Tapping Formulas
| RPM = (SFM x 3.82) divided by D | D = Diameter of Tap in inches |
| SFM = (3.14 x D x RPM) divided by 12 | D = Diameter of Tap in inches |
| Inch Taps Drill Size = Major Diameter of Tap minus |
.01299 x % of Full Thread
# Of Threads / inch |
| Inch Taps % of Full Thread = Threads/in x |
Major Dia. of Tap minus Drill Diameter
.01299 |
| Metric Taps Drill Size = Major Diameter of Tap (mm) minus |
% of Thread x Metric Pitch
76.98 |
| Metric Taps % of Full Thread = |
76.980
Metric Pitch |
x (Basic Major Diameter (mm) minus Drilled Hole (mm))
|
| Form Tap Drill Size = Basic Tap OD |
minus
|
.0068 x % of Threads
Threads / Inch |
| Inch Taps IPM (For Threads) = RPM divided by TPI (Threads per Inch) |
| Inch Taps IPR (For Threads) = 1 divided by TPI |
| Inch Taps IPM (Inches Per Minute) = IPR x RPM |
| Inch Taps IPR (Inches Per Rev.) = IPM divided by RPM |
| Metric Taps MM/Min = RPM x Metric Pitch |
| Inch Taps In/Min = RPM divided by # of Threads / in. |
| Distance = Rate x Time |
| Time = |
Distance
Rate |