WIDTH OF SLOT FOR SLOTTED SCREWS

DIAMETER OF HEAD

  FH Pic OH Pic Round Head Pic TH Pic BH Pic Fillister Head Pic PH Pic  
Screw Sizes Flat Head     Oval Head Round Head Truss Head Binding Head Fillister Head Pan Head Width of Slot
Wood Machine Wood Machine Cap Machine
1 .146 .146 .138 .138       .118   .026
  .130 .130 .122 .122       .104   .019
2 .172 .172 .162 .162 .194 .181   .140 .167 .031
  .156 .156 .146 .146 .180 .171   .124 .155 .023
3 .199 .199 .187 .187 .226 .208   .161 .193 .035
  .181 .181 .169 .169 .211 .197   .145 .180 .027
4 .225 .225 .211 .211 .257 .235   .183 .219 .039
  .207 .207 .193 .193 .241 .223   .166 .205 .031
5 .252 .252 .236 .236 .289 .263   .205 .245 .043
  .232 .232 .217 .217 .272 .249   .187 .231 .035
6 .279 .279 .260 .260 .321 .290   .226 .270 .048
  .257 .257 .240 .240 .303 .275   .208 .256 .039
7 .305   .285   .352       .296 .048
  .283   .264   .333       .281 .039
8 .332 .332 .309 .309 .384 .344   .270 .322 .054
  .308 .308 .287 .287 .364 .326   .250 .306 .045
9 .358   .334             .054
  .334   .311             .045
10 .385 .385 .359 .359 .448 .339   .313 .373 .060
    .359 .334 .334 .425 .378   .292 .357 .050
12 .438 .438 .408 .408 .511 .454   .357 .425 .067
  .410 .410 .382 .382 .487 .430   .334 .407 .056
14 .491   .457             .075
  .461   .424             .064
1/4"   .507   .472 .573 .513 .375 .414 .492 .075
    .477   .443 .546 .488 .363 .389 .473 .064
16 .544   .506             .075
  .512   .476             .064
18 .597   .555             .084
  .563   .523             .072
5/16"   .635   .590 .698 .641 .437 .518 .615 .084
    .600   .557 .666 .609 .424 .490 .594 .072
20 .650   .604             .084
  .614   .570             .072
24 .756   .702             .094
  .716   .664             .081
3/8"   .762   .708 .823 .769 .562 .622 .740 .094
    .722   .670 .787 .731 .547 .590 .716 .081

When ordering slotted bits, please remember that head sizes and slot widths of hardened, self-tapping, and sheet metal screws do not conform to the same specifications as standard wood or machine screws described in the chart below. Also, because of variations in these dimensions among screws from different manufacturers, bits should be ordered to head and slot size rather than screw size.

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