{"product_id":"l-shape-90-degree-knife-edge-square-ruler-grade-1-stainless-steel","title":"90° Knife Edge Square Ruler – Grade 1 Stainless Steel, 4 Sizes","description":"\n\u003ch2\u003ePrecision 90° Knife Edge Square Ruler – Professional Grade 1 Accuracy\u003c\/h2\u003e\n\u003cp\u003eAchieve flawless right-angle measurements every time with this \u003cstrong\u003eL-Shape Knife Edge Square Ruler\u003c\/strong\u003e. Crafted from high-quality stainless steel and ground to \u003cstrong\u003eGrade 1 accuracy\u003c\/strong\u003e, this angle square is an essential tool for machinists, woodworkers, engineers, and craftspeople who demand precise layout and measurement work.\u003c\/p\u003e\n\n\u003ch3\u003eKey Specifications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Stainless Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAvailable Sizes:\u003c\/strong\u003e 63×40 mm | 80×50 mm | 100×63 mm | 125×80 mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEdge Angle:\u003c\/strong\u003e 30° Knife Edge (bevelled on both sides)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeat Width:\u003c\/strong\u003e 5 mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAccuracy:\u003c\/strong\u003e Grade 1\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSquareness Tolerance:\u003c\/strong\u003e 0.02–0.05 mm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCountry of Origin:\u003c\/strong\u003e Made in China\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Choose This Knife Edge Square?\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e✅ \u003cstrong\u003eLight-Gap Method Compatible:\u003c\/strong\u003e The double-bevelled 30° knife edge blade makes it perfect for checking squareness using the light-gap method — spot even the tiniest deviation instantly.\u003c\/li\u003e\n  \u003cli\u003e✅ \u003cstrong\u003eGround \u0026amp; Lapped for Parallelism:\u003c\/strong\u003e Both beams and blades are precision-ground and lapped, ensuring consistent, repeatable measurements across every use.\u003c\/li\u003e\n  \u003cli\u003e✅ \u003cstrong\u003eGrade 1 Precision:\u003c\/strong\u003e With a squareness tolerance of just 0.02–0.05 mm, this ruler meets the demands of professional-level layout and inspection work.\u003c\/li\u003e\n  \u003cli\u003e✅ \u003cstrong\u003eProtective Case Included:\u003c\/strong\u003e Each ruler ships in a dedicated protective case to preserve the precision edges and keep the tool in perfect condition between uses.\u003c\/li\u003e\n  \u003cli\u003e✅ \u003cstrong\u003eMultiple Size Options:\u003c\/strong\u003e Choose the size that best fits your workpiece — from compact 63×40 mm up to the larger 125×80 mm format.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eIdeal Applications\u003c\/h3\u003e\n\u003cp\u003eThis knife edge square ruler is designed for \u003cstrong\u003eprecision layout, squareness checking, and measurement verification\u003c\/strong\u003e across a wide range of industries and hobbies, including:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eMachining \u0026amp; metalworking\u003c\/li\u003e\n  \u003cli\u003eWoodworking \u0026amp; cabinetmaking\u003c\/li\u003e\n  \u003cli\u003eEngineering \u0026amp; quality control inspection\u003c\/li\u003e\n  \u003cli\u003eTool \u0026amp; die making\u003c\/li\u003e\n  \u003cli\u003eDIY precision projects\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat's in the Box?\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × L-Shape Knife Edge Square Ruler\u003c\/li\u003e\n  \u003cli\u003e1 × Protective Case\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eYou May Also Like\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-precision-japanese-double-edged-hand-saw-sk5-steel-fine-toothed-for-carpentry-and-gardening-6-inch-blade-portable-mini-1\"\u003e1pc Precision Japanese Double-Edged Hand Saw – SK5 Steel, Fine-Toothed for Carpentry and Gardening\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/10pcs-wooden-handle-nylon-bristle-paint-brush-for-oil-painting-dusting-and-cleaning-unrechargeable-hand-tool-set-without-batt-2\"\u003e10Pcs Wooden Handle Nylon Bristle Paint Brush Set for Oil Painting, Dusting and Cleaning\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/1pc-professional-heavy-duty-pruning-shears-with-anti-slip-handle-design-suitable-for-trimming-thick-and-sturdy-branches\"\u003e1pc Professional Heavy-Duty Pruning Shears with Anti-Slip Handle Design\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.osha.gov\/personal-protective-equipment\" target=\"_blank\" rel=\"noopener\"\u003eOSHA on personal protective equipment\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What sizes does the L-Shape Knife Edge Square Ruler come in?\u003c\/h4\u003e\n\u003cp\u003eA: The ruler is available in four sizes: 63×40 mm, 80×50 mm, 100×63 mm, and 125×80 mm, so you can choose the right format for your specific measurement or layout task.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What does \"Grade 1 accuracy\" mean for this square ruler?\u003c\/h4\u003e\n\u003cp\u003eA: Grade 1 is a professional precision classification. It means the squareness tolerance of this knife edge square is just 0.02–0.05 mm, making it suitable for demanding machining, engineering, and inspection applications where tight tolerances are essential.\u003c\/p\u003e\n\n\u003ch4\u003eQ: How is the knife edge square used to check squareness?\u003c\/h4\u003e\n\u003cp\u003eA: Place the beam (stock) flat against a reference surface and bring the 30° knife-edge blade against the workpiece edge. Hold the assembly up to a light source — any visible light gap between the blade and the workpiece reveals deviation from true 90°. This is known as the light-gap method and is a standard technique in precision measurement.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Does this ruler come with any protective storage?\u003c\/h4\u003e\n\u003cp\u003eA: Yes. Each L-Shape Knife Edge Square Ruler is supplied with a dedicated protective case to safeguard the precision-ground edges and ensure the tool stays accurate over its lifetime.\u003c\/p\u003e\n\u003c!-- production-packaging-notice --\u003e\n\u003ch3\u003eProduction \u0026amp; Packaging Notice\u003c\/h3\u003e\n\u003cp\u003eTo maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What sizes does the L-Shape Knife Edge Square Ruler come in?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The ruler is available in four sizes: 63×40 mm, 80×50 mm, 100×63 mm, and 125×80 mm, so you can choose the right format for your specific measurement or layout task.\"}}, {\"@type\": \"Question\", \"name\": \"What does \\\"Grade 1 accuracy\\\" mean for this square ruler?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Grade 1 is a professional precision classification. 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