CLEARANCE HOLE CHART


Clearance hole chart for inch fasteners according to ASME B18.2.8

Clearance Holes for Inch Fasteners
Nominal Screw Size Fit Class - Normal Fit Class - Close Fit Class - Loose
Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter
Min. Max. Min. Max. Min. Max.
#0 #48 0.076 0.082 #51 0.067 0.071 3/32 0.094 0.104
#1 #43 0.089 0.095 #46 0.081 0.085 #37 0.104 0.114
#2 #38 0.102 0.108 3/32 0.094 0.098 #32 0.116 0.126
#3 #32 0.116 0.122 #36 0.106 0.110 #30 0.128 0.140
#4 #30 0.128 0.135 #31 0.120 0.124 #27 0.144 0.156
#5 5/32 0.156 0.163 9/64 0.141 0.146 11/64 0.172 0.184
#6 #18 0.170 0.177 #23 0.154 0.159 #13 0.185 0.197
#8 #9 0.196 0.203 #15 0.180 0.185 #3 0.213 0.225
#10 #2 0.221 0.228 #5 0.206 0.211 B 0.238 0.250
1/4 9/32 0.281 0.290 17/64 0.266 0.272 19/64 0.297 0.311
5/16 11/32 0.344 0.354 21/64 0.328 0.334 23/64 0.359 0.373
3/8 13/32 0.406 0.416 25/64 0.391 0.397 27/64 0.422 0.438
7/16 15/32 0.469 0.479 29/64 0.453 0.460 31/64 0.484 0.500
1/2 9/16 0.562 0.572 17/32 0.531 0.538 39/64 0.609 0.625
5/8 11/16 0.688 0.698 21/32 0.656 0.663 47/64 0.734 0.754
3/4 13/16 0.812 0.824 25/32 0.781 0.789 29/32 0.906 0.926
7/8 15/16 0.938 0.950 29/32 0.906 0.914 1-1/32 1.031 1.051
1 1-3/32 1.094 1.106 1-1/32 1.031 1.039 1-5/32 1.156 1.181
1-1/8 1-7/32 1.219 1.235 1-5/32 1.156 1.164 1-5/16 1.312 1.337
1-1/4 1-11/32 1.344 1.360 1-9/32 1.281 1.291 1-7/16 1.438 1.463
1-3/8 1-1/2 1.500 1.516 1-7/16 1.438 1.448 1-39/64 1.609 1.634
1-1/2 1-5/8 1.625 1.641 1-9/16 1.562 1.572 1-47/64 1.734 1.759

Supplements:

Link Usage
Clearance hole calculator Calculator form of the clearance hole chart.

Reference:

  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc.
  • ASME B18.2.8-1999, Clearance holes for bolts, screws and studs