I created and tested this guitar fretboard radius sanding block and was so happy with the result! I've uploaded versions of the file at all common radii and the flat top makes them great for clamping to apply even pressure across the radiused fretboard as well. All these models are 12 inches long, but you can scale them along one axis only in your slicer to make them whatever length you want. Print them standing up on their end for best results.