If you have only one Phillips head screwdriver, it is probably a #2 size. Wood screws often come in sizes 6 and 8.

Sizes are: M4, M5, M6, (M7), M8, (M9), M10, (M11), M12, (M13), M14, (M15), M16, (M17) and M18 (the sizes in parentheses are less commonly used, but they do exist). Despite the similar naming scheme to metric fasteners, there is no correlation between the name of the size and the dimensions of the tool. Some sizes (at least M14, M16, M18) are also available in a tamperproof version (with a center hole) Due to the difficulty of turning these fasteners without specialized (and uncommon) five-point wrenches such as hydrant wrenches, they are commonly used for tamper resistance by public utilities on water meter covers, natural gas valves, electrical cabinets, and fire hydrants.Different shaft lengths and handle sizes can make it easier to work on whatever you're working on. A longer shaft can allow you to access hard-to-reach areas where your hand won't fit.

Most tamper-resistant screw configurations rely on the common unavailability of corresponding drivers to reduce the likelihood of widespread tampering. True tamper-proof - rather than merely resistant - screw drives include the breakaway head and one-way screw drives. Try fitting a couple of screwdrivers into the head of the screw without being aggressive. Always test more than one because Phillips head screwdrivers come in multiple sizes that are very close to one another. Chilton, G. (2001). Homebasics: the complete guide to running today's home. Barnes & Noble Books. p. 18. ISBN 978-0-7607-2719-5 . Retrieved 27 September 2018.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. Adler, Alexander (1998-05-18). Testing and Understanding Screwdriver Bit Wear (Master's thesis). Virginia Tech. hdl: 10919/36701. The #2 Phillips head screwdriver fits screws 5, 6, 7, 8, and 9 and has a tip measurement of 3.5 mm. Crosshead screws, the type used with Phillips head screwdrivers, allow for a tighter fit than flathead screws. That's why this is the screw of choice for many manufacturers and builders.

Tri-Wing Screwdriver. "Tri-wing screwdriver: Types". Triwingscrewdrivers.com. Archived from the original on 2012-03-23 . Retrieved 2012-03-12. When people make mistakes using screwdrivers, the most common problem is using the wrong kind of screwdriver for the job at hand. Using the wrong kind of screwdriver, or the wrong size, could strip the screw. 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. [ citation needed] Hi-Torque [ edit ] Phillips head screwdrivers look distinctly different from other types of screwdrivers. The tip of a Phillips head will have pointed edges and a noticeable X shape. There are multiple sizes of Phillips head screwdrivers, with tip measurements sometimes varying by just half a millimeter. With such a small size difference, can’t you get away with using the wrong driver on the wrong screw?Phillips head screwdrivers in other sizes, such as #0 or #2, are known as ph0, ph2, and so forth. What is the most common Phillips head size? Screwdriver shanks are made with durable steel with hardened tips. The handle of the screwdriver is most commonly made with plastic, metal, or wood, primarily.