<s>
Computer	B-General_Concept
case	I-General_Concept
screws	I-General_Concept
are	O
the	O
hardware	O
used	O
to	O
secure	O
parts	O
of	O
a	O
PC	B-Device
to	O
the	O
case	B-General_Concept
.	O
</s>
<s>
Although	O
there	O
are	O
numerous	O
manufacturers	O
of	O
computer	B-General_Concept
cases	I-General_Concept
,	O
they	O
have	O
generally	O
used	O
three	O
thread	O
sizes	O
.	O
</s>
<s>
The	O
#6	O
-32	O
UNC	O
screws	O
are	O
often	O
found	O
on	O
3.5	B-Device
"	I-Device
hard	B-Device
disk	I-Device
drives	I-Device
and	O
the	O
case	B-General_Concept
's	O
body	O
to	O
secure	O
the	O
covers	O
.	O
</s>
<s>
The	O
M3	O
threaded	O
holes	O
are	O
often	O
found	O
on	O
5.25	B-Device
"	I-Device
optical	O
disc	O
drives	O
,	O
3.5	B-Device
"	I-Device
floppy	B-Device
drives	I-Device
,	O
and	O
2.5	O
"	O
drives	O
.	O
</s>
<s>
Motherboards	B-Device
and	O
other	O
circuit	O
boards	O
often	O
use	O
a	O
#6	O
-32	O
UNC	O
standoff	O
.	O
</s>
<s>
#4	O
-40	O
UNC	O
thumb	O
screws	O
are	O
often	O
found	O
on	O
the	O
ends	O
of	O
DVI	B-Protocol
,	O
VGA	B-Protocol
,	O
serial	B-Protocol
and	O
parallel	B-Device
connectors	I-Device
.	O
</s>
<s>
It	O
is	O
by	O
far	O
the	O
most	O
common	O
screw	O
found	O
inside	O
computer	B-General_Concept
cases	I-General_Concept
.	O
</s>
<s>
Nearly	O
every	O
brand	O
new	O
computer	B-General_Concept
case	I-General_Concept
comes	O
with	O
a	O
bag	O
of	O
these	O
.	O
</s>
<s>
Because	O
they	O
are	O
used	O
in	O
places	O
where	O
high	O
torque	O
is	O
not	O
required	O
and	O
easy	O
removal	O
and	O
replacement	O
may	O
be	O
desirable	O
(	O
such	O
as	O
on	O
the	O
side	O
panels	O
of	O
the	O
PC	B-General_Concept
case	I-General_Concept
)	O
,	O
they	O
are	O
frequently	O
available	O
as	O
thumbscrews	O
with	O
larger	O
,	O
knurled	O
heads	O
that	O
can	O
be	O
removed	O
with	O
one	O
's	O
fingers	O
or	O
tools	O
.	O
</s>
<s>
The	O
M3	O
is	O
the	O
second	O
most	O
common	O
screw	O
found	O
in	O
PCs	B-Device
.	O
</s>
<s>
Nearly	O
every	O
brand-new	O
computer	B-General_Concept
case	I-General_Concept
comes	O
with	O
a	O
bag	O
of	O
these	O
.	O
</s>
<s>
Most	O
cases	O
use	O
threaded	O
brass	O
standoffs	O
(	O
Jack	O
Screw	O
Standoffs	O
)	O
for	O
attaching	O
the	O
motherboard	B-Device
to	O
the	O
case	B-General_Concept
chassis	O
.	O
</s>
<s>
Because	O
the	O
case	B-General_Concept
material	O
is	O
usually	O
a	O
conductive	O
metal	O
,	O
attaching	O
the	O
motherboard	B-Device
directly	O
to	O
it	O
can	O
cause	O
a	O
short	B-Application
circuit	I-Application
.	O
</s>
<s>
The	O
standoff	O
provides	O
a	O
margin	O
of	O
space	O
between	O
the	O
motherboard	B-Device
and	O
the	O
case	B-General_Concept
to	O
keep	O
the	O
multiple	O
solder	O
points	O
below	O
from	O
grounding	O
and	O
short-circuiting	O
.	O
</s>
<s>
Usually	O
,	O
the	O
standoff	O
has	O
a	O
#6	O
-32	O
UNC	O
male	O
thread	O
on	O
one	O
end	O
which	O
screws	O
into	O
a	O
threaded	O
hole	O
in	O
the	O
case	B-General_Concept
or	O
motherboard	B-Device
backplate	O
and	O
a	O
#6	O
-32	O
UNC	O
female	O
thread	O
in	O
the	O
other	O
end	O
which	O
accepts	O
a	O
screw	O
to	O
retain	O
the	O
motherboard	B-Device
.	O
</s>
<s>
Less	O
often	O
,	O
the	O
standoff	O
has	O
a	O
female	O
thread	O
in	O
both	O
ends	O
and	O
a	O
second	O
screw	O
is	O
used	O
to	O
attach	O
it	O
to	O
the	O
case	B-General_Concept
.	O
</s>
<s>
Some	O
standoffs	O
use	O
the	O
M3	O
female	O
thread	O
(	O
which	O
faces	O
the	O
motherboard	B-Device
)	O
instead	O
of	O
#6	O
-32	O
UNC	O
,	O
and	O
on	O
a	O
rare	O
occasion	O
a	O
mixture	O
of	O
types	O
can	O
be	O
used	O
in	O
the	O
same	O
case	B-General_Concept
.	O
</s>
<s>
Typically	O
,	O
M2.5	O
and	O
M3	O
standoffs	O
tighten	O
with	O
a	O
5	O
mm	O
socket	O
,	O
M4	O
standoffs	O
with	O
a	O
6	O
mm	O
socket	O
,	O
M5	O
standoffs	O
with	O
a	O
7	O
mm	O
socket	O
,	O
and	O
M6	O
standoffs	O
with	O
an	O
8	O
mm	O
socket	O
,	O
but	O
this	O
is	O
not	O
always	O
the	O
case	B-General_Concept
.	O
</s>
<s>
Version	O
2.1	O
of	O
the	O
ATX	B-Language
specification	O
states	O
that	O
the	O
length	O
of	O
standoffs	O
needs	O
to	O
be	O
at	O
least	O
,	O
with	O
their	O
cross	O
sections	O
fitting	O
within	O
square	O
areas	O
centered	O
around	O
each	O
mounting	O
hole	O
on	O
ATX	B-Language
motherboards	B-Device
.	O
</s>
<s>
Pairs	O
of	O
#4	O
-40	O
UNC	O
thumbscrews	O
are	O
used	O
to	O
fasten	O
certain	O
connectors	B-Protocol
to	O
hardware	O
ports	O
.	O
</s>
<s>
The	O
screws	O
are	O
typically	O
located	O
on	O
either	O
side	O
of	O
D-subminiature	B-Protocol
connectors	I-Protocol
such	O
as	O
on	O
VGA	B-Protocol
,	O
serial	B-Protocol
,	O
parallel	B-Device
and	O
legacy	B-Device
game	B-Protocol
controller	I-Protocol
ports	I-Protocol
.	O
</s>
<s>
They	O
are	O
also	O
more	O
recently	O
used	O
on	O
DVI	B-Protocol
connectors	I-Protocol
.	O
</s>
<s>
The	O
typical	O
length	O
for	O
a	O
#4	O
-40	O
screw	O
used	O
in	O
PCs	B-Device
is	O
(	O
)	O
.	O
</s>
