Fasteners

Question 1

Define American National thread

Answer 1

A general use V shape thread

Question 2

Define left-hand thread

Answer 2

A thread that loosens and tightens in the opposite direction (e.g. on a bicycle pedal)

Question 3

Define square thread

Answer 3

A thread in a square shape that is ideal for power transmission

Question 4

Define acme thread

Answer 4

A trapezoidal thread that is stronger than a square thread (e.g. threads on a lead screw)

Question 5

Define buttress thread

Answer 5

A thread that is sloped on one side and vertical on another. Ideal for handling heavy forces in one direction (e.g. lifting machinery up)

Question 6

Define a slotted head

Answer 6

The most popular head designed to strip less

Question 7

Define a Philips head

Answer 7

A head in the shape of a cross designed to cam-out at a certain torque limit

Question 8

Define a Robertson head

Answer 8

A square shaped head with the highest torque tolerance. Commonly used in the automotive and furniture industry

Question 9

Define a Torx head

Answer 9

A star shaped head designed to prevent cam-out and stripped heads

Question 10

Define a set/grub screw

Answer 10

A screw without a head used to fix rotating parts on a shaft. Used only for light loads

Question 11

Define a shoulder bolt

Answer 11

A bolt that has a shank with a very precise diameter and a threaded portion with a smaller diameter. Used to locate the bolt on a part precisely

Question 12

Define a slotted/castle nut

Answer 12

A nut that is used with a split pin on a drilled bolt to permanently secure the nut in place

Question 13

Define pitch

Answer 13

Pitch is the distance from crest to crest on a thread (inverse of threads per inch)

Question 13

Define a wing nut

Answer 13

A nut with two wings that’s easy to adjust

Question 13

What is the format of metric threads

Answer 13

M (major diameter in mm) X (pitch in mm). For example: M12 X 1.75

Question 14

What is the format of imperial threads

Answer 14

(major diameter in inches) — (threads per inch) (course/fine series). For example: 5/8” — 18 UNF. Screws with diameter less than 1/4” are numbered with gauge sizes instead.

Question 15

What does UNF and UNC mean and what are advantages of each and common uses

Answer 15

Unified fine and unified course threads. Course threads for rugged applications in softer applications and are faster to remove and replace. Fine threads are slightly stronger (due to larger minor diameter), are easier to tap on tougher materials and will not wear with vibrations as easily.

Question 16

What angle are unified (imperial) threads

Answer 16

60 degrees

Question 17

What is a rivet and how do they work

Answer 17

A rivet is a smooth cylindrical shaft with a head on one end that is deformed to make a permanent fixture. A rivet gun is typically used on the head to pull a ball in the rivet and deform the shaft.

Question 18

Define anchor bolts

Answer 18

Bolts that dig into the side walls as it is fastened in (used to secure baseplates into concrete)

Question 19

Define NPT thread

Answer 19

National Pipe Taper thread. Used for fastening pipes. Are tapered so that the tighter it is, the more water tight it is (like a cone pushing against a countersink)