Posted on August 1, 2022March 24, 2023 by Dale Phillips Conical Radius Fretboard Formula Conical Radius Fretboard Formula by Elaine Hartstein Originally published in American Lutherie #34, 1993 and Big Red Book of American Lutherie Volume Three, 2004 As a follow-up to Tim Earls’ article “In Search of the Perfect Cone” in American Lutherie #30, I’ve come up with a formula for finding the hypothetically-ideal radius for the fingerboard at any distance from the nut. Since a set of nonparallel strings cannot lie flat on a cylindrical fretboard, we wish to discover the geometry of the cone described by the strings. As Tim Olsen suggested, the outside strings (as opposed to the edges of the fingerboard) should define the cone. The cone defined by the fingerboard edge would give results with a smaller radius. Become A Member to Continue Reading This Article This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. If you are already a member, login for access or contact us to setup your account.