Professional plastic fastener manufacturers

Home Page

Introduction

News

Product

Article

Position：Home page>>Info>>Enterprise information>>Info阅读

| Setting Home page | Collect | Chinese |SN：ace69222987

Info阅读

Types of screw drives

时间：2015/5/7 8:22:52 作者：来源：浏览：人次

Main article: List of screw drives

Common types

External types

External drives are characterized by a female tool and a male fastener.

A screw drive is the system used to turn a screw. At a minimum, it is a feature on the screw 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. The following heads are categorized based on commonality,

with the less common drives being classified as "tamper-resistant".

Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00" or "Torx T5". These sizes do not describe a

particular dimension of the drive shape, but are arbitrary designations in the same sense as a "Size 8" shoe or dress.

Square This screw drive uses square fastener heads. They can be turned with an adjustable wrench, open-end wrench, or 8- or 12-point sockets. Common in the 19th and early 20th centuries, when it was easier and thriftier to manufacture than most other drives, it is

less common today (although still easy to find) because the external hex is now cost-competitive and allows better access for wrenching despite nearby obstructions, with fewer degrees of swing on each stroke.

A hex screw drive uses six-sided fastener heads. The fastener is known as a hex head cap screw. It can be turned with an adjustable wrench, combination wrench, and 6-

or 12-point sockets. The hex drive is better than square drive for locations where surrounding obstacles limit wrenching access, because smaller

wrench-swing arcs can still successfully rotate the fastener.

A pentagon screw drive uses five-sided fastener heads. The fastener is known as a penta screw. They require a special five-point socket in order to be turned. Water meter covers, natural gas valves, and electrical cabinets are commonly secured with penta

fasteners. It is also common in the U.S. for fire hydrants to have valves with a pentagon drive.

Slotted types

The slot screw drive has a single slot in the fastener head and is driven by a flat-bladed screwdriver. It was the first type of screw drive to be developed, and for centuries it was the simplest and cheapest

to make. The slotted screw is common in simple woodworking applications, but is not often seen in applications where a power

tool would be used because a power driver tends to slip out of the head and potentially damage the surrounding material. The

tool used to drive a slot is called a standard, flat-blade, slot-head, flat-tip, or flat-head screwdriver.

A cross-recess screw drive has two slots, oriented perpendicular to each other, in the fastener head; a slotted screwdriver is still

used to drive just one of the slots. This type is usually found in cheaply made roofing bolts and the like, where a thread of

5 mm (0.20 in) or above has a large flattened pan head. The sole

advantage is that they provide some measure of redundancy: should one slot be deformed in service, the second may still be

used.

Cruciform types

See also: cross-slotted, Torq-set, and Phillips/square

The following are screw drives based on a cruciform shape, i.e. a cross shape. Other names for these types of drives are

cross-head and cross-point. (Cross-type slotted screw drives are not considered cruciform because the shape is not recessed.)

Created by Henry F. Phillips, the Phillips screw drive was purposely designed to cam out when the screw stalled,to prevent

the fastener damaging the work or the head, instead damaging the driver. This was caused by the relative difficulty in

building torque limiting into the early drivers.

Phillips drive sizes (different from the screw size) are designated 0000, 000, 00, 0, 1, 2, 3, and 4 (by order of increasing

size).

The Frearson screw drive, also known as the Reed and Prince screw drive, is similar to a Phillips but the Frearson has a

sharp tip and larger angle in the V shape. One advantage over the Phillips drive is that one driver or bit fits all screw

sizes.

The Mortorq drive, developed by the Phillips Screw Company, is a format used in automotive and aerospace applications. It is

designed to be a lightweight, low-profile and high-strength drive, with full contact over the entire recess wing reducing risk of stripping.

Pozidriv

Screws with the Pozidriv head.

The Pozidriv, sometimes purposely misspelled Pozidrive to avoid trademark infringment, screw drive is an improved version of

the Phillips screw drive. They can be unscrewed with a regular Phillips screwdriver. It is jointly patented by the Phillips

Screw Company and American Screw Company. The name is thought to be a portmanteau of positive drive.

Supadriv

The Supadriv (sometimes found incorrectly as "Supadrive") screw drive is very similar in function and appearance to

Pozidriv—indeed, the two are often thought to be identical—and is a later development by the same company. The description of the Pozidriv head applies also to Supadriv.

Robertson

A Robertson, also known as a square, or Scrulox screw drive has a square-shaped socket in the screw head and a square protrusion on the tool. Both the tool and the socket have a taper, which makes

inserting the tool easier, and also tends to help keep the screw on the tool tip without the user needing to hold it there.

Hex socket

Main article: Hex key

Hex socket screws

The hex socket screw drive has a hexagonal recess and may be driven by a hex wrench, also known as an Allen Wrench, Allen

key, hex key or inbus as well as by a hex screwdriver (also known as a hex driver) or bit. Tamper-resistant versions with a pin in the recess are available.

	Screw head shapes	2015-05-07
	Types of screw drives	2015-05-07
	Thread standards	2015-05-07