Project 5: Screws

Group Members: Antony Burt, Jason Nitz, Taylor House

Thread

Thread Form: Thread form is the different shapes of the threads in a cross-section

Thread Pitch: The thread pitch can be found by counting the number of threads in a given length. In the picture the pitch is found by counting 5 threads in one inch so the thread pitch is .200in. Make sure that when you are counting the treads that you start with zero, and that you place the steel rule on the edge of the thread.

Hand of the Thread: This just refers to the orientation of the threads. This determines what direction you turn the screw to tighten and loosen the screw.

Major Diameter: The major diameter can be bound in the first numbers in the thread designations. For example A ½-10, has a major diameter of .500in. Be sure to measure the major diameter on a section of the screw where the threads are not worn.

Minor Diameter: The minor diameter is the diameter of the underlying shaft of the screw.

Pitch Diameter: The pitch diameter is the diameter where the thread tooth and the thread space are equal.

Screw Thread Size Chart

Source

©1997-2005 Roton Products, Inc. All rights reserved.

Drills

The size of the drill is determined by the maximum drill bit shank that its chuck can accommodate. Chuck-end of drill that is adjustable to fit different sizes of drills
There are many different variants of the electric drill, and most of these are available as either mains operated drills, or battery powered cordless drills.

Hand Drill: Hand operated crank handle turns an interlocking gear, which also rotates the drill bit. Quicker set up time than the electric drill. Most useful when you require only a small number of holes. Effective for drilling into wood, soft metal, and plastics. Will generally accommodate most drill bits up to 6mm (1/4") in diameter in either keyed or keyless chucks, and can also be used for screw driving.

Breast Drill: Larger version of the hand drill, incorporating a plate to lean on to apply extra pressure while drilling.

Miniature Hand Drill: Particularly useful for fine work, the miniature hand drill bores holes with very small, high-speed steel bits. Useful for making pilot holes for small screws, some models have collars at both ends allowing the user to have different size drills available without having to change the bit.

Brace: Similar to the hand drill. Effective for drilling into wood, the brace will generally accept larger drill shanks than the hand drill, and can also be used for screw driving. Some models have a ratchet fitted to the chuck, allowing the user to drill/drive in places where a full rotation of the handle is not possible.

Joist Brace similar chuck and ratchet construction to the standard brace, the joist brace is especially useful for drilling in restricted spaces due to a frame that uses a lever at right angles to the line of the drill bit.

Push Drill: Mainly used for drilling pilot holes, the push drill uses very fine straight-fluted drill bits (known as drill points) that are rotated via a repetitive pushing motion.

Source

Source

Heads

Slotted: The original screw head, can be found anywhere.

Phillips: Very popular design, sizes include: #1,#2, and #3

Phillips Tamper-resistant: Not very common, has a pin in the middle and is not very strong so it is not used in high-torque applications.

Quadrex: Combination of Phillips and square

Pozidriv®: Common in Europe

Square Recess: Becoming popular because it is resistant to slippage of the driver

Square Recess Tamper-Resistant: Same design as square recess, but has a tamper resistant pin

Torx®: Used mostly in the electronics industry

Tamper-Resistant Torx®: Same as Torx but with a tamper resistant post in the middle

Torx Plus®: Enhanced Torx® design allowing more contact with the driver which allows more torque to be applied

Tamper-Resistant Torx Plus®: This is a licensed design and is for industrial use only

Tri-Wing®: Not very popular design only used in a small number of applications

Spanner: Used to avoid tampering

One Way Removal: Can be driven in with a normal flat edge, but sides are sloped so that it won’t be able to be taken out.

Source

Company Taner Bolt & nut corp.

Specifications

Based on what is needed for the screwing process, the screws will need many different specifications changed. When different materials are being screwed into, like metal, wood, or plastic, the screw size and type has to change. If it is a harder material like metal, than the screw needs to have a thicker body diameter. Other specifications that would change based on what is needed would be the screw and head diameter, the head height and the material thickness.

Chart/source

Grade

Grade identifys the right screw for the specific job you are doing. Grade two is used for jobs where a high amount of strenght in not required, such as wood. Grade 2 is identified buy the head of the screw being blank. Grade 5 is used for metals such as automotive engine repair, and it is identified by three radial lines on the head of the screw. Grade 8 is also used for automotive needs and other applications where high tensile strenght is required, and has even more strength than grade 5. Grade 8 is identified by 6 radial lines.

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