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Camming Out
Cam out (also cam-out or camming out) is a process by which a screwdriver slips out of the head of a screw being driven once the torque required to turn the screw exceeds a certain amount. Repeatedly camming out damages the screw, and possibly also the screwdriver, and should normally be avoided. Phillips screwdriver The Phillips screwdriver design has a tendency to cam out during operation due to angled contact surfaces, which create an axial force pushing the driver out of the recess as torque is applied. Despite popular belief, there is no clear evidence that this was a deliberate design feature. When the original patent application was filed in 1933, the inventors described the key objectives as providing a screw head recess that (a) may be produced by a simple punching operation and which (b) is adapted for firm engagement with a driving tool with "no tendency of the driver to cam out". Nevertheless, the tendency of the Phillips screw to easily cam out was found to be an adv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screwdriver
A screwdriver is a tool, manual or powered, used for turning screws. Description A typical simple screwdriver has a handle and a shaft, ending in a tip the user puts into the screw head before turning the handle. This form of the screwdriver has been replaced in many workplaces and homes with a more modern and versatile tool, a power drill, as they are quicker, easier, and can also drill holes. The shaft is usually made of tough steel to resist bending or twisting. The tip may be hardened to resist wear, treated with a dark tip coating for improved visual contrast between tip and screw—or ridged or treated for additional "grip". Handles are typically wood, metal, or plastic and usually hexagonal, square, or oval in cross-section to improve grip and prevent the tool from rolling when set down. Some manual screwdrivers have interchangeable tips that fit into a socket on the end of the shaft and are held in mechanically or magnetically. These often have a hollow handle that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw
A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the screw head, head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The #Differentiation between bolt and screw, difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a Nut (hardware), nut. The screw head on one end has a slot or other feature that commonly requires a tool to transfer the twisting force. Common tools for driving screws include screwdrivers, wrenches, coins and hex keys. The head is usually larger than the body, which provides a ''bearing surface'' and keeps the screw from being driven deeper than its length; an exception being the ''set screw'' (aka grub screw). The cylindrical portion of the screw from the underside of the head t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . Just as a linear force is a push or a pull applied to a body, a torque can be thought of as a twist applied to an object with respect to a chosen point; for example, driving a screw uses torque to force it into an object, which is applied by the screwdriver rotating around its axis to the drives on the head. Historical terminology The term ''torque'' (from Latin , 'to twist') is said to have been suggested by James Thomson and appeared in print in April, 1884. Usage is attested the same year by Silvanus P. Thompson in the first edition of ''Dynamo-Electric Machinery''. Thompson describes his usage of the term as follows: Today, torque is referred to using d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phillips Screwdriver
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 Slot 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. 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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
