forms slid down and out of the way so the cast concrete panel may be cut and removed from the bed it should be readily apparent that the side forms may be raised to the fullest extent for casting panels having a greater thickness and may be dropped partially if the concrete panel to be cast has a lower overall thickness the invention works for either the moving casting bed machines as shown or for stationary beds in both cases less width is required for the casting operation and varying product thicknesses may be readily handled by simply adjusting the side form 16 heights with the hydraulic mechanism 40 the hydraulic mechanism 40 may be controlled by a controller represented by a control box 54 as is known in controlling hydraulics of course while shown with a hydraulic system any form of motive power may be used to raise and lower the side forms the side form 16 may benefit from an additional member that locks the side form at its desired height to counter the forces of the weight of concrete held within bolts 60 may be placed along the length of the bed that can secure the side forms to the bed after the height has been set alternatively additional holding power may be provided with electromagnets which allows the side forms to have an on and off control of the additional resistance to outward.