List of screw drives

At a minimum, a screw drive is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. Some of the less-common drives are classified as being "tamper-resistant".
Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00".

Overview

Slotted drives

Thickness	Width	Torque
0.4	2.0	0.3
0.4	2.5	0.4
0.5	3.0	0.7
0.6	3.0	1.1
0.6	3.5	1.3
0.8	4.0	2.6
1.0	4.5	4.5
1.0	5.5	5.5
1.2	6.5	9.5
1.2	8.0	11.5
1.6	8.0	20.5
1.6	10.0	25.6
2.0	12.0	48.0
2.5	14.0	87.5

Slot

Slot screw drives have a single horizontal indentation in the fastener head and is driven by a "common blade" or flat-bladed screwdriver. This form was the first type of screw drive to be developed, and, for centuries, it was the simplest and cheapest to make because it can just be sawed or filed. Blunt or damaged tools can easily be re-ground as required in any workshop. It is unique because the slot head is straightforward to manufacture, and because it can be driven by a simple handtool. The slotted screw is commonly found in existing products and installations, along with use in simple carpentry work and in applications where minimal torque is needed. Slot screws are also used in the restoration of antique furniture, vehicles, and equipment.
However, this design is not well-suited for installation by power tools, given that a power driver often cams out of the slot; this often causes damage to the screw and surrounding material. For this reason, cruciform-slotted along with drives have replaced the slot drive in numerous applications. The tool used to drive a slot is called a common blade, flat-blade, slot-head, flat-tip or flat-head / flathead screwdriver. A hollow-ground screwdriver is less likely to cam out, so more torque can be applied without damaging the screw head. Flat-blade jeweler's screwdrivers and the tips found in drive sets are generally hollow-ground. Note that it is this typical chisel shape which allows 9 screwdriver sizes to drive 24 different slotted screw sizes, with the drawbacks of not fitting as closely as a hollow-ground screwdriver would, and increasing the possibility of damaging the fastener or surrounding area.
ISO 2380-1 specifies the internationally standardized shape and dimensions of the tips of screwdrivers for slotted-head screws as well as the minimum test torque the blade-to-handle connection shall withstand. Screwdriver tips are generally designated by blade thickness × width in mm, e.g. 1.2 × 6.5 which roughly matches a classic North American -inch screwdriver although the North American one is often a bit thinner.
At least one mechanical method of temporarily holding a slotted screw to a matching screwdriver is available, the Quick-Wedge screw-holding screwdriver, first manufactured by the Kedman Company in the 1950s.
Dzus fasteners, which have a cam-lock body instead of a threaded body, use a slot drive.

Coin-slot

Coin-slot drives are so-called because of the curved bottom of the recess, which facilitates driving them with a suitable coin. They are often used on items where the user is not likely to have a screwdriver when needed, such as recessed screws that attach cameras to tripod adapters, and battery compartments in some equipment such as children's toys.

Hi-Torque

Hi-Torque slot drives were designed by Alcoa Fastening Systems, for situations where very high torque is needed, along with the ability to repeatedly install and remove the fastener. The design features curved walls, unlike the straight-walled slot drive.
The Type II design adds a conical cup that receives a centering pin on the driver, improving the alignment of the driving tool to the fastener recess.

Cruciform drives

The following are screw drives based on a cruciform shape. Other names used for these types of drives are cross recessed, cross-head, cross tip, and cross-point; sometimes "plus" as against a simple slot's "minus". A double slotted screw drive is not considered cruciform because the shape is not recessed, and consists only of two orthogonal simple milled slots. Some of these types are specified in ISO 4757, Cross recesses for screws.
Cruciform Phillips and Pozidriv/Supadriv screws and screwdrivers look similar, and are often confused with each other; a Phillips screwdriver will often work with Pozidriv/Supadriv screws, but risks damaging the head of tight screws, while a Pozidriv/Supadriv screwdriver will damage a Phillips screw.

Cross

A cross or double-slot screw drive, not a true cruciform drive in that the entire cross is not engaged, has two slots, perpendicular to each other, in the fastener head; a slotted screwdriver is used to drive either of the slots. This type is usually found in cheaply-made roofing bolts and the like, where a thread of or above has a large flattened pan head. They provide some measure of redundancy: should one slot become deformed, the second may still be used.

Phillips

Driver size	Wood screw size	Machine screw size
#0	#0–1	M1.6, M2 or #0, #1
#1	#2–4	M2.5, M3 or #2, #3, #4
#2	#5–9	M3.5, M4, M5 or #5–10
#3	#10–16	M6 or #12, in., plus in. if round-head
#4	#18–24	M8, M10 or in., in., plus in. if flat-head
#5		in., in.

The Phillips screw drive was created by John P. Thompson, who, after failing to interest manufacturers, sold his design to businessman Henry F. Phillips. Phillips is credited with forming a company, improving the design, and promoting the adoption of his product. The original 1932 patent expired in 1966, but the Phillips Screw Company continued to develop improved designs.
The American Screw Company of Providence, Rhode Island, was responsible for devising a means of efficiently manufacturing the screw, and successfully patented and licensed their method; other screw makers of the 1930s dismissed the Phillips concept because it called for a relatively complex recessed socket shape in the head of the screw, as distinct from the simple milled slot of a slotted screw. The Phillips screw design was developed as a direct solution to several problems with slotted screws: high cam-out potential; need for precise alignment to avoid slippage and damage to driver, fastener, and adjacent surfaces; and difficulty of driving with powered tools.
Phillips drive bits are often designated by the letters "PH", plus a size code 0000, 000, 00, 0, 1, 2, 3, or 4 ; the numerical bit size codes do not necessarily correspond to nominal screw size numbers.
The design is often criticized for its tendency to cam out at lower torque levels than other "cross head" designs. There has long been a popular belief that this was a deliberate feature of the design, to assemble aluminium aircraft without overtightening the fasteners. There is no good evidence for this suggestion, and the property is not mentioned in the original patents.

Pozidriv

The Pozidriv, sometimes incorrectly spelled "Pozidrive", is an improved version of the Phillips screw drive. It is designated "Type IA" by ANSI standards, and "Type Z" in ISO documents. The Pozidriv was patented by GKN Screws and Fasteners in 1962. It was designed to allow more torque to be applied and greater engagement than Phillips drives. As a result, the Pozidriv is less likely to cam out. It is similar to, and compatible with, the Supadriv screw drive.
Pozidriv screwdrivers are often designated using the letters "PZ" followed by a size code of 0, 1, 2, 3, 4 or 5. The numbers do not correspond to nominal screw size numbers. PZ1 is normally used in screws with nominal diameters of, PZ2 in screws and PZ3 in. These sizes roughly correspond to the Phillips head numbers.
Pozidriv screws have a set of radial indentations set at 45° from the main cross recess on the head of the screw, which makes them visually distinct from Phillips screws.
While a Phillips screwdriver has slightly tapered flanks, a pointed tip, and rounded corners, a Pozidriv screwdriver has parallel flanks, a blunt tip, and additional smaller ribs at 45° to the main slots. Both Phillips and Pozidriv bit types can be manufactured in four cuts from a tapered blank, although Pozidriv screwdriver bits require a slightly more complex cutter than for Phillips bits.
Pozidriv and Phillips look broadly interchangeable, but may cause damage if mixed. Pozidriv screwdrivers will jam fit into Phillips screws, but when tightened they may slip or tear out the Phillips screw head. Conversely, while Phillips screwdrivers will loosely fit and turn Pozidriv screws, they will cam out if enough torque is applied, potentially damaging the screw head or driver.

Supadriv

The Supadriv screw drive is very similar in function and appearance to Pozidriv. It is a later development by the same company. The description of the Pozidriv head applies also to Supadriv. While each has its own driver, the same screwdriver heads may be used for both types without damage; for most purposes it is unnecessary to distinguish between the two drives. Pozidriv and Supadriv screws are slightly different in detail; the later Supadriv allows a small angular offset between the screw and the screwdriver, while Pozidriv has to be directly in line.
In detail, the Supadriv screwhead is similar to Pozidriv but has only two identification ticks, and the secondary blades are larger. Drive blades are about equally thick. The main practical difference is that Supadriv has superior bite when driving screws into vertical or near-vertical surfaces, making screwdriving more efficient, with less cam-out.