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- Input the following parameters per your preferences
- Desired factor of safety
- Shear strength or yield stress for tapped material (note that the calculations are designed to be used with shear strength, but a wise person would use the yield stress instead)
- Tensile Strength of Bolts
- The expected load to be spread across all bolts
- This is purely a tensile load (ie: the force that rips a bolt out of its threads), the bolts should not be in shear
- This assumes that the load is distributed evenly across all bolts
- This number is a total, not the individual force experienced by each bolt
- The bolt's major diameter
- The bolt's minor diameter
- The bolt's pitch diameter
- The threads per inch
- By running the script, the program will output 4 values
- The minimum number of bolts
- An original calculation is done, and then a function is applied so that the returned value is both even and slightly overshot
- 2 Two different calculations for length of engagement (the length of threads under shear)
- The differences between the two is the method of calculating shear area. The first calculation is simpler and generally more conservative, while the second is more complicated and accurate
- A recommended standard length of engagement to go with
- The minimum number of bolts
- Important assumptions
- There is negligible shear stress on the bolts
- The tapped material is softer than the bolt itself
- The tap and especially the clearance hole are done correctly
- The bolts are not over tightened
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