How Professional Scissors Are Made: The 15-Stage Manufacturing Process
From steel rod to finished shears in 15 stages. A plain English walkthrough of forging, heat treatment, grinding, assembly, and quality testing.
What happens before scissors reach your hand
A premium pair of professional shears goes through 30 to 90 individual steps between raw steel and your holster. Mass-produced models require fewer steps; handmade competition shears require more. But every pair follows the same general path.
This guide covers the 15 core stages of professional scissor manufacturing (製造工程, seizō kōtei). Understanding the process helps you evaluate quality claims from manufacturers and appreciate why certain shears cost what they do.
Stage 1: Design (設計, sekkei)
Modern scissors start as digital models. Manufacturers use 3D CAD software to design blade geometry, handle ergonomics, and balance points. Some companies run computer simulations that predict stress on hand muscles and tendons during cutting motions. The design stage determines blade curvature, edge angle, handle offset, and weight distribution before any metal is touched.
Stage 2: Material preparation (材料準備)
Steel rod or sheet stock arrives from steelmakers. The manufacturer inspects it for composition, grain structure, and defects. For dual-material scissors (where the blade edge and handle are made from different steels), separate materials are prepared for each component. The grade of steel chosen at this stage sets the ceiling for how sharp, durable, and corrosion-resistant the finished shears can be.
Stage 3: Forging or casting (鍛造 / 鋳造)
Two methods shape the raw steel into rough scissor blanks.
Forging (鍛造, tanzō) presses steel into shape using heavy dies. Hot or cold forging compacts the grain structure, producing denser material with fewer internal defects. Forging is preferred for blade edges because it creates superior toughness.
Casting (鋳造, chūzō) pours molten metal into molds. It allows more complex shapes, making it useful for ergonomic handles. Cast material can contain porosity and inclusions, so it is not ideal for cutting edges.
The best approach combines both. Forge the blade, cast the handle, then join them. This costs significantly more than single-material construction, but it puts the right material in the right place.
Stage 4: Welding and joining (溶接, yōsetsu)
For dual-material scissors, the forged blade blank is welded to the cast handle blank. This creates a single piece called the welded blank (溶接ブランク), combining optimized edge steel with a handle material chosen for comfort and weight.
Stage 5: Rough grinding (荒研ぎ, aratogi)
The blank goes to grinding wheels where excess material is removed. This stage establishes the basic blade geometry, blade width, and overall profile. Think of it as roughing out the shape from a block of marble. Precision is not the goal yet. Getting close to the final shape is.
Stage 6: Heat treatment (熱処理, netsushori)
This is where steel becomes a cutting tool. Heat treatment happens after rough shaping but before final grinding.
Hardening: The blade is heated to between 1050°C and 1100°C (about 1920°F to 2010°F), then rapidly cooled (quenched). This transforms the steel’s crystal structure, making it extremely hard. Without this step, the steel would be too soft to hold an edge.
Tempering: The hardened steel is then reheated to a lower temperature to reduce brittleness. Hardness without toughness means a blade that chips on first contact with a comb. Tempering finds the balance.
Sub-zero treatment (サブゼロ処理): Some manufacturers take the heat-treated blade down to extreme cold, anywhere from minus 70°C to minus 196°C (liquid nitrogen temperatures). This converts remaining soft steel structures into hard martensite, improving edge retention and blade consistency. Jaguar’s Friodur process and several Japanese manufacturers use variations of this technique.
Stage 7: Straightening and alignment (矯正, kyōsei)
Heat treatment warps blades slightly. Skilled technicians straighten them by hand, checking for alignment that will affect how the two blades interact for the entire life of the scissors. This is not a step that machines handle well. It requires experience and touch.
Stage 8: Fine grinding (仕上げ研削, shiage kensaku)
Precision grinding on progressively finer wheels establishes the exact blade edge geometry. This stage creates the hollow (concave) inner surface and the convex outer surface. The grinder also shapes the ride, which is the contact area where the two blades meet near the pivot. The quality of fine grinding determines how cleanly the scissors will cut and how long they will hold that performance.
Stage 9: Drilling and screw fitting (穴あけ・ネジ取付)
The pivot hole is drilled with extreme precision. How concentric and true this hole is determines cutting accuracy for the life of the shears. The screw or pivot system is then fitted. Even a tiny deviation here compounds into blade misalignment over thousands of opening and closing cycles.
Stage 10: Handle shaping and finishing (ハンドル成形・仕上げ)
The handle reaches its final form through grinding, polishing, or CNC machining. Finger holes are sized and smoothed. The finger rest (小指掛け, kobikake) is attached or shaped. Bumpers and silencers (ストッパー, sutoppā) are installed between the shanks.
Stage 11: Assembly (組立, kumitate)
The two blades are joined at the pivot with the screw system. Tension is set to factory specification. The technician checks the ride and adjusts how the blades interact. Then the opening and closing action is tested repeately. If the blades do not glide smoothly at this stage, the scissors go back for rework.
Stage 12: Sharpening (研ぎ, togi)
The most critical stage. Multiple approaches exist, but one tradition stands out.
Hamaguri convex sharpening (蛤刃研ぎ, hamaguriba togi) builds a gently convex blade face through as many as seven different grinding angles. A master sharpener (研ぎ師, togishi) works by hand on water-cooled stones, applying varying pressure across the blade surface. This creates a convex edge that is more durable than a flat grind because more steel supports the cutting edge.
This technique connects directly to Japanese swordmaking. It cannot be fully automated. A sharpener may spend years mastering just this one stage.
Convex edge (コンベックスエッジ) finishing produces blades where the outer surface is rounded outward and the inner surface is hollow ground. The blades only touch at the exact point of cutting, reducing resistance and hand fatigue.
Flat blade (片刃, kataba) sharpening is simpler and produces a lightweight blade suitable for a wide range of techniques. This is the world standard for general-purpose scissors.
Stage 13: Polishing (磨き, migaki)
The surface receives its final finish: mirror, satin, matte, or a decorative pattern. If the scissors will have a titanium or DLC (Diamond-Like Carbon) coating, it is applied at this stage.
Stage 14: Quality inspection (品質検査, hinshitsu kensa)
Each scissor is inspected for blade alignment and ride, cutting performance on test hair or tissue, handle smoothness and ring sizing, screw tension and smoothness, and visual finish quality. Serial numbers are engraved. Defective units are rejected or sent back for rework. At quality-focused manufacturers, this stage is not a formality. It is where a meaningful percentage of production gets pulled.
Stage 15: Packaging and shipping (包装・出荷)
Scissors are oiled for protection and packaged with accessories: chamois leather, oil, adjustment key, finger inserts, a case, warranty card, and serial number documentation.
Why this matters to you
Understanding these stages changes how you evaluate a purchase.
Heat treatment is invisible but critical. Two scissors made from the same steel grade can perform very differently if one received proper heat treatment and sub-zero processing and the other did not. You cannot see this difference by looking at the scissors.
The sharpening method matters for the life of the tool. If your shears were finished with hamaguri technique, they need to be resharpened the same way. Sending them to a sharpener who uses European belt grinding (Konvex-Schliff) will permanently alter the blade geometry.
Assembly and adjustment quality separate tiers. The steps from Stage 9 through Stage 12 are where the real difference between a $200 shear and an $800 shear often lives. Cheaper scissors may use the same steel but spend less time on fitting, alignment, and hand finishing.
Ask manufacturers which stages they control. In Seki City’s bungyosei (分業制) system, different specialists handle different stages. A brand that controls sharpening and assembly but outsources forging is telling you something about where they invest their expertise. Neither approach is automatically better, but knowing the answer helps you compare.