Although this might not strictly apply to your situation, it may be applicable (you decide). If nothing else this formula may be of use to others in that you can use it to create frames, combings, etc. that are more accurate.

An article on bent laminations (FWW #115, pp. 70-75), I'm offering a way of determining the degree of springback after the lamination is removed from the form. I became interested in this problem when I made a pair of chairs from reclaimed teak. The curved members of the seat and back were laminated from stock about 1/4 in. thick. I needed to determine in advance the amount the lamination would spring back when the clamps were released.

I discovered that for many situations, a delightfully

simple solution followed from the application of

beam-bending theory, as illustrated in the drawing.

A number of plies of similar wood (n) are glued

and clamped to a curved form, which is shaped to

give the lamination a deflection of "x." When the

clamps are removed, the lamination springs away

from the form by an amount "y." Exactly how

much springback can be predicted with the

formula y = x/n2.

The ratio of springback to the original deflection

depends only on the number of laminations. The

ratio does not depend on the properties or

thickness of the wood or the geometry of the

curved form. Thus, for two plies, the springback is

one-quarter of the initial deflection, or one-ninth

for three plies and one-sixteenth for four plies.

--Bill Clayden, Isle of Wight, England