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ASME B107.410-2018 — Struck Tools
⚒️ ASME B107.410-2018 is the consolidated standard in the ASME B107 series for struck tools — the hand tools that receive energy from a hammer blow and are themselves struck. Complementing the striking-tool standard (B107.400), struck tools include wood-splitting wedges, wood and glaziers’ chisels, screw extractors, cold chisels and punches, nail sets, brick chisels and star drills, various pry bars, and striking/slugging wrenches. Section 2 provides a cross-reference table (Table 2-1) telling which striking tool should hit each struck tool, preventing mismatched “hammer-on-tool” usage. Section 5 states performance requirements per category, Section 6 the corresponding test methods, and Section 7 the safety requirements and limitations of use.
💡 The struck-tool mode of work creates two chief risks: “mushrooming” and edge spalling of the struck end under repeated hammer blows, and bending or brittle fracture of the shank with flying fragments. B107.410 quantifies both through hardness, chamfer, and a family of impact tests.
1. Tool Categories at a Glance 📌
The Standard organizes tools by Category, subdivided into Type/Class within a category where needed:
| Category | Tool | Typical Use |
|---|---|---|
| 43 | Wood-splitting wedges (square head, stave, Oregon) | Splitting firewood and timber |
| 44 | Glaziers’ chisels, all-steel wood chisels, wood chisels, ripping chisels, flooring/electricians’ chisels | Wood cutting, notching, floor and electrical openings |
| 46 | Multi-spline, spiral-flute, straight-flute, tapered-flute extractors | Removing broken bolts, screws, and taps |
| 48 | Type I chisels, Type II punches, Type III drift pins | Metal cutting, rivet removal, hole alignment |
| 49 | Type I nail set; Type II (self-centering) nail set | Setting nail heads below the wood surface |
| 50 | Brick chisels, brick sets, star drills | Masonry cutting and drilling |
| 52 | Type I struck nail-puller bars, Type II multipurpose/wrecking bars, Type III pry-bar family | Nail pulling, wrecking, opening crates |
| 59 | Striking wrenches, slugging wrenches | Hammer-driven tightening/loosening of heavy fasteners |
2. Performance Requirements: Struck Face, Chamfer, Hardness 🔧
Section 5 lays down shared requirements across categories: the struck face shall be heat-treated to a specified hardness range (Table 5.11-1); the perimeter of the struck face shall carry a chamfer or equivalent radius (Table 5.9-1) proportional to the struck-end size to prevent edge spalling under impact; shanks and cutting edges shall be free of unsafe sharp edges, scratches, and heat-treatment cracks. Each category also defines the cutting-edge geometry (edge angle, bevel) to support its cutting/chiseling function. Table 2-1 specifies which striking tool should be used with each struck tool (e.g., the corresponding hammers of B107.400), avoiding “hammer-on-hammer” mismatches.
⚠️ An over-hardened struck end turns brittle and sheds fragments; an under-hardened one dents and accelerates mushrooming. Sample-check hardness per ASTM E18 Rockwell methods at acceptance, and verify the chamfer is intact.
3. Test Methods 🧪
Section 6 provides complete test sets per category covering fracture, bending, brittleness, pull-out, and prying failure modes:
- Impact Tests: Category 44 chisels, 46 extractors, 48 chisels/punches/drift pins, 52 pry-bar handles, and 59 striking wrenches each have impact parameter tables (6.2.4-1 through 6.2.9.1-1) — repeated blows at prescribed energy verifying the struck end neither cracks nor fails brittly.
- Side Force Test (6.4): lateral-load bending capability of Category 44 chisels.
- Permanent Set Test (6.5.1): residual deformation of chisel edges after blows.
- Bending Moment Test (6.6): bending strength of Category 48 tools.
- Static Force Test (6.7): axial load capacity of Category 48 handled chisels/punches.
- Prying Test (6.9): prying capability of Category 52 bar ends per Table 6.9-1.
- Point End Test (6.10.2): performance of nail-set and similar tips under impact.
💡 The parameter tables (striker mass, blow count, support arrangement) are what make the Standard reproducible. Test reports should cite clause numbers and table numbers item by item, or conformance cannot be judged.
4. Safety Requirements and Limitations of Use 🚧
Section 7 requires: strike each struck tool only with the striking tools the Standard allows; remove mushroomed burrs from the struck end before use (safely, e.g., by grinding behind a guard); wear eye protection per ANSI Z87.1 when working; retire tools with bent shanks, cracks, or chipped edges immediately; and mark products with safety messages per ANSI Z535.4.
🚨 The mushroomed struck end is the number-one injury source: repeated blows upset and flare the end, and an off-center follow-up blow casts fragments at high speed — a clear and present eye hazard. Inspect and dress the mushroom before every use.
5. Engineering Practice Essentials 🛠️
- 🔍 Match the pair: use Table 2-1 to select the striking tool — sledges and long-pattern hammers for heavy work, ball-peen or nail-hammer series for light blows; never beat a large chisel with a small hammer and cause end spalling.
- 🔧 Extractor technique: for Category 46 extractors, drill first, then drive the extractor counter-rotation with an impact wrench or tap wrench; avoid torque overload that breaks the extractor itself.
- 📊 Edge care: regrind chisels to the standard edge angle and keep them sharp; never “free-hand grind” in a way that anneals and softens the edge.
- 📋 Procurement and acceptance: request B107.410 test reports (impact, bending, prying) and hardness data; verify the category/type marking.
6. Frequently Asked Questions ❓
❓ Q: How do B107.410 and B107.400 relate?
A: They are companion standards: B107.410 covers struck tools (chisels, punches, wedges, pry bars), B107.400 covers striking tools (hammers of all kinds); correct use pairs them per Table 2-1.
A: They are companion standards: B107.410 covers struck tools (chisels, punches, wedges, pry bars), B107.400 covers striking tools (hammers of all kinds); correct use pairs them per Table 2-1.
🔍 Q: Why must the struck end of a cold chisel be chamfered?
A: The chamfer or equivalent radius markedly reduces the probability of edge spalling; an unchamfered struck end produces sharp fragments and high-speed chips on off-center blows.
A: The chamfer or equivalent radius markedly reduces the probability of edge spalling; an unchamfered struck end produces sharp fragments and high-speed chips on off-center blows.
❓ Q: Which category do screw extractors belong to, and are they struck?
A: Category 46; they work by being screwed in and are generally not hammered. Their “struck” character is weak, yet the Standard still specifies impact test parameters to cover limit conditions.
A: Category 46; they work by being screwed in and are generally not hammered. Their “struck” character is weak, yet the Standard still specifies impact test parameters to cover limit conditions.
❓ Q: Are pry bars (Category 52) really “struck tools”?
A: Yes. Type I nail-puller bars are designed to be struck; Type II/III bars are mostly nonstruck, but the whole family belongs to the struck-tool umbrella and its prying ends must pass the prying and point-end tests.
A: Yes. Type I nail-puller bars are designed to be struck; Type II/III bars are mostly nonstruck, but the whole family belongs to the struck-tool umbrella and its prying ends must pass the prying and point-end tests.
