The manufacture of a casing which has a boss includes providing two canister portions a first defining an outer wall geometry of a casing including a boss and a second defining an inner wall geometry of the casing. The casing is made using known PHIP methods. The second canister portion includes an array of holes or recesses which, when the canister portions are aligned, face a recess on the first canister portion which defines the boss such that in the nett shape COS an array of pedestals is provided aligned with the boss. The dimension from an exposed end of a pedestal to an exposed surface of the boss is sufficient to receive a bolt thread of the minimum length required to secure a component to the boss.