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ASME B107.600-2016 — Screwdrivers and Screwdriver Bits
🪛 ASME B107.600-2016 is the consolidated ASME B107 family standard for hand screwdrivers and screwdriver bits. It defines dimensional, performance, and safety requirements for the three major tip families — Flat, Phillips (PH), and Pozidriv (PZ) — together with gaging and test methods and limitations of safe use. Issued on August 12, 2016, and effective one year later, it revises the 2008 edition and supersedes four earlier component standards: B107.15 (Flat Tip Screwdrivers), B107.26 (Screwdriver Bits, Hand Driven), B107.30 (Cross Tip Screwdrivers), and B107.31 (Screwdrivers, Cross Tip Gaging).
💡 Since 1999 ASME has consolidated hand-tool standards by category; B107.600 is one outcome of that project — merging separate style-based standards into a single three-digit document for easier use and procurement.
1. Scope and Overview 📌
The Standard defines dimensional, performance, and safety requirements for screwdrivers and screwdriver bits, and specifies the test and gaging methods used to evaluate conformance, plus limitations of safe use. Its coverage includes:
- Flat tips: the traditional straight blade, sized by blade width, thickness, and shank geometry.
- Phillips (PH) tips: tapered cross-recess tips from PH-0 through PH-4, verified with ring gages and master plug gages.
- Pozidriv (PZ) tips: cross-recess tips with additional small wings for better centering and anti-slip performance.
The Standard quantifies every tip through dimensional and performance tables (Tables 1–4) and a family of dedicated gages (Style A ring gages, Style B GO/NO GO ring penetration gages, master plug gages), with subclassifications, options, and designation rules in Nonmandatory Appendix A.
⚠️ PH and PZ recesses look similar but are geometrically different: PH flanks are tapered, while PZ flanks are nearly parallel with four auxiliary wings. Inserting a PH bit into a PZ screw (or vice versa) gives poor engagement, slipping, and damage — always distinguish the two.
2. Technical Requirements and Specifications 📏
The heart of the Standard is the dimensional and performance tables for the three tip families. Key parameters are summarized below:
| Tip Type | Size Series | Primary Gages | Key Performance Items |
|---|---|---|---|
| Flat | Multiple by blade width/thickness | Flat-tip test blocks | Blade width, thickness, bending moment |
| Phillips PH | PH-0 / PH-1 / PH-2 / PH-3 / PH-4 | Style A ring gage, master plug gage, Style B GO/NO GO ring gage | Tip penetration, wing spread, bending moment |
| Pozidriv PZ | Series per Standard | PZ ring gage, PZ master plug gage, GO/NO GO ring gage | Dimensions, penetration, wing spread |
Test methods include the bending moment test (typical setup per Fig. 7, verifying shank and blade strength), the impact test (per Table 5 impact data), and penetration gaging (Style A/Style B ring gages and master plug gages verifying engagement with the screw recess). Designation and marking follow the subclassification and option rules of Nonmandatory Appendix A.
💡 GO/NO GO gaging is the essence of conformance: the GO end must pass, the NO GO end must be positively stopped — a quantitative guarantee of interchangeability and fit quality between bit and recess.
3. Test Methods and Quality Control 🔬
- Dimensional and geometric checks: ring gages, master plug gages, and test blocks measure blade width, thickness, wing spread, tip geometry, and penetration depth.
- Bending moment test: the specified moment is applied on the typical test apparatus; no service-affecting permanent deformation or fracture is permitted.
- Impact test: per Table 5, verifying crack resistance of bits under impact-style service.
- Traceability: materials must be sufficiently tough and marking clear.
🚨 Safety (Section 7): screwdrivers are for hand turning only — never hammer the handle, and never use the bit as a chisel or pry bar; replace worn, chipped, or bent tools immediately to avoid slip injuries.
4. Engineering Practice Essentials 🛠️
- 🔍 Selection: identify the recess type (Flat / PH / PZ) and size first, then choose the matching bit; never mix PH and PZ; match bit size to screw size — oversized or undersized bits damage the recess.
- 🔧 Technique: seat the bit perpendicular and fully into the recess, apply axial pressure before turning, and avoid radial wobble that causes slip-out.
- 📊 Torque matching: for high torque or fastening in awkward positions, prefer magnetic or locating bits; choose impact-rated bits for power tools.
- 📋 Verification: use the Standard’s gages for receiving inspection and confirm supplier conformance with the dimensional tables.
In practice, the correct tip size is just as important as the correct recess type. A PH-2 screw should be driven with a PH-2 bit — a PH-1 bit engages only the outer portion of the recess and will cam out under load, while a PH-3 bit cannot seat deeply enough. The same principle applies to PZ recesses. When assembling sets or kitting out workstations, organize bits by type and size, and periodically regrind flat tips or replace worn cross tips rather than struggling with damaged heads. Careful bit selection reduces fastener damage, improves torque delivery, and lowers the risk of slipping injuries, all of which the Standard’s dimensional and gaging system is designed to support.
5. Frequently Asked Questions ❓
❓ Q: PH and PZ bits look alike — can they be interchanged?
A: No. The recess geometries differ (PH tapered, PZ parallel-sided with wings); mixing causes poor engagement, slipping, and damage to both bit and screw — one of the most common field errors.
A: No. The recess geometries differ (PH tapered, PZ parallel-sided with wings); mixing causes poor engagement, slipping, and damage to both bit and screw — one of the most common field errors.
❓ Q: Which standards did B107.600 supersede?
A: B107.600-2008 superseded and rendered obsolete B107.15 (flat tip screwdrivers), B107.26 (hand-driven screwdriver bits), B107.30 (cross tip screwdrivers), and B107.31 (cross tip gaging); the 2016 edition revises it.
A: B107.600-2008 superseded and rendered obsolete B107.15 (flat tip screwdrivers), B107.26 (hand-driven screwdriver bits), B107.30 (cross tip screwdrivers), and B107.31 (cross tip gaging); the 2016 edition revises it.
🔍 Q: What is “penetration” gaging?
A: Penetration is the maximum depth the bit enters the screw recess; it is verified with dedicated penetration gages (Style B GO/NO GO ring gages and master plug gages) and determines actual engagement and torque transfer.
A: Penetration is the maximum depth the bit enters the screw recess; it is verified with dedicated penetration gages (Style B GO/NO GO ring gages and master plug gages) and determines actual engagement and torque transfer.
🔧 Q: Can a bit be used as a chisel or pry bar?
A: No. The Standard limits screwdrivers to rotary driving; using bits as chisels, pry bars, or impact tools quickly ruins the tip and creates spalling and debris hazards.
A: No. The Standard limits screwdrivers to rotary driving; using bits as chisels, pry bars, or impact tools quickly ruins the tip and creates spalling and debris hazards.
📋 Q: What should a quality program check on incoming screwdrivers?
A: Confirm tip type and size against the Standard’s tables, verify PH and PZ tips with the master plug and ring gages, spot-check flat tips on the test blocks, and record bending-moment and impact results for each lot. Store bits so tips are protected, reorder by exact designation, and remove any tool whose tip has rounded, chipped, or bent from the crib before it can damage a production fastener.
A: Confirm tip type and size against the Standard’s tables, verify PH and PZ tips with the master plug and ring gages, spot-check flat tips on the test blocks, and record bending-moment and impact results for each lot. Store bits so tips are protected, reorder by exact designation, and remove any tool whose tip has rounded, chipped, or bent from the crib before it can damage a production fastener.
