Jackscrew
![A 2.5-ton screw jack. The jack is operated by inserting the bar (visible lower left) in the holes at the top and turning.](/Images/godic/202501/21/House_Jack_2.5_tons5530.jpg")
![A jackscrew operates this automotive scissor jack.](/Images/godic/202501/21/Jackscrew5530.gif")
![Antique locomotive screw jack](/Images/godic/202501/21/Antique_jack5530.jpg")
![Antique wooden jackscrew for repair of cart and wagon wheels (Ethnographic Museum of Elhovo, Bulgaria)](/Images/godic/202501/21/WoodenJacs5530.jpg")
A jackscrew is a type of jack that is operated by turning a leadscrew. In the form of a screw jack it is commonly used to lift moderately heavy weights, such as vehicles. More commonly it is used as an adjustable support for heavy loads, such as the foundations of houses, or large vehicles. These can support a heavy load, but not lift it.