Thread Forming Fasteners For Standard Panel And Component Thicknesses

The unique “trilobular” shape of the Taptite screw roll forms a mating thread in an unthreaded pilot hole. The threads are work hardened as they are formed, providing a strong joint or assembly. By elastic recovery, the metal fills in behind the triangular lobes to provide maximum contact and a secure assembly. The tri-lobular shape of the screw shank reduces friction during driving to assure low driving torque, generates a prevailing torque that exceeds the level of locking screw; an interference fit provides resistance to vibrational loosening.

WCL offers Taptite screws in 4, 6, 8, 10 and 1/4″ diameters, lengths ranging from 1/4″ to 1″ in Phillips Pan Head and Slotted Indented Hex Head. All conventional head styles and drives, and other diameters and lengths and metric sizes are available on application.

See the following page for standard stocking parts. Note WCL is always adding to its broad base of inventory items.

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NOMINAL
SCREW
SIZE
DIA. OF
CIRCUMSCRIBED
CIRCLE (C) MIN.
DIA. OF
CIRCUMSCRIBED
CIRCLE (C) MAX.
MEASUREMENT
ACROSS
CENTER (D) MAX.
MEASUREMENT
ACROSS
CENTER (D) MIN.
SCREW POINT DIA. OF
CIRCUMSCRIBED
CIRCLE (Cp) MAX.
4-40 0.1145 0.1105 0.1095 0.1055 0.09
6-32 0.141 0.135 0.1095 0.1055 0.111
8-32 0.167 0.161 0.161 0.155 0.137
10-24 0.194 0.188 0.186 0.18 0.153
10-32 0.193 0.187 0.187 0.181 0.163
1/4-20 0.255 0.249 0.245 0.239 0.206

Recommended Pilot Hole Sizes Inch* Screws

MATERIAL
THICKNESS
INCH .020-.055 .061-.122 .125-.245 .250-.312 .313-.500 .375-.499 .500-.625
APPROX. U.S. GAUGE 26-17 16-11 41946 3-5/16″ 5/16″-1/2 3/8″-1/2″ 1/2″-5/8″
INCH NOMINAL
SCREW SIZE
DIA.-T.P.I.
MATERIAL PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
PILOT
HOLE
DIAMETER
4-40 STEEL ALUMINUM .098
.098
.102
.100
.104
.102
6-32 STEEL ALUMINUM .120
.120
.120
.120
.125
.125
.128
.125
8-32 STEEL ALUMINUM .147
.147
.150
.150
.154
.152
10-24 STEEL ALUMINUM .166
.166
.172
.166
.177
.170
10-32 STEEL ALUMINUM .173
.173
.177
.173
.180
.177
12-24 STEEL ALUMINUM .193
.191
.199
.196
.203
.199
.203
.203
1/4-20 STEEL ALUMINUM .219
.219
.224
.221
.228
.224
.234
.228
5/16-18 STEEL 0.281 0.285 0.285 0.29
3/8-16 STEEL 0.348 0.348 0.354 0.354
ALUMINUM:Aluminum sheet and bar (including aluminum and zinc die castings and all alloys in Rockwell “B”hardness range from 40 to 70) and other ductile materials of similar hardness, such as brass, bronze, etc.
Note: Special materials and applications may warrant special hole sizes. Information available on request.
*Metric sizes also available.
Note: Taptite and Taptite II are registered trademarks of Research Engineering and Manufacturing Incorporated.

Taptite® And Taptite® II Screws

Stocking Standard Taptites At WCL

WCL PRODUCT NUMBER WCL PRODUCT NUMBER WCL PRODUCT NUMBER
0256-0312 POZI PH TT 0632-0625 PPH TT2 1032-0375 PPH TT2
0440-0250 IHWH TT2 0632-0750 IHWH TT2 1032-0500 IHWH TT2
0440-0250 PPH TT2 0632-0750 PPH TT2 1032-0500 PPH TT2
0440-0312 IHWH TT2 0832-0250 IHWH TT2 1032-0625 IHWH TT2
0440-0312 PPH TT2 0832-0250 PPH TT2 1032-0625 PPH TT2
0440-0375 IHWH TT2 0832-0312 IHWH TT2 1032-0750 IHWH TT2
0440-0375 PPH TT2 0832-0312 PPH TT2 1032-0750 PPH TT2
0440-0500 IHWH TT2 0832-0375 IHWH TT2 1032-1000 IHWH TT2
0440-0500 PPH TT2 0832-0375 PPH TT2 1032-1000 PPH TT2
0440-0625 IHWH TT2 0832-0500 IHWH TT2 1224-0750 IHWH TT
0440-0625 PPH TT2 0832-0500 PPH TT2 2520-0375 IHWH TT2
0632-0187 PPH SERR TT 0832-0625 IHWH TT2 2520-0375 PPH TT2
0632-0250 IHWH TT2 0832-0625 PPH TT2 2520-0500 IHWH TT2
0632-0250 PPH TT2 0832-0750 IHWH TT2 2520-0500 PPH TT2
0632-0312 IHWH TT2 0832-0750 PPH TT2 2520-0625 IHWH TT2
0632-0312 PPH TT2 0832-1000 IHWH TT2 2520-0625 PPH TT2
0632-0375 IHWH TT2 0832-1000 PPH TT2 2520-0750 IHWH TT2
0632-0375 PPH TT2 1024-0375 IHWH TT2 2520-0750 PPH TT2
0632-0500 IHWH TT2 1024-0375 PPH TT2 2520-0875 IHWH TT2
0632-0500 PPH TT2 1024-0500 IHWH TT2 2520-0875 PPH TT2
0632-0500 TPH T-15 TT 1024-0500 PPH TT2 2520-1000 IHWH TT2
0632-0625 IHWH TT2 1032-0375 IHWH TT2 2520-1000 PPH TT2
Example: 0632-0625 PPH TT2 = 6-32 X 5/8 Phillips Pan Head Taptite II
Note: All Thread Forming Screws have a standard finish of Zinc and Wax. Other finishes are available.

Taptite® “Sems” Screws With Washers

Stocking Standard Taptite Sems At WCL

WCL PRODUCT NUMBER WCL PRODUCT NUMBER WCL PRODUCT NUMBER
0440-0500 PPH TT SQCN 0632-0375 IHH TRI/RD EXT 0832-0500 PPH TT SQCN
0440-0500 TPH T-10 TT SQCN 0632-0750 TPH T15 TT SQCN 1024-0375 IHH TT EXT
0440-0500 TPH T-9 TT SQCN 0632-0875 TPH T-15 TT SQCN
0632-0312 IHH TT EXT 0832-0375 PPH TT SQCN
Example: 0440 – 0500 TPH T9 TT SQCN = 4 – 40 x 1/2 Torx T9 Pan Head Taptite Square Cone (Square Dome).
Note: PPH = Phillips Pan Head. TPH = Torx® Pan Head. IHH = Indented Hex Head. IHWH = Indented Hex Washer Head. SERR = Serrated under head. TRI/RD = Tri Roundular. TT = Taptite®. TT2 = Taptite® II. T-9,T-10 etc.= Torx Bit Size. SQCN = Square Cone Washer. EXT = External Washer.
Note: Taptite and Taptite II are registered trademarks of Research Engineering and Manufacturing Incorporated.
Torx is a registered trademark of Camcar-Textron Incorporated.