some can be hard to get of they have small grub screw, some models the grub screw is peened over and has to be drilled to uncover screw ,screw can be od sizes to, put some rost off or some type of penetrative oil in the screw hole after taking grub screw out and in the other three slider cover holes then use compresed air to push the oil into the threads the alloy bottoms can gaul on to the chrome sliders if you dont lube them and use some heat .we have the tool to put on the chrome sliders goes through the two holes and the alloy lowers in the vice