CBN Flywheel Grinding Wheels Goodson's CBN Flywheel Grinding Wheels features an abrasive that sheds easily to keep wheel cutting clean. The wheels are made of an aluminum core, 1'#8260;8" thick CBN material with a 1-1'#8260;4" arbor. Sizes in diameter include: 2", 2-1'#8260;4", 2-1'#8260;2", 3", 4" and 6".