The Sorby Half Radius Cutting Tip is another in their extensive line up of special tips for placing various details on small projects. It fits on to handle and shaft sets of the Mushroom Tool (#88905), Box Hollower (#88903), and Captive Ring Tool (#63081), so once you have any of those tools the possibilities really open up. Tip has a width of 1/2". High Speed Steel (HSS). England.