Screw jacks are a class of jack that work by applying tension to a leadscrew. A screw jack is typically self-locking, unlike a hydraulic jack, which requires constant pressure to stay in a locked position. There are many different applications for screw jacks, including as automotive jacks and in the construction industry. Small screw jacks are relatively simple to build, and the materials used are usually inexpensive.
Things You'll Need
- Steel plate
- 2-inch steel pipe
- Cutting torch
- Bolt, 6 inches long by 1 inch wide
- Welding rig
Cut three square pieces from the steel plate using a cutting torch. Each square should be four-inches across. Weld the pipe onto one of the squares. This will serve as the base plate of the screw jack and prevent it from tipping. Drill a hole slightly larger than the diameter of the bolt into the second steel square. This will form the cap plate.
Thread the nut onto the bolt. Insert the bolt into the open end of the pipe. Slide the cap plate over the head of the bolt. Weld the cap plate to the pipe. Make sure that the nut and bolt assembly remain free. The nut should rest on the cap plate, but must remain free to turn.
Weld the third steel square onto the head of the bolt. Use a wrench to turn the nut, and the top plate of the screw jack will rise. The threads on the bolt will lock it into place. Turn the wrench in the other direction to lower the jack again.
Tips & Warnings
- Welding is required for this project. Do not attempt to weld unless you have experience.
- Be extremely careful when using any jack. An improperly balanced load can slip, causing injury or property damage.
- Photo Credit Jupiterimages/Photos.com/Getty Images
Screw Jack Calculations
A screw jack, or jackscrew, is a jack that derives its compressive force from the turning of a leadscrew. A self-locking trapezoidal...
How to Make a Jack-o'-Lantern
The beauty of carving your own jack-o'-lantern is that there are no set rules for the design. From cute to scary and...
How to Build a Rocking Chair
There is nothing quite so relaxing as sitting in a rocking chair and rocking after a tough day. Did you ever wish...
How to Replace Hydraulic Oil in a Floor Jack
When it comes to lifting a heavy object at home such as a car, camper, trailer or lawn tractor, many homeowners turn...
How to Build a Boot Jack
As people grow older, it becomes more difficult to remove shoes properly -- especially if they are cowboy boots. It can be...
How to Jack and Block a Sagging Floor
Sagging floors are a common ailment in older homes. In some cases, foundations have settled. In others, old framing timber has given...
How to Jack Up a Ceiling Joist
Jacking up a ceiling joist or beam is a process that requires the use of a screw jack. When a floor in...