/runout trends to confirm your working window.

If you’re troubleshooting rotary slitter side clearance drift, ring selection is worth checking as carefully as spacer thickness—because loss of preload shows up as clearance variation before it shows up as a visibly failed ring.

Target compression window

A practical setup mindset is to treat this as rubber ring compression slitting: you’re using controlled squeeze to hold and damp the stack, not to “crush” it.

You don’t need a single universal “best” compression number to run a disciplined setup. You need a repeatable compression window that:

• provides enough preload to stabilize the stack
• avoids over-squeezing that accelerates heat build-up and permanent set
• stays consistent across lanes

As a directional starting point, in many steel coil slitting configurations a target compression window of ~5–12% of the ring’s free cross-section thickness is commonly used. Adjust based on ring material (NBR/PU/TPU), clamp method, stack format, and thermal environment.

In general elastomer engineering, too much sustained compression increases the risk of permanent deformation (compression set) and early loss of recovery. ASTM’s legacy work on elastomer seals under sustained compression is a good reminder that squeeze is not “free”—it changes long-term behavior.

Failure modes and fixes

Most ring problems show up as clearance instability, not as an obvious “broken part.” Common patterns:

• Compression set (ring takes a set) → preload decays; burr slowly increases or becomes inconsistent.
  • Fix: replace rings on a cadence; avoid overheating; verify clamp procedure.
• Extrusion into gaps → ring edges shear or smear; debris appears; stack loses repeatability.
  • Fix: correct sizing, reduce clearance gaps, confirm ring position and support.
• Swelling/chemical attack → ring dimensions change; clamp load becomes unpredictable.
  • Fix: verify compatibility with lubricants/coolants; isolate rings from aggressive fluids.
• Heat aging/hardening → ring loses damping; vibration marks or noise increases.
  • Fix: adjust material selection; keep temperature under control; improve housekeeping.

These show up operationally as coil slitting burr control becoming unstable: the same nominal settings produce different burr height across lanes or over time.

軸系セットアップおよび精度検証

Pre‑clamp checks

Before you clamp the stack, do the checks that prevent 80% of “why did the burr spike?” problems:

• faces are clean, dry, and free of nicks
• spacer IDs and knife bores are free of galling and fretting dust. If your team doesn’t yet have a standardized spindle inspection record, the arbor bore and runout audit template provides a structured logging format covering ISO fit class, TIR readings, and blue-check results.
• rings are free of cracks, glazing, and permanent flattening
• the arbor and keying surfaces are clean and undamaged

Clearance preset and logging

Treat side-clearance as a controlled parameter, not a tribal memory.

Log these fields every time you build or adjust the head:

• material grade and thickness
• target side-clearance and overlap setting (your baseline window)
• measured axial runout at knife OD (as-built)
• ring durometer/spec and installation date
• torque/clamp method and any deviations

This is where Maxtor Metal can fit naturally into a disciplined process: calibrated spacer supply (with consistent thickness/parallelism), practical ring selection support based on your material range and line speed, and compatibility notes so spacer and ring choices match common OEM arbors and knife formats.

Why trust Maxtor Metal (quality, traceability, and delivery)

If you’re using precision spacers and rubber rings as process components—not “hardware in a box”—you also need suppliers who can document what they ship.

Maxtor Metal can support that documentation with:

• Material control: raw materials from qualified long-term steel suppliers; MTC (Material Test Certificate) available upon request for applicable materials; incoming material checked against purchase specifications.
• Process control: heat treatment selected by steel grade and application; hardness verified after heat treatment before finish grinding.
• Dimensional inspection capability (per drawing requirements): thickness, OD/ID, parallelism/flatness, concentricity (where applicable), radial/axial runout, and cutting edge profile.
• Inspection documents available based on requirement: dimensional inspection report, hardness test report, shipment inspection report, and FAI (First Article Inspection).
• Traceability: internal batch number links manufacturing and inspection records; records retained under document control procedures.
• Nonconforming product control: isolation, re-inspection, root-cause analysis when required, and corrective actions before resuming production.
• Typical lead times (actual varies by size/material/complexity): standard samples 7–15 working days, customized samples 10–20, small orders 15–25, regular production 20–35.
• Packaging and corrosion protection: rust preventive oil, anti-corrosion paper, individual protection, moisture-resistant packaging; vacuum packing on request; export cartons/wooden cases for larger blades.
• Technical support: drawing review, material selection, replacement blade sampling, installation/maintenance suggestions, and follow-up on performance issues with corrective actions when applicable.

First‑article validation

Don’t wait for a customer complaint or a full-coil scrap event. Validate on the first article:

• inspect burr height and edge rollover at a defined sampling interval
• confirm strip width vs tolerance (especially across outside lanes)
• listen for abnormal noise or rhythmic marking that suggests runout or ring instability

If you adjust, record what changed and why. Over time, this builds a parameter library tied to coil grades and speeds.

ケーススタディ（匿名化）：スペーサー端面精度とゴムリング圧縮率の標準化による改善効果

Below is an anonymized field example to show what “stack discipline” can look like when it’s measured and standardized. Numbers are shown as ranges (conservative reporting). Your results will depend on arbor condition, overlap, incoming coil flatness, and operator consistency.

Production background

• 材料: Q235 cold rolled steel (EN DC01 equivalent)
• 厚さ: 1.2 mm
• Slitting pattern: 12 strips; finished width 85 ±0.10 mm
• Line speed / throughput: 140–180 m/min; ~160–190 tons/shift
• Tooling: slitter knife OD 220 mm × ID 120 mm × 10 mm; arbor Ø120 mm; precision steel spacers + bonded PU stripper rings

Baseline (before)

• Burr height: 18–32 μm
• Knife life: 1,050–1,300 tons between regrinds
• Unplanned downtime: 5–7 stoppages/month (often associated with strip tracking instability and burr growth)

What changed

1) Spacer pack discipline (geometry + seating quality)

• Spacer thickness tolerance: ±0.002 mm
• Parallelism: ≤0.003 mm
• Flatness: ≤0.003 mm
• Spacer faces were reground before installation to remove prior wear marks and reduce cumulative stack-up error.

2) Rubber ring discipline (preload + damping window)

• Ring material: polyurethane (PU)
• Hardness: 85 Shore A
• Target compression: 0.20–0.30 mm (~6–9%)
• Replacement interval: every 7–9 knife changeovers (earlier if permanent compression exceeded ~15%)

3) Assembly and inspection discipline (verify under load conditions)

• Runout check: dial indicator on knife OD, ~5 mm behind the cutting edge; target max TIR ≤0.012 mm.
• Assembly: arbor cleaned with solvent + lint-free cloth; spacer faces lightly oiled; hydraulic locking nut tightened to machine spec; stack compressed twice before final tightening to reduce seating error.
• First-off validation (every setup): strip width, burr, edge straightness, strip tracking, recoiler stability; production released after three consecutive coils met specs.

Results (after, observed over ~92 operating days / ~11,800 tons)

• Burr height: 18–32 μm → 8–15 μm
• Knife life: +35–45% (1,050–1,300 t → 1,550–1,850 t)
• Unplanned downtime: 5–7 → 2–3 events/month

How it was measured

• Burr: measured on both strip edges every third coil using a 200× digital metallurgical microscope; selected samples cross-checked with a portable surface profilometer.
• なくなる: dial indicator on magnetic base; arbor rotated manually one full revolution; maximum indicator variation recorded as TIR.

Field note (why “in-spec” parts can still fail)

The first implementation did not immediately improve knife life because several older spacers were reused. Although each spacer remained within thickness tolerance, measured face wear of ~0.006–0.010 mm created cumulative irregularity in clamping force. After replacing worn spacers with reground precision spacers and standardizing PU ring compression (~0.25 mm), burr growth became more gradual. Operators also stopped mixing old and new rings within the same stack.

制限事項

These results assumed stable incoming coil flatness, arbor runout below ~0.01 mm, and correct knife overlap settings. If bearings, overlap, or clearance are out of spec, spacer precision alone may not deliver similar gains.

ROI（投資対効果）の試算および測定データ管理

Life extension metrics

“Blade life” is not a single number. Track it as a set of operational metrics:

• tons (or meters) run per grind cycle
• average burr height trend vs run time
• number of unplanned stoppages attributed to edge quality

Where Maxtor Metal’s published tolerance discussions for rotary knives are useful is as a reminder that tight geometry control only pays off when you can show it in your own data. Capture the baseline first, then compare after you tighten spacer and ring discipline.

Scrap and uptime impact

The ROI usually comes from two places:

• scrap/rework reduction (less edge trimming, fewer out-of-tolerance coils)
• uptime (fewer changeovers and less “tuning time” after rebuild)

A simple way to quantify:

• Scrap cost = (scrap tons per month) × (material cost per ton)
• Downtime cost = (unplanned downtime hours) × (line value per hour)
• Tooling impact = (knife + spacer + ring cost) per ton processed

You don’t need perfect accounting—just consistent accounting. If you’re evaluating whether a knife material upgrade is warranted alongside spacer and ring improvements, the rotary slitter knife ROI guide provides a cost-per-ton model that can incorporate both tooling and downtime variables.

Data and maintenance cadence

Set a maintenance cadence that matches your sensitivity:

• rings: inspect every build; replace on a defined interval or when set is visible
• spacer faces: clean every build; re-measure and re-lap/replace when seating damage appears
• runout checks: verify after rebuild and after any abnormal event (jam, crash, strip break)

The goal is simple: keep clearance stable enough that knife wear is predictable.

適正パラメータ範囲および精度検証テンプレート（コピー＆ペースト用）

準拠・整合すべき主要産業規格および試験方法

When you’re trying to make a stack repeatable, the fastest way to eliminate “supplier interpretation” is to align not just on dimensions, but also on how material and hardness are verified.

Below are widely used ISO/ASTM test methods that many quality teams reference for steel tooling components (always match them to your drawing and customer requirements):

• Hardness verification: Rockwell per ISO 6508-1 Rockwell hardness test; microhardness (when needed for case depth or localized checks) per ASTM E384 microindentation hardness testing または ISO 6507-1 Vickers hardness test.
• Mechanical testing reference: for general steel product mechanical testing terminology and methods, many specs point to ASTM A370 mechanical testing of steel products.
• Chemical composition verification: for product check analysis and composition verification practices, many steel purchase specs reference あSTM A751 chemical analysis of steel products.
• Geometric tolerancing language (flatness/parallelism/runout definitions on drawings): use ISO 1101 Geometrical tolerancing to make requirements unambiguous.

Practical tip: if you’re requesting an FAI or dimensional report, specify the test method (ISO/ASTM) alongside the numeric requirement. That turns “we checked it” into evidence you can compare across suppliers.

One reason “clearance under load” is hard to maintain is that teams treat side-clearance, overlap, ring compression, and runout as separate knobs. In practice, they form a window.

Use the templates below to define your own process window (based on your material mix, line speed, and edge-quality requirements). Fill them with your validated numbers—don’t guess.

Template A — Process window (by material and thickness)

Notes to define the window:

• Set the clearance/overlap window from first-off trials and customer edge requirements.
• Set ring compression from repeatability (preload) and thermal stability (avoid permanent set).
• Set the runout limit from what your arbors + stack can hold consistently after rebuild.

Template B — Rebuild checklist + record (per setup)

Template C — Burr trend log (during the run)

FAQs:

Q: ロータリー丸刃スリッターの轴系において、高精度スペーサーは具体的にどのような役割を果たしていますか？

スペーサーは、丸刃相互間の軸方向の幾何学的配置（位置関係）を正確に決定・保持する役割を担っています。スペーサーの厚み公差、平行度、および座面品質が超精密に管理されていれば、通板荷重（カット時の負荷）がかかった状態でも刃先サイドクリアランスが一定に死守され、条（列）ごとの寸法バラつきや偏りを防ぐことができます。

Q: バリの発生原因が、刃先クリアランス（横隙）の不良なのか、それとも丸刃の摩耗によるものなのかを判断する方法は？

すべての条（列）でバリが緩やかに、かつ均一に悪化していく場合は、刃物の摩耗（寿命）の可能性が高くなります。一方で、条ごとにバリの出方がバラバラであったり、刃物の組み替え（リビルド）のたびに状態が変わったり、あるいはバリが「出たり出なかったり」と不安定な場合は、まずはスペーサーの組み込み誤差、ランナウト（総合振れ精度）、または軸系の剛性低下に起因する「動的なクリアランスの変動」を疑うべきです。

Q: スリッター用スペーサーの公差設定は、どのように指定すべきですか？

厚み公差は、製品の仕上がりスリット幅公差および条（列）数に基づいて算出・指定し、組み立ての再現性を確保するために端面の平行度・平面度を厳格に指定してください。図面作成時の規格として、一般寸法公差はISO 2768-1（JIS B 0405相当）に準拠させ、軸穴などの勘合に関わる重要径についてはISO 286-1（JIS B 0401相当）などの寸法公差およびはめ合い方式に従って管理する必要があります。

Q: 駆動・排送用ゴムリング（ストリッパーリング）は、どのようにしてバリの抑制と丸刃の寿命延長に貢献するのですか？

ゴムリングが適正な予圧（プリロード）とダンピング（減衰・衝撃吸収）効果をもたらすことで、動的荷重下における軸系（スタック）の微小なブレや逃げ運動（マイクロムーブメント）を完全に抑え込みます。この安定化作用により、刃先サイドクリアランスの広がりが死守され、刃先コーナー部への不均一な局所荷重が大幅に低減されるため、チッピング（微小崩刃）の進行を劇的に遅らせることができます。

Q: 駆動・排送用ゴムリング（ストリッパーリング）の寿命やへたりを示す兆候にはどのようなものがありますか？

代表的な兆候としては、バリ高さの不安定化、条（列）ごとの切断品質のバラつきの増加、軸系（スタック）周辺へのゴム製品の摩耗粉・ゴミの散乱、そして刃物組み替え（リビルド）後の精度再現性の低下が挙げられます。多くの場合、ゴムの「圧縮永久ひずみ（ヘタリ / Compression set）」や「はみ出し・むしれ（Extrusion）」が原因です。

Q: 超高張力鋼（UHSS）やステンレス鋼（SUS）へ被削材を変更する際、刃先サイドクリアランスの設定も変更すべきですか？

はい、適正クリアランス範囲（プロセスウィンドウ）は材料の引張強度や延性によって大きく異なります。単一の「板厚×〇％」といった万能ルールに依存するのではなく、通板初期の初品検査（First-article checks）や社内で蓄積・文書化した基準データ（ベースライン）に基づいて設定してください。米国の専門誌 The Fabricator によるスリッター加工（slit-in）のトラブル解析でも指摘されている通り、不適切な刃先クリアランスやオーバーラップ（喰い込み量）の設定は、ダイレクトにバリの発生やエッジウェーブ（耳波）などの製品欠陥に直結します。

Q: スペーサーやゴムリングの更新が、実際にROI（投資対効果）の向上につながったかを測定・記録する方法は？

再研磨間通板量（研磨1回あたりの処理トン数：Tons per grind）、バリ高さの経時変化トレンド、製品エッジ品質不良に起因する計画外突発停止回数、および「刃物組み替えから初品検査完了までの時間（Rebuild-to-first-article time）」を追跡・記録してください。その上で、同一の通板鋼板構成（材種バランス）およびライン速度で運用していた過去の基準期間（ベースライン）のデータと比較検証します。

Q: Maxtor Metal製のロールシャー用丸刃（滚剪刀片）は、一般的なスリッターラインの設備仕様与と互換性がありますか？

互換性は、お客様の設備のスリッターシャフト径（アーバーサイズ）、丸刃の外径/内径（OD/ID）、対応板厚範囲、および現在のスタック（刃具組み込み）方式によって異なります。業界用語や寸法公差の迅速な確認リファレンスとして、Maxtor Metalの「ロールシャー用丸刃」の製品ページに一般的なロータリー丸刃スリッターの構成と公差目標値の目安を掲載しております。ご注文の前に、必ずお客様の正確な寸法・形状仕様をご確認ください。

次のステップ（迅速な導入・現場展開手順）

If you want these gains to be repeatable (not a one-time “good run”), treat the spacer pack and rings like calibrated process components.

1. Define your process window: start with one material + thickness; document your acceptable side-clearance and overlap window.
2. Standardize the spacer pack: don’t mix old and new faces; quarantine spacers with seating-face wear; keep a spacer set ID tied to measurement records.
3. Standardize ring compression: choose one ring spec per setup; measure compression (not just “feel”); replace on a defined cadence.
4. Add one measurement that catches drift early: record knife OD runout (TIR) after every rebuild and after abnormal events.
5. Prove ROI with your own data: track tons per grind, burr trend over time, rebuild-to-first-off time, and unplanned stoppages.

If you’d like, Maxtor Metal can review your drawing or sample stack format and recommend a documented inspection plan (what to measure, how often, and how to record it) before you place a production order.

結論

• Key takeaways on spacers, rings, stiffness, and clearance discipline: Stable edge quality comes from holding side-clearance under load. Precision spacers create the rigid geometry; rubber rings provide controlled preload and damping so that geometry doesn’t wander as speed and strip loads rise.
• Next steps: parameter baselines, verification cadence, and continuous improvement: Set a baseline window, measure runout and first-article edge quality every rebuild, and log the results long enough to see real trends. When you treat spacers and rings as calibrated process components—not “hardware in a box”—you can usually turn blade life into something you can forecast.

著者

ジェシー・シュー — Senior Quality Engineer, QA (Quality Assurance), Maxtor Metal

Jesse has 15 years of experience in industrial blade quality engineering, with a particular focus on tolerance stack-up analysis, process capability studies for precision-ground components, and building inspection protocols that connect spacer/ring geometry to downstream edge quality. At Maxtor Metal, he leads incoming and in-process inspection for rotary knife sets, spacers, and related tooling components.

Certifications: ASQ – CQE, ISO 9001 Lead Auditor, ASNT Level II

For readers who want more context on rotary knife terminology, typical clearance ranges by application, and the kind of dimensional control modern knife sets aim for, Maxtor Metal’s reference page on roller shearing blades is a useful starting point.