If you want the best possible fletching to shaft fit, file the clamp down to fit the shaft. A 10" half round bastard file works very well, simply place a shaft in the jig and eye ball the clamp against it. Shine a flashlight behind the clamp/shaft surface to see the gap. File the clamp down, checking the fit as you go. It really is an easy process as the clamps are aluminum and file down very easily. The clamp for my 11/32" wooden shafts needed a small ammount of metal removed, the one for "skinny carbons" such as my Beman MFX shafts require a little more removal but the finished clamps do a beautiful job.