Union Adapters Unions are available in either model tapered pipe (MTP) threads or solder socket (SS). Show All Products * New Items * 20 Ton Shay Package Angle Valves Boiler Check Valves BOILER GROUP CASTINGS Bushings Caps/Plugs Check Valves Displacement DRAWINGS AND MISCELLANEOUS GROUP Elbows ENGINE GROUP CASTINGS FRAME GROUP CASTINGS Gas Burners and Accessories Globe Valves Lubrication Materials Mechanical Miscellaneous Miscellaneous Parts and Castings Nipples Pressure Gauges Safety Valves Specialty Valves Tenders Tools TRUCK GROUP CASTINGS Union Adapters Unions Water Gauges Whistles Union Adapter, 1/4-40 MTP (M) – 1/4-40 MTP (F)$7.00 Union Adapter, 1/4-40 MTP (M) – 1/4 Solder Socket (F)$7.00 Union Adapter, 1/4-40 MTP (M) – 3/16 Solder Socket$7.00 Union Adapter, 1/8 NPT (M) – 5/16-27 MTP (F)$9.00 Union Adapter, 1/8 NPT (M) – 5/16 Solder Socket (F)$9.00 Union Adapter, 5/16-27 (M) MTP – 1/4-40 (F) MTP$8.00 Union Adapter, 5/16-27(M) MTP – 1/4 Solder Socket (F)$8.00 Union Adapter, 5/16-27 MTP (M) – 5/16 MTP (F)$8.00 Union Adapter, 5/16-27 MTP (M) – 5/16 Solder Socket$8.00 Union Adapter, 1/4-40 MTP (M) – 3/16-40 MTP (F)$7.00