The Beco Expanding Set is exactly what you want for use with Beco's Winding Press and Toggle. It includes 12 dyes that range from 27 1/2 to 55 millimeters. Half of these are double concave with an M6 thread inside. The other half contain plain dyes with ten millimeter shafts.  It also comes with 4 replacement O rings. With these dyes you have pretty much any size and shape needed to get the job done. Go to Stuller.com to find the Expanding Set and other great Beco watch tools.