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Torsional & Axial Deflection
Posted August 22, 2019 - Updated Mar 24, 2020
What is a Torsional & Axial Deflection? Screw torsional deflection (sometimes called “windup”) may occur when loads are high (resulting in high drive torques) and when the screw is long. Also, screw axial deflection caused by high compression or tension loads may be significant when loads are high and the screw is slender. When rotation […]
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Horizontal Bending
Posted August 22, 2019 - Updated Dec 3, 2019
Horizontal Bending Basics Long screws mounted horizontally may sag due to the weight of the screw. If the sag is significant, the screw threads will be compressed on the top section of the screw and extended on the bottom section of the screw. In severe cases, the nut may actually seize on the screw as […]
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Column Loading
Posted August 22, 2019 - Updated Dec 12, 2019
Column Loading Basics Screws which are loaded in compression may be so slender (long in relation to diameter) that they can fail by elastic instability (buckling) much before they reach their static load limit or compressive strength. A screw system design which undergoes a compressive load must be checked for safe column loading. Basic safe […]
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Screw Backdriving Efficiency
Posted August 22, 2019 - Updated Dec 12, 2019
Efficiency and Backdriving The mechanical efficiency of screw drive systems is often confusing. This is because unlike most power transmission components, V-belts, sheaves, timing belts, chain drives, and gear systems (with the notable exception of worm gear systems), screw drive systems actually exhibit two efficiencies – one in the drive direction (torque to thrust conversion) […]
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Application Engineering: Speed
Posted August 22, 2019 - Updated Dec 3, 2019
Speed Basics Linear speed is dictated by the functional requirements of the application. Rotational speed is a function of the linear speed and the lead of the screw. Rotational speed (rpm) is equal to the linear speed (in./minute) divided by the lead of the screw (in./rev.). Leads are listed in the Screw/Nut Engineering Data for […]
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Screw Actions
Posted August 22, 2019 - Updated Dec 3, 2019
The primary concern in any screw and nut system is the amount of load to be moved. The load must be determined by the designer before the proper type and size of screw can be selected. If the load is to be moved vertically, the nut load is equal to the weight to be moved […]