This wedge jack is a larger version with upgraded parts for large area print beds. It should be printed with a higher heat resistant material since it will remain in contact with the bottom of a heated print bed.
Parts need to put this together were all purchased from Lowes:
(x1) 6" 10-24 Threaded Rod
(x2) 10-24 Coupling Nut
(x2) 10-24 Nut
(x1) 10-24 x 1/2 Clamping Knob w/Male Stud
My Creality CR-10 S4 has a bow of maybe 3mm or 4mm in the middle of the print bed. I struggled for over a month to come up with a solution to make the bed level in the middle but it just wouldn't happen. I opted for the cheapest way possible and this is the solution I came up with.
After you print all the parts you may want to grease up the channel and the threads of the screw. This will drastically reduce binding as the nut slides through the channel. The 2 nuts on both ends are super glued on. Be sure all parts are exactly where they need to be and the Wedge works as advertised prior to super gluing the parts