Standard/Specialty Industrial machine screws and industrial fasteners, including Lo-Driv Screws and Tri-Round screws, are available in various diameters and materials. The chart below lists the Lo-Driv and Tri-Round recommended pilot hole sizes for both inch and metric screws.
Lo-Driv & Tri-Round Recommended Pilot Holes Sizes – Inch Screws |
||||||
| Material Thickness Inch Nominal Screw Size Diameter – TPI | Inch Approx.US Gauge Material | .020 – .055 26 – 17 Diameter |
.061 – .122 16 – 11 Diameter |
.125 – .245 11 – 3 Diameter |
.250 – .312 3 – 5/16″ Diameter |
.313 – .500 5/16″ – 1/2″ 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 |
||
| 1/4 – 20 | Steel Aluminum |
.219 .219 |
.224 .221 |
.228 .224 |
.234 .228 |
|
| 5/16 – 18 | Steel Aluminum |
.281 .278 |
.288 .284 |
.290 .286 |
||
| 3/8 – 16 | Steel Aluminum |
.342 .339 |
.348 .343 |
.350 .343 |
||
Lo-Driv & Tri-Round Recommended Pilot Holes Sizes – Metric Screws |
||||||
| Material Thickness Nominal Screw Size Dia. Pitch | Millimeters Material |
.05 – 1.2 Diameter | 1.3 – 2.4 Diameter | 2.5 – 4.0 Diameter | 4.1 – 5.9 Diameter | 6.0 – 8.1 Diameter |
| M3 x 0.5 | Steel | 2.72 | 2.74 | 2.77 | ||
| M4 x .07 | Steel | 3.58 | 3.60 | 3.63 | 3.68 | |
| M5 x 0.8 | Steel | 4.55 | 4.57 | 4.60 | 4.65 | |
| M6 x 1.0 | Steel | 5.41 | 5.46 | 5.51 | 5.54 | |
| M7 x 1.0 | Steel | 6.45 | 6.51 | 6.58 | ||
| M8 x 1.25 | Steel | 7.31 | 7.39 | 7.47 | ||
| M10 x 1.50 | Steel | 9.10 | 9.17 | 9.27 | ||
| * Steel: Low carbon sheet and bar; average Rockwell – “B”55 – 75.** Aluminum: Aluminum sheet and bar (including aluminum andzinc die castings and all alloys in Rockwell “B” hardnessrange from 40 – 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 upon request. | ||||||