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ASME B107.15-2002 — Flat Tip Screwdrivers
🪛 ASME B107.15-2002 is the dedicated standard for flat tip (slotted) screwdrivers in the ASME B107 family of standards for hand tools and accessories. It defines general and dimensional data and safety considerations specifically applicable to straight-handle flat tip screwdrivers used for manually driving or removing screws with slotted recesses, and specifies test methods to evaluate performance. Approved as an American National Standard on May 13, 2002, it is a revision of ASME B107.15-1993, Flat Tip and Phillips Screwdrivers; the principal changes were the exclusion of Phillips screwdrivers (now covered by ASME B107.30) and the addition of safety considerations.
💡 A screwdriver is the most common of hand tools, yet deceptively hard to get right: the fit between tip and screw slot governs efficiency and the risk of damage to the screw head and workpiece. B107.15 adds value by quantifying tip geometry and shank strength and verifying them by test.
1. Scope and General Framework 📌
The Standard covers straight-handle flat tip screwdrivers intended for manual operation in driving or removing screws with slotted recesses — the types normally used by cabinetmakers, carpenters, sheet metal workers, production workers, mechanics, and similar trades. Its intent is to specify performance rather than design detail, leaving appearance and construction to the manufacturer so long as size and performance requirements are met.
- Covered: flat tip screwdrivers for slotted screws, including standard-length and stubby variants.
- Excluded: Phillips and other cross-recess screwdrivers (see ASME B107.30).
- Safety: using a screwdriver as a pry bar or striking it with a hammer are clearly misuses; nothing in the Standard condones tool misuse. Proper-use guidance is published in the Hand Tools Institute’s Guide to Hand Tools — Selection, Safety Tips, Proper Use and Care.
⚠️ B107.15 covers manually operated flat tip screwdrivers. For power-driven screwdrivers and bits, refer to the applicable power-tool and bit standards — the dimensional data here should not be applied directly to high-volume power driving.
2. Classification 🔩
Flat tip screwdrivers are classified by handle and blade geometry into two types:
- Type I — Cabinet, Straight Sides: parallel-sided blades used for precision small-screw work such as cabinet hardware. Subdivided into Class 1 (plain), Class 2 (bolster), Class 3 (stubby), and Class 4 (pocket).
- Type II — General Purpose, Flared Sides: blades that flare outward at the sides, offering larger torque capacity for general maintenance and assembly; subdivided into classes by bolster type and handle length.
Figures in the Standard define the nomenclature — blade (shank plus tip), handle, tip, bolster, etc. — providing a common basis for the dimensional tables.
3. Technical Requirements and Specifications 📊
The Standard quantifies screwdriver requirements through dimensional characteristic tables and performance characteristic tables. Tip width and thickness must match the screw slot geometry, and the shank must possess adequate torsional and bending strength. The principal requirements are summarized below:
| Parameter | Typical Specifications | Remarks |
|---|---|---|
| Tip width | 3/16 in, 1/4 in, 5/16 in, 3/8 in series | Matches slotted screw sizes; metric equivalents in mm |
| Tip thickness | Paired with blade size | Ensures engagement depth in the slot, prevents slipping |
| Blade length | 2 in–12 in series (50–300 mm) | Stubby types for confined spaces |
| Hardness | Tip and shank heat-treated to Rockwell (RC) requirements | Verified per ASTM E18 Rockwell hardness test methods |
| Torsional performance | Prescribed torque applied in a standard torsional test block slot | No fracture or permanent tip distortion permitted |
| Bending performance | Bending-moment test, typical setup shown | Verifies shank flexural strength and toughness |
The torsion test uses a torsional test block with a slot machined to the standard cross-section; the screwdriver tip is inserted into the slot and a prescribed torque is applied to verify that the tip does not permanently deform or fracture. The bending-moment test verifies shank strength under mid-span bending. Impact test data tables specify shank behavior under impact blows.
🚨 Dimensional tables do not constitute a list of stock production sizes: the Standard explicitly states that not all products described are available as standard stock. Confirm actual stock sizes with manufacturers before purchasing to avoid buying tips that do not match the screw slots in service.
4. Engineering Practice Essentials 🛠️
- 🔍 Tip-to-slot matching: the tip width should be slightly less than the slot length and the tip thickness should engage near the bottom of the slot for maximum torque transfer with minimal screw-head damage.
- ⚠️ Avoid misuse: never use a screwdriver as a pry bar, chisel, hammer, or drill substitute; discard any screwdriver with a rolled, chipped, or bent tip or a bent shank.
- 🔩 Insulated handles: for work on energized circuits, use dedicated insulated screwdrivers rated for the applicable voltage class; ordinary screwdrivers provide no insulation guarantee.
- 📋 Designations: Section 7 prescribes the product designation format; adopting a uniform designation in purchasing and quality documents improves traceability and spare management.
- 📅 Periodic inspection: include screwdrivers in tool inspection programs — check tip geometry and handle condition and keep tools in good working order.
5. Frequently Asked Questions ❓
❓ Q: Are slotted and Phillips screwdrivers covered by the same standard?
A: No. B107.15-2002 covers only flat tip types; Phillips screwdrivers are now covered by ASME B107.30. Distinguish carefully when purchasing standard documents or making conformance declarations.
A: No. B107.15-2002 covers only flat tip types; Phillips screwdrivers are now covered by ASME B107.30. Distinguish carefully when purchasing standard documents or making conformance declarations.
❓ Q: Can I strike a screwdriver with a hammer to loosen a corroded screw?
A: The Standard does not condone such misuse. Striking bends the shank, chips the tip, and risks the tip slipping from the slot and causing injury. Use penetrants and dedicated impact drivers instead.
A: The Standard does not condone such misuse. Striking bends the shank, chips the tip, and risks the tip slipping from the slot and causing injury. Use penetrants and dedicated impact drivers instead.
❓ Q: How do I judge whether a tip fits its slot?
A: Insert the tip into the slot: an ideal fit has the tip thickness occupying most of the slot depth and the width slightly less than the slot length, with no slip or pop-out under rotation. The tables provide design bases; always verify against the actual slot of the screws in use.
A: Insert the tip into the slot: an ideal fit has the tip thickness occupying most of the slot depth and the width slightly less than the slot length, with no slip or pop-out under rotation. The tables provide design bases; always verify against the actual slot of the screws in use.
🔍 Q: What is the relationship between B107.15 and ISO 2380?
A: ISO 2380 defines cross-recess screwdriver tip geometry within the ISO screwdriver system, while B107.15 is the North American slotted-screwdriver standard. The systems differ; interchangeability must be judged by actual tip geometry rather than by standard family.
A: ISO 2380 defines cross-recess screwdriver tip geometry within the ISO screwdriver system, while B107.15 is the North American slotted-screwdriver standard. The systems differ; interchangeability must be judged by actual tip geometry rather than by standard family.
