Hate to show my stone age mentality but when you folks refer to the subject item is this flexing the blank to a predetermined amount to check for guide spacing; ie say a casting rod so that the line doesn't touch the blank under a fighting load? If this is what you're talking about how do you determine what amount of load to apply to the blank? Is it something like Load = reel drag set 1/3line test? Is it starting drag load or running drag load ? What about 30pound test braid being used on a casting or spinning rod thats rated for 3/8's to 11/4oz lures and 12-20lb line. Do you consult with the customer on this always or just when in doubt? I have an old stone age method but I'd be embarrassed for you-all to know what it is; that is if we're talking about the same thing. Warren Heck even if we're not talking about the same thing,I'd be embarrassed.

Warren,
C'mon, you can't leave me hanging like this, after all, it's usually the simple ideas that work the best. I promise not to laugh or tell any one else of you method.

You would want to flex it to the maximum amount it was designed for, which is usually a strong 90 degrees. Beyond that the rod was not meant to be fished.

Also I am learning that it is important to flex it or pressure it with a line other than the one you have coming off the reel and through the guides. You need to fasten a line to the tip or somehow hook the tip-top like they did in that article on Rodmaker on the grid layout. That puts the rod in its most natural bend and they you use the line off the reel and move the guides around until you find the point/s where it follows that natural curvature.