1. Industrial Skills
Fasteners & Hardware

2. Fasteners are used in manufactured products for several basic purposes:
They simplify manufacture.
They simplify repairs.
They provide safety.

3. When selecting a fastener for a particular use, consider these factors:
Strength: Will it hold the loads and pressures?
Security: Will it remain attached?
Cost: Realistic?
Installation: Appropriate for situation?
Skill: Is specialized training needed?
Equipment: Is specialized equipment needed and available?
Appearance: If the fastener shows, which kind looks best?

4. Nails – Most common method of fastening one wooden member to another.
Simple & quick
May not result in the strongest of joints
Variety of shapes and sizes
Each type designed for a particular purpose
Drive nails at angles slanting toward or away from each other to get best holding power
Nails are
designated
by “penny” size,
originally a term
which related to price
per hundred but now
signifies length. The symbol
for penny is the lowercase letter
“d”. Nail diameter increases with
length. Nails are now sold by the pound.

5. Screws – A large and important family of fasteners.
“Mechanical devices for fastening things together. it penetrates only by being turned, as with a screwdriver.”
The most common types of screws are:
Wood screws
Sheet-metal screws
Machine screws
Set screws

6. Wood Screws Serve much the same purpose as a nail, but:
greater holding power
easily removed and replaced.
neater in appearance and offer more decorative possibilities.
In addition to fastening pieces of wood together – the most common use of wood screws would be to anchor objects (hardware) to a wood surface.

7. Sheet-Metal Screws
Also called “Tapping Screws” or “Self-Threading Screws”.
Used to fasten light pieces of metal together or to attach covers, panels and other light parts.
These screws have sharp threads that can cut their own grooves into metal.
Distinguishable from wood screws in that they are threaded all the way from the point to the head.

8. Machine Screws
Used for the assembly of metal parts and usually are driven into “threaded” holes rather than drawn tight with nuts.
there are many head designs to choose from.
Machine screw threads are also designated by the number of threads per inch, just like bolt threads:
A 6-32 machine screw has a #6 body diameter and 32 threads per inch of length.
Most machine screws are fully threaded to the head.

9. Set Screws
Frequently used to hold a knob, collar, pulley or gear to a rotating shaft.
There are a variety of “head” or “point” styles, each best suited for its job.
Not an especially strong type of fastening – depend on friction and “shear” to hold parts together.

10. Once you have decided to use screws, in addition to the use category, you must consider four things before ordering.
Type of head
Material made of
The length
The diameter

11. The “type of head” should include both the “shape” and the “style”.
Screw Head “Styles”
Screw Head “Shapes”
Pan Head
Flanged Hex Head
Truss Head
Hex Head

12. The most common material screws are made of is steel.
When exposed to “weather”, coatings offer more protection.
Steel Blued
Zinc Coated
Chromium
Galvanized
Nickel
Silver Plate
Gold Plate
Marine Applications
Stainless Steel
Aluminum
Copper
Brass
Bronze
Synthetic Materials (Plastic or Nylon)

13. Screw Dimensions Length commonly range from ¼ inch to 4 inches.
Shorter or longer lengths are generally special order items.
Metric lengths are also available

14. Screw Dimensions Diameter
expressed by the “gauge” number or by the fraction of an inch.
metric diameters are expressed in mm

15. American Screw Gauge
Diameters less than ¼ inch (6 mm) use gauge number.
Diameters greater than ¼ inch use fractions of an inch.
Wood screws are an exception to this rule in that they generally go up to a #20 gauge (21/64”).

16. Bolts Machine Bolts: Carriage Bolt: Square or hex head
Usually used in plain holes drilled through the parts being fastened.
Generally held in place with a nut.
Carriage Bolt:
Round headed bolt
Commonly used for fastening wood parts
Square neck under head
Generally held in place with a nut

18. Threads
Threads – External helical ribs on the body of a bolt. Usually a bolt “mates” with internal threads of a nut.
Threads are measured by counting the number per inch. (Metric threads are measured by the distance between threads – pitch – in mm)
Thread gauges are available that match threads against those on the gauge.

21. Nuts and Washers
have internal threads so that a bolt may screw into it. The threads must match!
Threads per inch or distance between threads can be determined with a thread gauge just like bolt threads.
Nuts have three important dimensions:
Thickness
Distance across the flats
Inside diameter (same as that of the bolt with which it is to be used).

23. Washers
They are paired with and matched to bolts and nuts