Oberg, E. Jones, F. Horton, H. (1984). Machinery's Handbook, 22nd ed. New York: Industrial Press Inc. pp. 1157, 1159 The applicable standards that govern the Torq-set geometry are National Aerospace Standard NASM 33781 and NASM 14191 for the ribbed version. The ribbed version is also known as ACR Torq-set. [84] Tri-angle [ edit ] a b c d e f g h i Higgins, Matt (September 16, 2015). "What is the Difference: Screw Bits– Phillips vs. Pozidriv". Fine Homebuilding. 154 (November 2015): 38. Archived from the original on 2016-04-19 . Retrieved 2015-09-25.

The triple-square, also known as XZN, is a type of screw drive with 12 equally spaced protrusions, each ending in a 90° internal angle. The name derives from overlaying three equal squares to form such a pattern with 12 right-angled protrusions (a 12-pointed star). In other words, three Robertson squares are superimposed at a successive 30° rotation. The design is similar to that of the double-square—in both cases, the idea being that it resembles a square (Robertson) but can be engaged at more frequent angles by the driver bit. These screws can be driven with standard Robertson bits. Unlike JIS, the ISO 4757 standard for cross-head screws does not specify a dot on the screw head. [33] Phillips II [ edit ] Combo drive". Klien Tools. 3 November 2014. Archived from the original on March 11, 2015 . Retrieved 1 July 2022. A U-drive screw has a helical thread with an angle acute enough to be driven by a hammer or pressure from an arbor press, and thus has a domed head with no means of turning it. [92] These are most frequently driven into plastics with a pre-drilled pilot hole. Apple uses Y-type screws to secure the battery on the 2010 and 2011 MacBook Pro, as well as an extremely small type in the Apple Watch, iPhone 7 and iPhone X. [87] [88] This style of screw is often called a "tri-wing", although that name more properly belongs to a different design (see below).A thumbscrew is a type of screw drive with either a tall head and ridged or knurled sides, or a key-like flat-sided vertical head. They are intended to be tightened and loosened by hand, and are usually not found in structural applications. They are sometimes also cut for Phillips head or slotted screwdrivers, as well as having the knurling for finger grip. ASME Standard 18.6.8 covers dimensions for Type A (shoulder under the head), regular and heavy, along with Type B (without shoulder), regular and heavy. They can be found on many computer cases, and in other locations where easy access without tools is desired. 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. The manufacturing process for Pozidriv screwdriver bits requires a slightly more complex cutter than that for Phillips, however both can be manufactured in four cuts from a tapered blank. A combination slotted/hex head cap is often used for self-tapping screws for metal, where the hex head enables greater torque during the initial self-tapping installation, while allowing the convenience of a slotted screwdriver to be used for removal and reinsertion.

a b "Tork-Bolts". Loss Prevention Fasteners. Ultra Fasteners Inc. Archived from the original on 2015-09-26 . Retrieved 2015-09-25. Some screws have heads designed to accommodate more than one kind of driver, sometimes referred to as combo-head or combi-head. The most common of these are a combination of a slotted/Phillips head. Screwdriver bits". McMaster-Carr catalog (116thed.). p.2806. Archived from the original on 2019-12-14 . Retrieved 2010-06-11. Screw Holding Screw Driver" (PDF). Audiocraft Magazine: 7. April 1956. Archived (PDF) from the original on 2021-10-16 . Retrieved 2018-09-17.Lox: Screws Designed for Power Tools". www.lox.com. Archived from the original on 2017-12-09 . Retrieved 2017-12-24. The following are screw drives based on a cruciform shape; i.e., a cross shape. Other names for these types of drives are cross recessed, cross-head, cross tip, and cross-point. A double slotted screw drive is not considered cruciform because the shape is not recessed, and consists only of two superimposed simple milled slots. Some of these types are specified in ISO 4757, Cross recesses for screws. Digest, Reader's (2003). Family Handyman Best Projects, Tips and Tools. Reader's Digest. p.106. ISBN 978-0-7621-0455-0. Archived from the original on 2016-12-24 . Retrieved 2016-09-24.

Clutch Head Bit Set (Set of 4)". Vintage Trailer Supply. Archived from the original on 2020-08-13 . Retrieved 2020-09-05.

Product Variations

Care should be taken not to confuse the name of this pattern with the casual phrase "spline head" which usually refers to the XZN pattern. Slot screw drives have a single horizontal indentation (the slot) 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. Additionally, 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. Torx Paralobe is a further improvement over Torx Plus, [48] claiming 50% increased drive system torque over Torx and 20% over Torx Plus. JIS" or ISO 8764 standardized cruciform-blade screwdrivers are available for this type of screw, and should always be used to avoid head and driver damage.