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ASME B107.30-2002 — Cross Tip Screwdrivers
🔩 ASME B107.30-2002 is a substandard of the ASME B107 family, Hand Tools and Accessories, that defines the classification, dimensions, performance, and safety requirements for straight-handle cross tip screwdrivers intended for manual driving or removal of screws with PHILLIPS® (PH) or POZIDRIV® (PZ) recesses. It complements other B107 documents such as B107.31M (cross tip screwdriver gaging) and is widely referenced by cabinetmakers, carpenters, sheet metal workers, production workers, and mechanics.
💡 The Standard specifies performance rather than design detail: as long as a product meets the defined functional, dimensional, and test requirements, manufacturers are free to use their own internal construction and processes, leaving room for product innovation.
1. Scope and General Principles 📌
The Standard covers straight-handle screwdrivers of both Phillips (PH) and Pozidriv (PZ) design, used for driving or removing screws with matching recesses in cabinetmaking, carpentry, sheet metal work, production assembly, and mechanical repair. Two principles are stated explicitly:
- Performance orientation: the purpose is to define performance requirements rather than to constrain design details, provided the requirements are met.
- Not a stock list: inclusion of dimensional data does not imply that all products are stock production sizes; consumers should consult manufacturers about available stock sizes.
The scope also warns clearly: using a screwdriver as a pry bar or striking it with a hammer are misuses of the tool, and nothing in the Standard condones such misuse.
⚠️ Always apply torque along the screw axis and keep the tip centered. A cross tip screwdriver is designed to transmit torque — never as a pry, chisel, or striking tool, or you risk damaging the tip and injuring yourself or the workpiece.
2. Types and Classification 🔧
The Standard defines two types, each subdivided into four classes:
- Type I — Phillips (PH): for PHILLIPS recesses, with four standard main flutes.
- Type II — Pozidriv (PZ): for POZIDRIV recesses, which add secondary flutes between the main flutes; the profile differs from PH.
Common class designations for both types: Class 1 plain, Class 2 bolster, Class 3 stubby, and Class 4 pocket. Each class addresses a different grip and use scenario — the bolster adds a shoulder to limit insertion depth, while the stubby and pocket designs suit confined spaces and portability.
| Type | Typical Tip Sizes | Classes | Construction Feature | Typical Use |
|---|---|---|---|---|
| Type I (PH) | PH #0–#4 | Class 1–4 | Four-flute cross head | General woodworking, assembly, everyday repair |
| Type II (PZ) | PZ #0–#3 | Class 1–4 | Main plus secondary flutes | European appliances and furniture with PZ screws |
| Class 2 bolster | — | — | Shoulder on shank | Precision assembly requiring limited insertion |
| Class 3 stubby | — | — | Short shank, small torque arm | Tight spaces and work close to surfaces |
| Class 4 pocket | — | — | Compact, easy to carry | Portable kits, instruments and eyewear repair |
3. Tip Dimensions and Performance Requirements 📏
The Standard tabulates key tip geometry for each size — major wing spread, minor wing spread, and point diameter — with a dimensional tolerance of ±0.002 in. (about ±0.05 mm). These dimensions govern how well the tip seats in the screw recess, directly affecting torque transfer efficiency and resistance to cam-out.
💡 The tables also specify minimum torsional test values (in in·lbf): with the tip engaged in a calibrated test block, applied torque must not cause visible permanent deformation or fracture. Minimum blade, assembly, and overall lengths are defined as well.
Material chemistry and heat treatment must be such that the finished tool meets the performance and safety requirements defined in the Standard; tip hardness is verified by Rockwell hardness testing so the edge stays sharp without chipping under repeated use.
4. Test Procedures 🔬
Section 6 defines the test procedures used for conformance verification:
- Dimensional inspection: measurement of wing spread, point diameter, and blade length with gages under specified conditions.
- Torsional test: the tip is engaged in a test block of defined wing spread and loaded to the required torque to check deformation and damage.
- Hardness test: Rockwell hardness verification of the heat-treated tip.
Test results establish whether the product meets the specified performance grade and support the manufacturer’s outgoing quality control.
5. Engineering Practice and Safety 🛠️
- 🔍 Selection: first identify whether the screw recess is PH or PZ, then match the tip size (#0–#4) to the screw head diameter; mixing a PH tip with a PZ screw causes poor fit, slippage, and damaged recesses.
- 🔧 Tip fit: the tip should seat fully and remain centered, applying force perpendicular to the screw axis; if the tip slips out frequently, check whether the size is too small or the edge is worn.
- 📊 Torque control: cross recesses are designed to “cam out” and protect the screw on overload — never slip a wrench over the shank to gain extra leverage, which damages the tip or recess.
- 📋 Care and storage: clean the tip after use, apply a thin rust-preventive film, and store separately to avoid edge contact; bolster and cushion-grip versions improve comfort in prolonged work.
🚨 Never use a cross tip screwdriver for prying, chiseling, or hammering. The Standard states plainly that such uses are misuse. When working near live electrical equipment, also follow electrical safety rules to prevent electric shock.
6. Frequently Asked Questions ❓
❓ Q: What is the difference between PH and PZ?
A: Phillips (PH) is the classic cross recess; Pozidriv (PZ) adds four 45° secondary flutes between the main flutes for a tighter bite and better cam-out resistance. The two must not be interchanged — always match the driver to the recess.
A: Phillips (PH) is the classic cross recess; Pozidriv (PZ) adds four 45° secondary flutes between the main flutes for a tighter bite and better cam-out resistance. The two must not be interchanged — always match the driver to the recess.
❓ Q: How do I tell whether to use a PH or PZ tip?
A: Inspect the screw head: a PZ recess shows short secondary flutes between the main wings and a flatter bottom, while a PH recess tapers to a point. If the tip feels loose in the slot, it is the wrong match.
A: Inspect the screw head: a PZ recess shows short secondary flutes between the main wings and a flatter bottom, while a PH recess tapers to a point. If the tip feels loose in the slot, it is the wrong match.
❓ Q: Why are the tolerances expressed in inches?
A: The B107 series grew from the U.S. customary system for North American tool makers; metric export products must apply the equivalent conversion so that fit is preserved, and the unit system used should be stated in procurement documents.
A: The B107 series grew from the U.S. customary system for North American tool makers; metric export products must apply the equivalent conversion so that fit is preserved, and the unit system used should be stated in procurement documents.
🔍 Q: What marking is required on the product?
A: The manufacturer should mark its name or trademark and size designation (e.g., PH2 or PZ1) for traceability, and provide the full designation in orders and packaging so buyers can accept product to B107.30.
A: The manufacturer should mark its name or trademark and size designation (e.g., PH2 or PZ1) for traceability, and provide the full designation in orders and packaging so buyers can accept product to B107.30.
