Abstract: A clamp device to hold building trusses in place after the trusses have been deposited upon a building foundation by a crane and while they are being nailed to stabilize their position prior to application of building panels thereto include a pair of substantially identical first U-shaped strip members positioned spaced apart parallel to one another with lateral portions at each end being aligned with each other. Spaced apart cross-ties fix the first members in such position and a second U-shaped strip member similar in configuration to the first members is captured between the first members by the cross-ties to move parallel thereto with lateral portions of the second member projecting from the same side of the device as the lateral portions of the first members. A levered cam unit effects relative, parallel movement between the first and second members to clamp and unclamp the device to building trusses.