Ed, my er25 collet set has 14 collets from 1/16 to 5/8". I use the 1/16" to clamp a #55 drill for detents. I use them for all my folder drill sizes #55 through #41. The 1/8" will grip the 30 and 31. Not saying all drills will fit, but the only one I've tried that wouldn't is a 9/64. I use...