北京电影学院动画学院螺丝头型及垫圈种类(英文版)

2021年1月22日发(作者：上衣英语)
Fastener Basics

Common Fastener Types


Hex
bolts
,
or
hex
cap
screws,
are
used
in

machinery
and construction. Can be used
with
a
nut,
or
in
a
tapped
hole.
Fully
threaded
hex

bolts are also known as tap bolts.
Wood
screws
have
large
threads
and
a
smooth

shank f or pulling two pieces of material
together. They can be used in wood and other

soft materi-als.
Sheet
metal
screws
have
sharp
points
and

threads, and are designed to be driven directly
into
sheet
metal.
They
can
also
be
used
in

softer materials like plastic, fiberglass, or wood.
Machine screws
are fully threaded for use with
a

nut
or
in
a
tapped
hole.
Certain
types
are

some-times referred to as stove bolts.
Socket
screws
are
machine
screws
with
an

internal hex socket (Allen) drive. Longer lengths

may have a smooth shank.
Lag
bolts
,
or
lag
screws,
are
large
wood
screws

with hex heads. Typically used for wood

construction and landscaping.
Carriage bolts
have smooth, domed heads with

a
square
section
underneath
that
pulls
into
the

material to prevent spinning during installation.
Nuts
are
used
to
fasten
machine
threaded

fasteners
in
through-hole
applications.
Lock

nuts help prevent loosening.
Washers
spread
the
load
over
a
greater
surface

area
when
tightening
a
bolt,
screw
or
nut. Lock washers help preventing loosening.

Tip:
Find a more comprehensive fastener type chart


Grade/Class & Fastener Strength

Fastener
Grade

(US)
or
Class

(metric)
refers
to
the
mechanical
proper-ties
of
the
fastener
material.
Generally,
a
higher
number

indicates a stronger, more hardened (but also more brittle) fastener.
For a chart of fastener grades, head markings and mechanical properties, see

Bolt Depot’s Grade markings and Strength Chart


US bolt head markings

Metric bolt head markings



8.8

10.9

12.9

Low Carbon

Grade 5

Grade 8

Class 8.8

Class 10.9

Class 12.9
Note:
In addition to these markings, the head will often have a manufacturer stamp.

Page 1

Fastener Materials
Note:
Do
not
rely
on
this
guide
for
color-matching.
The

appearance of these materials sometimes di ers

signifi-cantly from the photos below.
Zinc-plated steel
is a

low carbon steel for
general use. Relatively
inexpensive, with the
zinc plating providing
moderate corrosion
resistance suitable for
indoors or otherwise
dry conditions. Color is
either a blue-ish tint or

yellow depending on the exact process.

Hot-dipped galvanized
steel
has a thicker zinc

coating for better
corrosion resistance,
making it suitable for
outdoor use. Because
of the thick plating,

only galvanized nuts and washers will fit
galvanized bolts. The coating typically has
a rough, dull grey finish.

Stainless steel
o
ers

good corrosion
resistance, making it
suitable for outdoor
use and marine
applications, but is

more expensive than zinc plated.

Chrome
and
nickel
plated steel
are

smooth and polished
for appearance. The

plating o ers moderate corrosion resistance.

Brass
and
bronze
are

copper alloys with good
corrosion resistance.
More expensive than
steel, these materials
are typically used for
decorative applications.
Colors can vary
significantly.

Alloy steel
is highly

hardened and usually
black oxide and/or oil
coated, o ering little
corrosion resistance.

How Fasteners are Notated: An Example







Machine screws, Phillips pan head, Stainless steel 18-8, #12-24 x 1










Fastener

type







Material




























Drive Types


Phillips

Head Styles
and


Hex heads
are typically


Slotted
drives are
used with larger bolts and
Phillips Slotted
common in screws,
screws, and tightened with

but prone to cam-

a wrench.
out (stripping).



Pan heads
have a slightly


Combo
drives, that

domed head that sits
can be used with
above the surface.
Combo

either driver, are


Flat heads
are installed in

available for many
a

countersunk hole for a

fastener types.


flat surface.

Frearson
and

Round heads
are tall domed

Pozidriv
are similar
heads, used primarily for
Frearson Pozidriv

to Phillips, but less

decorative purposes.

prone to cam- out.

Oval heads
are a low


Hex socket (Allen)
domed and countersunk
drives are compact
heads, used primarily
Hex socket
and easy to drive, but
for decorative purposes.


(Allen)
prone to cam-out.

Star

Truss heads
are slightly

and
Square
domed, with a wide head for

drive

are resistant to

an extra large surface area.
Star

Square
cam-out and can be
Socket heads
are narrow

(Robertson)
installed single-
with a socket drive, and
handed.

knurled or smooth sides.

Button heads
feature
Note:
Most
drive
types
(Frearson
and
a

medium dome.
Slotted

being
notable
exceptions)
require
Typically used with a
the correct driver size for proper installation.
hex socket drive.


Nut & Washer Sizes


Nut and washer sizes indicate
the screw or bolt they fit.
For example:




3/8”
-16 Hex Bolt

3
/8” Washer

3/8”
-16 Nut



Di erent washer patterns have di erent
outside

diameters.
For example, hardened US washers
are

available in
USS
(wider) and
SAE
(narrower)
patterns. Fender washers have large outside
diameters.


1/4”


1/4”
1/4” x 1”

SAE

USS

Fender

Page 2










Diameter

Length


Thread Count (TPI)











Measuring Diameter

For most
types of
fasteners,
the diameter

is measured on
the
outside
of

the threads.

Note:
US
diameters
under
1/4”
are
given
as
numbers
(e.g.

#12) instead of inches, in order of increasing size. If you need
to find the actual diameter, use a table corresponding to your
fastener type


Thread Count & Thread Pitch

Machine threaded fasteners specify a thread
density in
Threads Per Inch
(US) or as a
Thread


Pitch
in mm (Metric).
For a given diameter, a fastener may be
available in
coarse
(standard),
fine
and
sometimes
super

fine
thread.



Measuring Length
Fastener length is
usually measured from
where the material is
assumed to be to the
end of the fastener.
Thus, countersunk
fasteners are measured
overall and non-counter-
sunk fasteners are
measured from under
the head.
.