Types of screw heads pdf file

Screwdrivers date back to the early 15th century, when they were invented to tighten the newlyinvented screws used in metal suits of armor and engines for war. It consists of two eyes or recesses at the edge of the screw head. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Trim head an option to flat head screws, providing a narrower head. However, not much has changed in the technology of screws and their drivers, and the only real developments during the past several hundred years was an increase in the. The type and scope of these additional tests and who is to carry out and document them is to.

Fastener categories continued mating screws mating screws have a. Examples of fastener specification for the various fastener types are given later in this document. The robertson screw with a square head came out in 1908, the phillips head screw was invented in 1930, and tiny screws often found in gadgets such as iphones and laptops were introduced in the 21st century. Types of lug nuts types of construction nails wood screws vs. Most din standards for these bolt types have been withdrawn years ago. From a total of more than,000 different items in stock we. Simply knowing the head type on a screw or bolt can let you know what type of screwdriver or socket type you will need so you do not strip or cross thread your fastener. Hex bolts carriage bolts lag bolts bolts with a hexagonal head with threads for use with a nut or tapped hole. Screwhead buying guide chart showing 60 types of screws, screw heads, bolts, nuts and washers chart finding the right type of screw head for your project when there are hundreds of combinations of the drive type and head shape can be confusing, especially for beginning diyers.

There are several types of screw heads such as pan head, round head, mushroom head, oval head, bugle head, cheese head, dome head, and many other types of head. Media in category drawings of screw heads the following 200 files are in this category, out of 201 total. Machine screws with no head for screwing all the way into threaded holes. Different types of screw heads soon came out in the late 1900s. Cheat guide chart bolts, screws, washers, nuts, drive. Most commonly used in the bulk production of bolts, screws. Bolts with a smooth rounded head that has a small square section underneath. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. Fastener type chart bolt depot nuts and bolts, screws. Fastener guides screws head styles fastener superstore. A round or oval, domeshaped screw head is often used if you want.

Screw type fasteners are manufactured with different head styles. Sometimes the style serves a functional purpose, and sometimes its more decorative in nature. The following heads are categorized based on commonality, with some of the lesscommon drives being classified as tamperresistant. Screws and bolts are used to fasten materials by the engagement of the screw thread with a similar female thread internal thread in the matching part. Understanding screw heads and drive styles fastener mart. Screw heads are differentiated based on their shapes. You may do so in any reasonable manner, but not in. A screw and a bolt see differentiation between bolt and screw below, are similar types of fastener typically made of metal, and characterized by a helical ridge, known as a male thread external thread. The second is to house the drive, or the means by which force is applied to drive the screw in or remove it, if required. Nonetheless, triwing screws can be tightened to very high torque values, and they come in sizes that range from 1 to 3. This file is licensed under the creative commons attributionshare alike 3.