Jackscrews:
Where you have an item such as a spectacle plate between flange there is often a need to periodically remove and reverse the plate. In order to remove the plate the flanges need to be separated. In larger pipes there is little "spring" in the pipe so extra holes are drilled & tapped into one of the flanges and screws are inserted. When the plate requires removal the screws are turned to force the flanges apart, thus easing the plate removal.
Jackscrews:
Where you have an item such as a spectacle plate between flange there is often a need to periodically remove and reverse the plate. In order to remove the plate the flanges need to be separated. In larger pipes there is little "spring" in the pipe so extra holes are drilled & tapped into one of the flanges and screws are inserted. When the plate requires removal the screws are turned to force the flanges apart, thus easing the plate removal.
