ScissorPedia

Two-Piece Welding (二枚合わせ構造)

Manufacturing processes
Process-evidence instrument

Follow a process claim from step to finished-tool scope

General metallurgy and a named factory claim are different evidence layers; preserve the material, step, actor, and exact product. Apply to Two-Piece Welding (二枚合わせ構造)
PROCESS ≠ OUTCOME
Process name Material + step Factory evidence Finished-tool scope
  1. 01 Define Use the process term precisely and distinguish adjacent methods.
  2. 02 Place the step Record input material, sequence position, controls, and stated purpose.
  3. 03 Verify the actor Separate general process context from named factory documentation.
  4. 04 Bound the claim Attach any property or origin statement to the exact finished product.

Do not inferA forge, spark, hammer, heat, workshop, or process name cannot prove a scissor factory, alloy, temperature, grain flow, quality, or result.

Joined-construction lane

Map each component before interpreting a welded build

A joined construction can combine different parts and production routes. The joint alone does not establish either material or performance.

Record Verify Open Act next

  1. Construction claim

    Name every part

    Record the exact terms for blade, handle, shank, tang, joint, and any claimed materials.

  2. Responsible source

    Check the source

    Use the maker or named production source that can identify how this model's components are made and joined.

  3. Assembly record

    Record or unknown

    Seek a drawing, bill of materials, process sheet, or written confirmation of component boundaries and joint method.

  4. Exact-model match

    Match exact scope

    Match code, size, handedness, period, and market; a construction used elsewhere in a range is not this model's record.

  5. Next verification action

    Ask parts + service

    Ask the maker which parts are joined, what each part is, and which repair or service route applies.

Evidence boundary: A visible line, finish change, magnet response, or marketing cutaway does not prove materials, joint method, or service life.

If records conflict: keep each source, date, market, and scope attached. Do not average the claims or choose by appearance; leave the result open and ask the responsible source to resolve it.

Description

Two-piece welding joins a forged blade to a cast handle for the best of both worlds. Learn how this hybrid construction balances cutting performance with ergonomic design.

Two-Piece Welding (二枚合わせ構造 / nimai-awase kōzō)

Quick look

  • Process: Blade forged from ultra-hard steel, handle formed from a tougher or lighter material, then the two pieces are welded together.
  • Key benefit: Each component uses the optimal alloy for its function — maximum hardness at the edge, maximum toughness at the handle.
  • Cost position: Premium. Requires two separate forming operations plus precision welding and post-weld heat treatment.
  • Where used: High-end Japanese manufacturers pushing hardness limits (HRC 64+), specialty German makers, performance-oriented brands.

Why it matters

Every scissor steel involves a compromise between hardness and toughness. Harder steel holds a sharper edge longer but becomes brittle; tougher steel absorbs shock but dulls faster. A one-piece scissor must live at a single point on that spectrum.

Two-piece welding breaks the compromise. The blade portion can be forged from an extremely hard alloy — sometimes reaching HRC 64-67 — while the handle, shank, and finger rings are made from a softer, more shock-absorbent material. The weld joint bonds them permanently, and the stylist gets the best of both worlds: an edge that stays razor-sharp for months and a handle that will not snap if the scissor is dropped.

The Hayashi HYS-MAX67 example

One of the clearest demonstrations of this technique is the Hayashi HYS-MAX67. The blade portion is hardened to HRC 67 — far beyond what any single-piece scissor steel can safely sustain — while the base material provides the structural toughness needed for daily salon use. The weld zone is carefully heat-treated so it does not become a stress riser.

How it works

  1. Blade forging: The cutting blade is forged or ground from a high-hardness steel (high-carbon, powder metallurgy, or cobalt alloy).
  2. Handle forming: The handle section is forged, stamped, or cast from a tougher stainless steel or titanium alloy.
  3. Joint preparation: Mating surfaces are precision-machined for flush contact.
  4. Welding: Friction welding, electron beam welding, or laser welding joins the two pieces. The method depends on the alloys involved — dissimilar metals often require solid-state (friction) welding to avoid brittle intermetallic compounds.
  5. Post-weld heat treatment: The joint zone is stress-relieved and tempered so the heat-affected zone does not become a weak point.
  6. Grinding and finishing: The weld line is ground flush and the scissor proceeds through normal finishing, so the joint is invisible in the final product.

Trade-offs

  • Pros: Unlocks extreme blade hardness without sacrificing handle toughness, lighter overall weight possible (titanium handles), enables material combinations impossible in one-piece construction.
  • Cons: Higher manufacturing cost, weld integrity is a critical quality point, requires precise post-weld heat treatment, not all sharpeners understand the transition zone.

What to ask a manufacturer

If a brand advertises hardness above HRC 62-63, it is very likely using a two-piece or composite construction. Ask where the weld joint is located, what alloy is used for each section, and whether the joint zone has been independently tested for fatigue. A visible weld line is not a defect — it is a feature of the engineering.

See Also

Best shears for beginners →

Source trail

Sources Reviewed

1 scoped source behind this entry
  1. Secondary Nakanishi Special Site — Hayashi Scissors Interview (manufacturer interview)

Source scope and limitations are stated on the page. External links open in new tabs.

Quick clarifications

Frequently Asked Questions

3 answers you can open one at a time
Why use two-piece welding instead of a single-piece scissor?

Every scissor steel forces a compromise between hardness and toughness — harder steel holds an edge longer but becomes brittle, tougher steel absorbs shock but dulls faster. A one-piece scissor must live at a single point on that spectrum. Two-piece welding breaks the compromise by letting the blade portion be forged from an extremely hard alloy — sometimes HRC 64 to 67 — while the handle, shank, and finger rings use a softer, more shock-absorbent material.

What welding methods join dissimilar scissor alloys?

Friction welding, electron beam welding, or laser welding depending on the alloys involved. Dissimilar metals often require solid-state friction welding to avoid brittle intermetallic compounds forming in the joint. After welding, the joint zone is stress-relieved and tempered separately so the heat-affected zone does not become a stress riser, then the weld line is ground flush during normal finishing — which is why the joint is usually invisible in the final product.

Is a visible weld line on a scissor a defect?

No — it is the feature that enables extreme blade hardness. If a brand advertises hardness above HRC 62 or 63, the scissor is very likely using two-piece or composite construction. The Hayashi HYS-MAX67 is a clear example: blade hardness at HRC 67, far beyond what any single-piece scissor steel can sustain without brittleness, paired with a tougher base material for daily handling. Ask where the weld joint sits, what alloy each section uses, and whether the joint has been tested for fatigue.

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Last updated: July 27, 2026 · by
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