How about 50% of them? If the lumber you use isn`t straight, you need a BoWrench deck clamp - the easiest and fastest way to straighten an onery board I have ever seen. To use it, just place one end of the BoWrench over a joist, snug the clamp against the board to be moved, and pull the handle. The unique clamping action holds the board in position so that you can use both hands to screw it down. Measures about 24" long, suitable for use on all 2x (1-1/2") or smaller joists. Use the optional adjustable gripper when working with joists up to 6-1/2" thick. Tongue and groove blocks protect the edges of T&G flooring and plywood. Made in the USA.