Where a hand screwdriver fits in woodworking
Many screws in a project go in with a drill or impact driver, covered in the drill guide and the impact driver guide, along with their bits. A hand screwdriver is for the rest: hinges and hardware, small or brass screws, screws in finished work, and the final turn where you want to feel the screw seat. The skill is the same whichever you use — the tip has to fit the screw's recess.
The common drives
| Drive | Recess | Driver to use |
|---|---|---|
| Slotted | One straight slot across the head | A flat blade that fills the slot |
| Phillips | A cross; ISO 8764-1 calls the recess form H | A PH tip of the size the recess takes |
| Pozidriv | A cross; ISO 8764-1 calls the recess form Z | A PZ tip of the size the recess takes |
| Square | A square socket, sold by its maker as Robertson | A square tip of the matching size |
| Hexalobular | Six rounded lobes; ISO 10664's generic name for the drive sold as TORX® | A hexalobular tip of the matching size |
The recess, not the screw's gauge or length, decides the driver. Screw sizes themselves are on the wood screw size chart.
Phillips and Pozidriv are not interchangeable
The two cross recesses look alike, and that is where screws get damaged. ISO 8764-1 specifies two separate tip forms: PH for form H (Phillips) recesses and PZ for form Z (Pozidriv) recesses. Screwdriver maker PB Swiss Tools explains the difference in the flanks: a Phillips tip tapers toward its point, while a Pozidriv tip's flanks are parallel. Under high torque the tapered Phillips form produces a force that pushes the driver out of the screw — an effect PB Swiss says was originally used on purpose to limit torque — and the parallel Pozidriv form avoids it. PB Swiss adds that a Phillips driver can turn a Pozidriv screw, with some play, but that a Pozidriv driver cannot be used in a Phillips screw. Use PH in PH and PZ in PZ.
Square and hexalobular drives
A square recess takes a square tip; the company that makes Robertson screws sells it under that name and claims reduced cam-out for it. The six-lobed recess has a generic name, the hexalobular internal driving feature, which ISO 10664 standardises; TORX® is a trade name for it, and drivers are sold by size for it. In both cases, the tip should go fully into the recess before you turn.
Handles
Hand screwdrivers come with wooden and with plastic handles. Whatever it is made of, a handle should be sound: OSHA's hand-tool booklet says wooden handles must not be splintered. A handle's shape changes how it feels in the hand, but no maker reviewed here gives a torque figure for one shape against another, and BenchRoot does not rate them.
Using a screwdriver well
- Match the drive and the size, and seat the tip fully before turning.
- Hold the work steady, clamped if it can move, and keep your other hand away from the line the tip would take if it slipped.
- Drill pilot holes in hardwood first; sizes are in the pilot hole chart.
- Replace a worn or rounded tip rather than forcing it.
- Do not use a screwdriver as a chisel or pry bar; OSHA's booklet warns about the reverse misuse — a chisel used as a screwdriver can break and throw its tip.
Safety— Slips and misuse
A tip that does not fit its recess can slip out of it. Use the right tip, keep your free hand out of its path, and keep the work held. General shop rules are in woodworking safety rules.
Before driving a screw by hand
- Drive type identified: slotted, PH, PZ, square or hexalobular
- Tip size matches the recess
- Tip and handle in good condition
- Pilot hole drilled where the wood needs one
- Work held; free hand clear
Hammers are explained in the hammer guide, which maps this family; the wider kit in hand tools and tool sets.
Sources
Drive names and tip forms come from ISO 8764-1 and ISO 10664; the Phillips–Pozidriv account is PB Swiss Tools', and the maker's claims about its own drives are attributed to it. No screwdriver was tested. No torque figure is given for a hand screwdriver, and no table matches screw sizes to driver sizes: the screw's recess sets the driver, and screw dimensions are on the wood screw chart.
- 1.
ISO 8764-1:2004, Assembly tools for screws and nuts — Screwdrivers for cross-recessed head screws — Part 1: Driver tips. International Organization for Standardization, 2004.
Used for: Two forms of cross-recess driver tip, for hand drivers and machine bits: form PH for form H recesses and form PZ for form Z recesses.
- 2.
ISO 10664:2014, Hexalobular internal driving feature for bolts and screws. International Organization for Standardization, 2014.
Used for: The hexalobular internal driving feature for bolts and screws, its shape and basic dimensions.
- 3.
Phillips and Pozidriv cross-head screws – explained in simple terms. PB Swiss Tools, 2011.
Used for: PH and PZ as the ISO designations; Phillips flanks that taper toward the tip and Pozidriv flanks that are parallel; the conical Phillips form generating an ejection force at high torque, originally used intentionally to limit torque; a Phillips driver turning a Pozidriv screw with some play, while a Pozidriv driver cannot be used in a Phillips screw.
- 4.
Robertson: About. Robertson Inc. (Marmon Fasteners).
Used for: The Robertson square-drive system from the maker that sells it, with its own claim of reduced cam-out.
- 5.
Hand and Power Tools (OSHA 3080). Occupational Safety and Health Administration, 2002.
Used for: A chisel used as a screwdriver whose tip can break and fly off; wooden tool handles that must not be splintered.
About this guide
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