Precision Screw & Bolt: Exceptional Value in Fasteners for Industry

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Pilot Hole Sizes

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 and zinc die castings and all alloys in Rockwell "B" hardness range 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.

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Precision Screw & Bolt, Inc.
1491 Chardon Road, Cleveland, Ohio 44117
tel. 216-522-1515 • fax. 216-522-0606
email: info@precisionscrewandbolt.com
www.precisionscrewandbolt.com