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screws

screws. Tamper resistance screw:- A screw which the driver to open it is rarely find Objective is to protect that devices from the attacker bcoz they maybe they don’t have the driver. Tampering.

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screws

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  1. screws Tamper resistance screw:- A screw which the driver to open it is rarely find Objective is to protect that devices from the attacker bcoz they maybe they don’t have the driver. Bear propertys……

  2. Tampering • Tampering involves the deliberate altering or adulteration of a product, package, or system. Solutions may involve all phases of product production, packaging, distribution, logistics, sale, and use. No single solution can be considered as "tamper proof". Often multiple levels of security need to be addressed to reduce the risk of tampering. Some considerations might include: • * Identify who a potential tamperer might be: psychopath, misguided joker, saboteur, organized criminals, terrorists. What level of knowledge, materials, tools, etc. might they have? • * Identify all feasible methods of unauthorized access into a product, package, or system. In addition to the primary means of entry, also consider secondary or "back door" methods. • * Improve the tamper resistance to make tampering more difficult, time-consuming, etc. • * Add tamper-evident features to help indicate the existence of tampering. • * Educate people to watch for evidence of tampering. Bear propertys……

  3. Safety(tampering) • Nearly all mains appliances and accessories can only be opened with the use of a screwdriver (or a substitute item such as a nail file or kitchen knife). This prevents children and others who are careless or unaware of the dangers of opening the equipment from doing so and hurting themselves (from electrical shocks, burns or cuts, for example) or damaging the equipment. Sometimes (especially in order to avoid litigation), manufacturers go further and use tamper resistant screws, which cannot be unfastened with standard equipment. Tamper resistant screws are also used on electrical fittings in many public buildings primarily to reduce tampering or vandalism that may cause a danger to others. Bear propertys……

  4. Triwing screw Bear propertys……

  5. Head layout for screws Bear propertys……

  6. Name for head…from upper left.. • bristol Bear propertys……

  7. Screws and bolts • A screw used as a threaded fastener consists of a cylindrical shaft, which in many cases tapers to a point at one end, and with a helical ridge or thread formed on it, and a head at the other end which can be rotated by some means. The thread is essentially an inclined plane wrapped around the shaft. The thread mates with a complementary helix in the material. The material may be manufactured with the mating helix using a tap, or the screw may create it when first driven in (a self-tapping screw). The head is specially shaped to allow a screwdriver or wrench (British English: spanner) to rotate the screw, driving it in or releasing it. The head is of larger diameter than the body of the screw and has no thread so that the screw can not be driven deeper than the length of the shaft, and to provide compression. • Screws can normally be removed and reinserted without reducing their effectiveness. They have greater holding power than nails and permit disassembly and reuse. • The vast majority of screws are tightened by clockwise rotation; we speak of a right-hand thread. Screws with left-hand threads are used in exceptional cases, when the screw is subject to anticlockwise forces that might undo a right-hand thread. Left-hand screws are used on rotating items such as the left-hand grinding wheel on a bench grinder or the left hand pedal on a bicycle (both looking towards the equipment) or hub nuts on the left side of some automobiles. • Threaded fasteners were made by a cutting action such as dies provide, but recent advances in tooling allow them to be made by rolling an unthreaded rod (the blank) between two specially machined dies which squeeze the blank into the shape of the required fastener, including the thread. This method has the advantages of work hardening the thread and saving material. A rolled thread can be distinguished from a thread formed by a die as the outside diameter of the thread is greater than the diameter of the unthreaded portion of the shaft. Bicycle spokes, which are just bolts with long thin unthreaded portions, always use rolled threads for strength. Bear propertys……

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