Last updated 10 August 2026
It depends on the alloy, the process and the grain direction, and no table can tell you. Parts have been measured moving ten thousandths in one axis. Measure your own and hold the number.
Heat treat behaves differently from a coating in a way that matters for the arithmetic. A coating lands on a surface, so a bore and an outside diameter move in opposite directions. A part through a furnace scales, so the bore and the outside diameter move the same way as each other, and which way that is depends on the metallurgy rather than on the geometry.
The practical answer for anything tight is that it does not come off the furnace to size. Leave grind stock, heat treat, then grind, and the growth becomes something the grinder removes rather than something the tolerance has to absorb.
| On the print | .4990 / .5010 in |
|---|---|
| Process | Heat treat |
| Per side | 0.002 in |
| The dimension gets | larger at this operation |
| Pitch diameter shift per unit of per-side effect | 2 times |
| Hold before the process | .4950 / .4970 in |
Open this case in the calculator, and change the numbers.
Computed by ctrlPlanner. MIL-STD-870, Federal Screw Thread Specification H28.