You can spot a simple unidimensional bow in a blade by sighting down the leading and/or trailing edge.

To find a twist, first set both blade grips STATICALLY to the same pitch by matching all control rods. Next mount up the blades and pick a side from which to start. Beginning at the root of one blade, use your pitch gauge and measure pitch at the root, midblade and at the tip. It makes no difference what the numbers are; they should be consistent if the blade is twist free and NOT of a washout design. Flip around to the other blade and repeat the measurements. The numbers you get should pretty well mirror the ones from the first side. If the pitch readings are consistent across the blade yet different from the first side, the blade reinforcements are on differently.

Given the fact that a decent set of glass blades can be had for about $80, and you can't trust that the wood baldes you have are good (plus the flying time you're losing screwing around with this stuff), you can see why so many guys just don't bother with wood blades anymore.

Ben Minor