McFeely's 2022 Catalog - Catalog - Page 3
Screw Size Comparisons
Not sure which size you need? The drawings below are as accurate as possible to help in deciding which size is required
for your job. In addition, the following guidelines may help you select the proper size:
#4 Designed for very, light duty small crafts, jewelry boxes, hinges, etc.
Available in 3/8” to 3/4” lengths.
#6 Light duty designed for small crafts, hinges and drawer slides,
children’s furniture toys, light duty jigs and fixtures, etc. Available in 1/2”
to 1-1/2” lengths.
#8 General furniture construction, cabinets, light construction. Good all
purpose screw, for furniture construction, cabinets and light construction
in 5/8” to 3” lengths.
#10 General construction screw for heavy-duty furniture, outdoor
projects, decks, lawn furniture, boat building, etc. are available in 1/4” to
4” lengths.
#12 & 14 For heavy-duty construction, hanging solid-core doors, etc.
Available in 3/4” to 6” lengths in selected styles.
A Word About Drill Bits
Drilling the correct pilot hole
In addition to their superior performance, Square Drive screws
are also easier to install than most “garden variety” hardware
store screws. Since the screw shank is straight throughout
its entire length (except for the point), drilling a pilot hole
with a straight drill bit yields excellent results. The reduced
shank diameter at the head means an enlarged body hole isn’t
necessary. Finally, the straight bit doesn’t require the critical
depth control needed with a tapered bit.
If you’re still using the old style, cut-thread wood screws,
tapered-shank drill bits are the only way to go. They fit
the profile of the screw almost perfectly, so they provide
maximum holding power. In one step, they drill the proper
size hole for both the shank and the threaded portions of
the screw. The only caution – make sure the hole depth
matches the screw penetration into the second piece of wood!
Otherwise, the screw may not develop full holding power.
Drill Bit Size Recommendations
Screw Length
Brad Point
Unfortunately, there is really no hard and fast rule concerning the appropriate screw
length. Sometimes you don’t have much choice as to length because of the joint
configuration. In general, the screw should always go through the thinner piece first
and thread into the thicker piece.
In choosing length, try to have about two-thirds of the screw threaded into the
secondary piece, as shown. As the thickness of the lumber or fastener length
increases, this ratio can be reduced so that only half of the shank is threaded into the
secondary piece. Not coincidentally, only two-thirds of the shank is threaded on most
of our 1” and longer screws.
The table is a starting point − a quick technique is to hold
a drill bit up to the shank of the screw. If you’re breaking
screws, try enlarging the pilot hole − even 1/64” will make
a difference. Normally, the proper bit is the same size as the
shank between the threads. In practice, use a slightly larger
bit for hardwoods and a slightly smaller one for soft wood.
The root diameter of a Square Drive screw is smaller than
that of a standard “wood screw;” pilot recommendations are
also smaller.
Screw Dimensions
We’ve listed screw dimensions for Production Screws in two forms − a table
showing the maximum and minimum decimal dimensions, and a table showing
the maximum fractional dimensions. NOTE: The fractional dimensions are the
closest approximations to the actual decimal dimensions.
“A”
Pan Head
Size
Max
Min
Max
4
0.225
0.1945
6
0.279
0.244
8
0.332
0.292
0.322
10
0.385
0.340
12
0.438
0.389
14
0.507
0.452
Square Drive Screws
(Use Brad or Standard Point Drill Bits)
“A”
Round Washer Head
“B”
Body Dia
“C”
Thread DIa
Mid
T Max
Max
Min
T Max
Max
Min
Max
Min
0.219
0.205
0.086
N/A
N/A
N/A
0.095
0.084
0.116
0.105
0.270
0.256
0.103
N/A
N/A
N/A
0.118
0.107
0.142
0.131
0.306
0.120
0.376
0.352
0.110
0.136
0.125
0.168
0.157
0.373
0.357
0.137
0.443
0.411
0.125
0.157
0.146
0.194
0.183
0.425
0.407
0.153
N/A
N/A
N/A
0.176
0.165
0.220
0.209
0.492
0.473
0.175
N/A
N/A
N/A
0.201
0.190
0.246
0.235
Note: IFI Standards specify a tolerance on screw length of +0”, −1/16”.
“A”
Pan Head
“A”
Flat Head
Standard Point
Drill bit selection, for Square Drive screws and other fasteners,
should take into consideration the material’s properties. When
using harder materials, or “soft” screws, larger pilot holes are
required.
Having said that, our ProMax® screws are designed with the perfect thread
configuration for common joints. In general ProMax® screws have a longer than
standard unthreaded shank length to ensure that the screw doesn’t cross thread at
the joint..
“A”
Flat Head
Taper Point
“A”
Round Washer Head
“B”
Body Dia
“C”
Thread DIa
Max
Size
Max Dia
Max Dia
T Max
Min
T Max
Max
4
7/32
7/32
3/32
N/A
N/A
3/32
1/8
6
9/32
17/64
7/64
N/A
N/A
1/8
9/64
8
21/64
21/64
1/8
3/8
7/16
9/64
11/64
10
25/64
3/8
9/64
7/16
1/8
5/32
3/16
12
7/16
27/64
5/32
N/A
N/A
11/64
7/32
14
1/2
31/64
11/64
N/A
N/A
13/64
1/4
Screw
#4
#6
#8
#10
#12
#14
Hardwoods
5/64 Pilot
7/64 Pilot
1/8 Pilot
9/64 Pilot
5/32 Pilot
11/64 Pilot
Softwoods
1/16 Pilot
3/32 Pilot
7/64 Pilot
1/8 Pilot
9/64 Pilot
5/32 Pilot
Plug Sizes
1/4
3/8
3/8
1/2
1/2
1/2
Standard Wood Screws
(Using Taper Point Drill Bits)
Screw
#4
#6
#8
#10
#12
#14
Hardwoods
7/64 Pilot
9/64 Pilot
11/64 Pilot
13/64 Pilot
7/32 Pilot
1/4 Pilot
Questions? Email us at tech@McFeelys.com | Need more info? Call us at 1-800-443-7937.
Softwoods
3/32 Pilot
1/8 Pilot
5/32 Pilot
3/16 Pilot
13/64 Pilot
15/64 Pilot
Plug Sizes
1/4
3/8
3/8
1/2
1/2
1/2
2
