Loctite 660 Quick Metal 50ml Tube 660-050ML/LOCTITELOCTITE 660 is a high strength retaining compound with good gap filling properties, ideal for repairing worn out seats, keys, splines, bearings or tapers without remachining. LOCTITE 660 is designed for the bonding of cylindrical fitting parts, particularly where bond gaps occurs without the need for remachining. The product cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage due to shock