TECHNICAL BULLETINInstallation of TA Thread-Rolling Screws for MetalsTA thread-rolling screws are an excellent choice for usewith drilled, extruded, punched or molded holes in ductilemetals and castings. The triangular out-of-round shapeforms strong threads by work-hardening the metal hostmaterial without creating unwanted chips or slivers. The design requires low installation torque and providesexcellent resistance to loosening caused by vibration.
Recommended Hole Diameters for Cold-Rolled Steel Sheets and Plates
All dimensions in inches
| Application |
Light |
Medium-Light |
Medium-Heavy |
Full Strength |
Extra Strength |
| ThreadEngagement Percentage |
90% |
85% |
80% |
75% |
70% |
| Thread |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
| 2-56 |
.017-.034 |
.0756 |
.034-.052 |
.0761 |
.052-.073 |
.0767 |
.073-.095 |
.0773 |
.095-.169 |
.0779 |
| 4-40 |
.022-.045 |
.0974 |
.045-.067 |
.0982 |
.067-.095 |
.0990 |
.095-.126 |
.0998 |
.126-.157 |
.1006 |
| 6-32 |
.028-.066 |
.1197 |
.066-.083 |
.1207 |
.083-.117 |
.1218 |
.117-.152 |
.1288 |
.152-.193 |
.1238 |
| 8-32 |
.033-.066 |
.1457 |
.066-.098 |
.1467 |
.098-.141 |
.1478 |
.141-.180 |
.1488 |
.180-.230 |
.1498 |
| 10-24 |
.038-.079 |
.1656 |
.079-.114 |
.1670 |
.114-.162 |
.1683 |
.162-.209 |
.1697 |
.209-.266 |
.1710 |
| 10-32 |
.038-.079 |
.1717 |
.079-.114 |
.1727 |
.114-.162 |
.1738 |
.162-.209 |
.1748 |
.209-.266 |
.1758 |
| 12-24 |
.043-.086 |
.1916 |
.086-.130 |
.1930 |
.130-.184 |
.1943 |
.184-.238 |
.1957 |
.238-.302 |
.1970 |
| 1/4-20 |
.050-.100 |
.2208 |
.100-.150 |
.2224 |
.150-.213 |
.2240 |
.213-.275 |
.2256 |
.275-.350 |
.2273 |
All dimensions in millimeters
| Application |
Light |
Medium-Light |
Medium-Heavy |
Full Strength |
Extra Strength |
| ThreadEngagement Percentage |
90% |
85% |
80% |
75% |
70% |
| Thread |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
MaterialThickness |
HoleDiameter |
| M2 .5 x 0.45 |
0.5-0.9 |
2.24 |
0.9-1.5 |
2.25 |
1.5-2.1 |
2.27 |
2.1-2.7 |
2.28 |
2.7-3.5 |
2.30 |
| M3 x 0.5 |
0.5-1.1 |
2.71 |
1.1-1.7 |
2.72 |
1.7-2.7 |
2.74 |
2.7-3.3 |
2.76 |
3.3-4.0 |
2.77 |
| M3.5 x 0.6 |
0.6-1.4 |
3.15 |
1.4-2.0 |
3.17 |
2.0-2.9 |
3.19 |
2.9-3.8 |
3.21 |
3.8-4.5 |
3.23 |
| M4 x 0.7 |
0.8-1.4 |
3.59 |
1.4-2.4 |
3.61 |
2.4-3.3 |
3.64 |
3.3-4.4 |
3.66 |
4.4-5.5 |
3.68 |
| M5 x 0.8 |
1.0-2.1 |
4.53 |
2.1-2.9 |
4.56 |
2.9-4.4 |
4.58 |
4.4-5.9 |
4.61 |
5.9-7.1 |
4.64 |
| M6 x 1 |
1.2-2.4 |
5.42 |
2.4-3.6 |
5.45 |
3.6-4.9 |
5.48 |
4.9-6.9 |
5.51 |
6.9-8.1 |
5.55 |
(1) Hole diameters are based on a calculation of .6495 x thread pitch x % thread engagement. PENCOM strongly recommends testing in the application to determine actual working dimensions.
Performance Data for Cold-Rolled Steel Sheets and Plates
All dimensions in inches unless noted
| Thread |
MaterialThickness |
HoleDiameter |
NearestDrill Size |
ThreadFormingTorque(in-lbs) |
Prevailing FirstRemovalTorque(in-lbs) |
Rec.AssemblyTorque(in-lbs) |
FailureTorque(in-lbs) |
| 2-56 |
.0469 |
.075 |
1.9mm |
1-2 |
.5-1 |
4 |
6-73 |
| .0625 |
.076 |
#48 |
1.2 |
.5-1 |
4 |
8-103 |
| .0938 |
.079 |
#47 |
1.2 |
.5-1 |
5 |
11-144 |
| 4-40 |
.0312 |
.098 |
#40 |
2-3 |
1-2 |
6 |
8-113 |
| .0625 |
.102 |
2.6mm |
3-4 |
1-2 |
9 |
15-183 |
| .0938 |
.102 |
2.6mm |
3-4 |
1-2 |
11 |
22-27 4 |
| 6-32 |
.0625 |
.120 |
#31 |
4-7 |
3-4 |
14 |
25-30 3 |
| .0938 |
.120 |
#31 |
6-9 |
3-5 |
20 |
35-45 5 |
| .1250 |
.125 |
1/8 |
6-9 |
4-6 |
22 |
39-45 4 |
| 8-32 |
.0938 |
.147 |
#26 |
10-13 |
5-7 |
30 |
65-75 3 |
| .1250 |
.150 |
3.8mm |
11-14 |
4-7 |
45 |
75-85 5 |
| .1875 |
.150 |
3.8mm |
16-20 |
8-11 |
45 |
75-95 4 |
| 10-24 |
.0938 |
.172 |
11/64 |
14-18 |
5-8 |
35 |
65-80 3 |
| .1250 |
.172 |
11/64 |
14-18 |
5-8 |
45 |
80-90 3 |
| .1875 |
.172 |
11/64 |
17-22 |
9-13 |
55 |
110-115 4 |
| 10-32 |
.0938 |
.173 |
#17 |
11-14 |
9-13 |
35 |
80-95 3 |
| .1250 |
.177 |
#16 |
12-16 |
9-13 |
50 |
110-120 3 |
| .1875 |
.177 |
#16 |
19-25 |
12-16 |
70 |
115-140 3 |
| 12-24 |
.1250 |
.196 |
#9 |
19-24 |
9-12 |
65 |
95-115 3 |
| .1875 |
.199 |
#8 |
21-26 |
9-13 |
75 |
135-155 3 |
| .2500 |
.203 |
13/64 |
21-26 |
10-14 |
85 |
150-170 4 |
| 1/4-20 |
.1250 |
.224 |
5.7mm |
30-36 |
18-25 |
85 |
170-195 3 |
| .1875 |
.224 |
5.7mm |
45-55 |
25-35 |
125 |
205-235 4 |
| .2500 |
.228 |
#1 |
55-65 |
25-35 |
125 |
205-235 4 |
- Values determined under laboratory conditions using carbon steel hex washer head screws zinc plated and wax coated driven into cold-rolled steel members at low speeds. PENCOM strongly recommends testing in the application to determine actual working performance values.
- Recommended assembly torques represent approximately 30-50ksi clamping pressure.
- Failure most likely a result of threads stripping.
- Failure most likely a result of screw breakage.
- Failure most likely a result of threads stripping or screw breaking.
Performance Data for Cold-Rolled Steel Sheets and Plates (Cont.)
All dimensions in millimeters unless noted
| Thread |
MaterialThickness |
HoleDiameter |
NearestDrill Size |
ThreadFormingTorque(N-m) |
Prevailing FirstRemovalTorque(N-m) |
Rec.AssemblyTorque(N-m) |
FailureTorque(N-m) |
| M3 x 0.5 |
1.0 |
2.71 |
#36 |
0.30-0.45 |
0.15-0.30 |
1.0 |
1.5-2.0 3 |
| 2.0 |
2.75 |
2.75mm |
0.35-0.55 |
0.15-0.30 |
1.0 |
1.6-2.5 3 |
| 3.0 |
2.75 |
2.75mm |
0.50-0.80 |
0.25-0.40 |
1.6 |
2.5-3.5 5 |
| M4 x 0.7 |
2.0 |
3.60 |
3.6mm |
0.60-0.85 |
0.30-0.40 |
1.8 |
2.8-3.8 3 |
| 3.0 |
3.66 |
#27 |
0.90-1.3 |
0.50-0.70 |
3.3 |
5.5-7.5 5 |
| 4.0 |
3.66 |
#27 |
1.2-1.6 |
0.60-0.85 |
4.3 |
7.0-10 5 |
| M5 x 0.8 |
2.5 |
4.57 |
#15 |
1.3-2.0 |
0.60-0.80 |
2.8 |
5.3-8.0 3 |
| 3.5 |
4.57 |
#15 |
1.5-2.7 |
0.90-1.5 |
6.0 |
10-12 3 |
| 5.0 |
4.60 |
4.6mm |
2.0-3.0 |
0.90-1.5 |
7.0 |
11-14 5 |
| M6 x 1 |
3.0 |
5.41 |
#3 |
2.0-2.8 |
0.60-1.2 |
5.0 |
9.0-13 3 |
| 4.5 |
5.50 |
5.5mm |
3.2-4.5 |
0.90-1.5 |
10.0 |
16-21 3 |
| 6.0 |
5.50 |
5.5mm |
3.5-4.8 |
1.0-1.7 |
10.0 |
18-25 5 |
- Values determined under laboratory conditions using carbon steel hex washer head screws zinc plated and wax coated driven into cold-rolled steel members at low speeds. PENCOM strongly recommends testing in the application to determine actual working performance values.
- Recommended assembly torques represent approximately 207-345MPa clamping pressure.
- Failure most likely a result of threads stripping.
- Failure most likely a result of screw breakage.
- Failure most likely a result of threads stripping or screw breaking.
Recommended Extruded Hole Diameters for Light-Gauge Carbon Steel
All dimensions in inches
| MaterialThickness |
.02 |
.03 |
.04 |
.06 |
.09 |
.13 |
.16 |
.19 |
| Thread |
Hole Diameter |
| 6-32 |
.118-.120 |
.118-.121 |
.120 |
.120-.123 |
.122-.125 |
— |
— |
— |
| 8-32 |
.140-.150 |
.140-.150 |
.150 |
.150 |
.147-.150 |
.148-.152 |
— |
— |
| 10-24 |
.160-.170 |
.160-.170 |
.164-.167 |
.165-.168 |
.166-.170 |
.168-.173 |
— |
— |
| 10-32 |
.170-.172 |
.170-.173 |
.171-.174 |
.172-.175 |
.173-.176 |
.174-.177 |
— |
— |
| 12-24 |
.190 |
.190 |
.190-.193 |
.191-.194 |
.192-.196 |
.193-.197 |
.195-.200 |
.198-.203 |
| MaterialThickness |
.04 |
.06 |
.09 |
.13 |
.16 |
.19 |
.22 |
.25 |
| Thread |
Hole Diameter |
| 1/4-20 |
.218-.220 |
.218-.221 |
.219-.223 |
.221-.225 |
.224-.228 |
.227-.231 |
.228-.233 |
.230-.235 |
(1) Dimensions are suggestions only. PENCOM strongly recommends testing in the application to determine actual working dimensions.
Recommended Extruded Hole Diameters for Light-Gauge Carbon Steel (Cont.)
All dimensions in millimeters
| MaterialThickness |
0.5 |
0.8 |
1.1 |
1.6 |
2.4 |
3.6 |
4.4 |
| Thread |
Hole Diameter |
| M2.5 x 0.45 |
2.21-2.24 |
2.22-2.26 |
2.25-2.28 |
2.27-2.30 |
— |
— |
— |
| M3 x 0.5 |
2.68-2.71 |
2.71-2.74 |
2.74-2.77 |
2.77-2.80 |
2.80-2.83 |
— |
— |
| M3.5 x 0.6 |
3.11-3.15 |
3.13-3.18 |
3.16-3.21 |
3.19-3.24 |
3.24-3.29 |
3.27-3.32 |
— |
| M4 x 0.7 |
— |
3.55-3.59 |
3.58-3.62 |
3.60-3.65 |
3.64-3.68 |
3.69-3.73 |
— |
| M5 x 0.8 |
— |
— |
4.48-4.53 |
4.51-4.56 |
4.54-4.59 |
4.57-4.62 |
— |
| M6 x 1 |
— |
— |
5.35-5.42 |
5.38-5.45 |
5.41-5.48 |
5.44-5.51 |
5.49-5.56 |
(1) Dimensions are suggestions only. PENCOM strongly recommends testing in the application to determine actual working dimensions.
Recommended Dimensions for Extruded Light-Gauge Carbon Steel
All dimensions in inches
| HoleDiameter |
Material Thickness T |
| .024-.035 |
.042-.048 |
.060 |
.090 |
.106 |
.122 |
| H |
R |
H |
R |
H |
R |
H |
R |
H |
R |
H |
R |
| .081-.100 |
.040 |
.005 |
.040 |
.005 |
.040 |
.006 |
.043 |
.010 |
— |
— |
— |
— |
| .101-.130 |
.047 |
.005 |
.047 |
.005 |
.047 |
.006 |
.052 |
.010 |
.054 |
.010 |
— |
— |
| .131-.150 |
.053 |
.005 |
.053 |
.005 |
.053 |
.006 |
.060 |
.010 |
.063 |
.010 |
.072 |
.013 |
| .151-.180 |
— |
— |
.060 |
.005 |
.081 |
.006 |
.070 |
.010 |
.075 |
.010 |
.087 |
.013 |
| .181-.220 |
— |
— |
.070 |
.005 |
.070 |
.006 |
.090 |
.010 |
.095 |
.010 |
.104 |
.013 |
| .221-.260 |
— |
— |
— |
— |
.075 |
.006 |
.100 |
.010 |
.105 |
.010 |
.120 |
.013 |
| .261-.300 |
— |
— |
— |
— |
.083 |
.006 |
.116 |
.010 |
.125 |
.010 |
.140 |
.013 |
| .301-.340 |
— |
— |
— |
— |
— |
— |
.130 |
.010 |
.140 |
.010 |
.164 |
.013 |
| .341-.380 |
— |
— |
— |
— |
— |
— |
.140 |
.010 |
.155 |
.010 |
.170 |
.013 |
| .381-.430 |
— |
— |
— |
— |
— |
— |
.150 |
.010 |
.170 |
.010 |
.184 |
.013 |
All dimensions in millimeters
| HoleDiameter |
Material Thickness T |
| 0.61-0.89 |
1.07-1.22 |
1.52 |
2.29 |
2.69 |
3.10 |
| H |
R |
H |
R |
H |
R |
H |
R |
H |
R |
H |
R |
| 2.06-2.54 |
1.02 |
0.13 |
1.02 |
0.13 |
1.02 |
0.15 |
1.09 |
0.25 |
— |
— |
— |
— |
| 2.57-3.30 |
1.19 |
0.13 |
1.19 |
0.13 |
1.19 |
0.15 |
1.32 |
0.25 |
1.37 |
0.25 |
— |
— |
| 3.33-3.81 |
1.35 |
0.13 |
1.35 |
0.13 |
1.35 |
0.15 |
1.52 |
0.25 |
1.60 |
0.25 |
1.83 |
0.33 |
| 3.84-4.57 |
— |
— |
1.52 |
0.13 |
1.55 |
0.15 |
1.78 |
0.25 |
1.91 |
0.25 |
2.21 |
0.33 |
| 4.60-5.59 |
— |
— |
1.78 |
0.13 |
1.78 |
0.15 |
2.29 |
0.25 |
2.41 |
0.25 |
2.64 |
0.33 |
| 5.61-6.60 |
— |
— |
— |
— |
1.91 |
0.15 |
2.54 |
0.25 |
2.67 |
0.25 |
3.05 |
0.33 |
| 6.63-7.62 |
— |
— |
— |
— |
2.11 |
0.15 |
2.95 |
0.25 |
3.18 |
0.25 |
3.58 |
0.33 |
| 7.65-8.64 |
— |
— |
— |
— |
— |
— |
3.30 |
0.25 |
3.56 |
0.25 |
3.91 |
0.33 |
| 8.66-9.65 |
— |
— |
— |
— |
— |
— |
3.56 |
0.25 |
3.94 |
0.25 |
4.32 |
0.33 |
| 9.68-10.92 |
— |
— |
— |
— |
— |
— |
3.81 |
0.25 |
4.32 |
0.25 |
4.67 |
0.33 |
(1) Dimensions are suggestions only. PENCOM strongly recommends testing in the application to determine actual working dimensions.
Recommended Dimensions for Extruded Light-Gauge Carbon Steel (Cont.)Recommended Hole Dimensions for Aluminum and Zinc Die-Castings
All dimensions in inches
| Thread |
Cast HoleDiameter 1 |
CastBossDiameterC Min. |
DrilledHoleDiameterD 1 |
EdgeDistanceW Min. |
ThreadEngagement LengthL Min. |
| A |
B |
| 2-56 |
.078-.081 |
.074-.077 |
.197 |
.0779 |
.046 |
.172 |
| 4-40 |
.102-.105 |
.096-.099 |
.220 |
.1006 |
.065 |
.224 |
| 6-32 |
.125-.128 |
.119-.122 |
.242 |
.1238 |
.081 |
.276 |
| 8-32 |
.152-.155 |
.145-.148 |
.272 |
.1498 |
.081 |
.328 |
| 10-24 |
.174-.177 |
.165-.168 |
.315 |
.1710 |
.108 |
.380 |
| 10-32 |
.179-.182 |
.171-.174 |
.315 |
.1758 |
.081 |
.380 |
| 12-24 |
.200-.203 |
.191-.194 |
.359 |
.1970 |
.108 |
.432 |
| 1/4-20 |
.232-.235 |
.221-.224 |
.415 |
.2273 |
.130 |
.500 |
All dimensions in millimeters
| Thread |
Cast HoleDiameter 1 |
CastBossDiameterC Min. |
DrilledHoleDiameterD 1 |
EdgeDistanceW Min. |
ThreadEngagement LengthL Min. |
| A |
B |
| M2 x 0.4 |
1.83-1.91 |
1.73-1.81 |
3.32 |
1.82 |
1.00 |
4.00 |
| M2.5 x 0.45 |
2.31-2.39 |
2.20-2.28 |
4.15 |
2.29 |
1.20 |
5.00 |
| M3 x 0.5 |
2.82-2.90 |
2.68-2.76 |
4.98 |
2.77 |
1.30 |
6.00 |
| M3.5 x 0.6 |
3.23-3.31 |
3.13-3.21 |
5.81 |
3.23 |
1.60 |
7.00 |
| M4 x 0.7 |
3.74-3.82 |
3.56-3.64 |
6.64 |
3.68 |
1.80 |
8.00 |
| M5 x 0.8 |
4.72-4.80 |
4.50-4.58 |
8.30 |
4.64 |
2.10 |
10.00 |
| M6 x 1 |
5.66-5.74 |
5.40-5.48 |
9.96 |
5.54 |
2.60 |
12.00 |
- Hole diameters provide approximately 65% to 75% of thread engagement.
- Dimensions are suggestions only. PENCOM strongly recommends testing in the application to determine actual working dimensions.
TA Thread-rolling screws are available in a variety of head styles, drives, lengths, materials and finishes. Custom configurations such as SEMS washers, dog points and partially threaded shanks for “captive” applications are possible as well. Speak with a PENCOM Account Manager to learn more.
