The Amana 61297  cutterhead features lightweight aluminum alloy construction with precision ground, micrograin carbide knives. It also features a unique and positive locking system to hold the knives, which ensures exact indexing, less down-time and more production. Features two-sided replaceable carbide knives. Manufactured to strict 'BG' specifications, which limits the chip thickness for a safer, more controlled cut. Standard bore is 1-1/4". Includes 3mm T-handle hex key. This cutter has a  120mm diameter.  The 61296 is slightly smaller.  It has a 90mm OD.