How to Calculate the Efficiency of Screws
The efficiency of a screw is a ratio measurement of work output to work input, and is expressed as a percentage. The efficiency is an important measurement to know, as it will foretell how reliable, durable and sustainable the screw will be when secured to various materials. Efficiencies vary based upon the size, type and manufacturer. To calculate the efficiency of the screw type you are using, you will need to know the screw PD, the size of the screw lead and the friction coefficient. This information should be provided and labeled on the packaging for the screws. Does this Spark an idea?
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Things You'll Need
- Paper, pen
- Screws
- Screw pitch diameter measurement
- Screw lead measurement
- Friction coefficient value
Instructions
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Write down the screw pitch diameter, screw lead and friction coefficient measurements and values for the screw.
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Go on the Internet to use the calculator on RACO International's website. Click on the top bar, and click on the “Screw Efficiency” radio button. The Lead Screw Efficiency calculator will appear.
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Select and enter the type of directional application you will use for the screw in the radio button. Your choices are for a horizontal or vertical upward movement, or for a vertical downward motion.
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Enter the screw pitch diameter value in millimeters or inches in the box for “Screw PD.” The pitch diameter of a screw is the diameter at which the thread thickness and the thread space are equal. The calculator can convert millimeters to inches, and vice versa.
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Go to the second line and enter the screw lead value in box for “Screw Lead.” The lead is the axial distance that the nut must advance in one revolution of the screw. Use inches or millimeters, and the calculator will make conversions.
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Move to the third line and enter the friction coefficient value in the box for “Friction Coeff,” with the corresponding value for your screw. The friction coefficient is a measurement for the resistance to motion of a screw, and varies depending on whether the screw is lubricated; the type of material the screw is applied to, the threads, pressure and more. For example, the friction coefficient for a steel on steel application might be 0.80, while the friction for an application of a lubricated steel screw on wood might be 0.20. You can refer to a chart for friction coefficients.
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Click “Calculate.” The software calculator will immediately provide you with the efficiency percentage for your screw in the box for “Efficiency.”
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Tips & Warnings
If you do not have access to the measurements, contact the manufacturer to obtain the corresponding measurements and values.
References
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