| 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
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
 |
CLEARANCE HOLE
DIA. TOL. LIMITS |
HOLE POSITIONAL TOLERANCE
|
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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