Pan Head Screw Thread and Clearance Hole Installation Design Tolerances

Mechanical Tolerance Standards Charts

The following is a recommended mechanical tolerance for the clearance hole size and threaded hole for standard ANSI Pan head fasteners.

Screw Reference: American National Standard Slotted Pan Head Machine Screws ANSI B18.6.3

Pan Head Screw

The following are medium fits.  These fits have been calculated using the Fixed Fastener case and are line to line in worst case misalignment and size departure.

SIZE HEAD
HEIGHT
TAPPED HOLE
POSITION TOL
True Position
CLEARANCE HOLE
DIA. TOL. LIMITS
HOLE POSITIONAL TOLERANCE
Position
HEAD DIAMETER COUNTERBORE DIA.
TOLERANCE LIMITS
.060-80
#0
.038 .010 .081
.076
.006 .116 .178
.162
.086-56/64
#2
.053 .012 .112
.105
.007 .167 .232
.210
.112-40/48
#4
.068 .016 .150
.142
.014 .219 .295
.273
.138-32/40
#6
.082 .022 .185
.174
.014 .270 .354
.330
.164-32/36
#8
.096 .024 .214
.202
.014 .322 .406
.382
.190-24/32
#10
.110 .028 .252
.236
.018 .373 .465
.441
.250-20/28 .144 .028 .312
.296
.018 .492 .562
.538
.3125-18/24 .178 .030 .381
.365
.022 .615 .689
.672
.375-16/24 .212 .030 .443
.427
.022 .740 .816
.797

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