Directions
This calculator is designed to resemble a spreadsheet calculator that can be printed as a report for project recordkeeping. The term project, with regards to Precision Mindset calculators, refers to engineered designs, homework problems, tutorial problems, hobby designs or self-study.
Cells with a border are inputs and cells without a border are outputs. An external thread refers to a bolt, screw, or threaded rod. An internal thread refers to a nut or tapped hole.
- Select the appropriate thread designation from the dropdown menu or leave it as User Defined and enter values for the basic diameter and pitch.
- Select the calculate button to complete the analysis.
- Print a report for your project recordkeeping by pressing the print button.
Assumptions
- The thread profile is for an ISO metric screw.
Equations
- Height of the Fundamental Triangle
$$H = \frac{\sqrt{3}}{2}p$$
- External Thread Clearance Height
$$h_1 = \frac{H}{4}$$
- Truncated Thread Height
$$h_2 = \frac{5}{8}H$$
- Internal Thread Clearance Height
$$h_3 = \frac{H}{8}$$
- External Thread Clearance Diameter
$$d_0 = d-\frac{7}{8}H$$
- Minor Diameter
$$d_1 = d-2\cdot h_2$$
- Pitch Diameter
$$d_2 = d-\frac{3}{4}H = d-\frac{3}{8}\sqrt{3}\cdot p$$
- Internal Thread Clearance Diameter
$$d_3 = d+\frac{H}{4}$$
- Crest Width
$$f_1 = \frac{p}{8}$$
- Root Width
$$f_2 = \frac{p}{4}$$
- Base Width
$$w_1 = \frac{3}{4}p$$
- Pitch Diameter Width
$$w_2 = \frac{p}{2}$$
- Thread Arc Length per Revolution at d1
$$s_1 = \sqrt{\left(\pi d_1\right)^2+p^2}$$
- Thread Arc Length per Revolution at d2
$$s_2 = \sqrt{\left(\pi d_2\right)^2+p^2}$$
- Thread Arc Length per Revolution at d3
$$s_3 = \sqrt{\left(\pi d_3\right)^2+p^2}$$
- Nominal Diameter Area
$$A_d = \frac{\pi}{4}d^2$$
- Root Diameter, d0 Area
$$A_r = \frac{\pi}{4}d_0^2$$
- Thread Shear Area per Revolution at d1
$$A_{s,1} = s_1\cdot w_1$$
- Thread Shear Area per Revolution at d1
$$A_{s,2} = s_2 \cdot w_2$$
- Thread Shear Area per Revolution at d1
$$A_{s,3} = s_3 \cdot w_1$$
- Tensile Stress Area
$$A_t = \frac{\pi}{4}\left(\frac{d_2+d_1-\frac{H}{6}}{2}\right)^2$$
Background
