We've created the smallest guide bearings in the industry!, If you've Often wanted to trim and shape small details in tight corners, but were disappointed by the scoring and burning left behind by solid pilot bits, we've got what you've been looking for: eight of the most commonly used profiles In miniature sizes – Complete with tiny miniature ball bearing guides. These bits are perfect for small fine work such as signs, lettering, small boxes, guitarmaking/luthier and toymaking; essentially any project that requires tiny flush trimming or shaping. Don't let the small size fool you; these bits are precisely machined and carbide-tipped., #MRR108, diameter (D): 5/16, radius (r): 1/16, cutting Height (B): 5/16, shank (D): 1/4, overall length (L): 1-13/16, replacement bearing: 47775, flutes: 2, D1: 3/16, MRR108 carbide Tipped miniature corner Rounding 1/16 radius x 5/16 dia x 5/16 x 1/4 inch Shank with mini 3/16 dia lower ball bearing