Abstract: A hot top assembly for an ingot mould includes a number of side boards which line the walls of the mould, leaving at each corner of the mould a gap which tapers downwardly in width between the edges of two of the side boards, each of these gaps receiving a wedge member constituted by a plate which tapers downwardly in width and has at its downwardly extending edges integral margins shaped to engage both the end surfaces and the inner surfaces of the side boards. The two marginal portions of the wedge member are divided transversely into separate flanges, each extending over only part of the length of the wedge member, some of these flanges projecting forwardly from the central plate portion of the member, while the remainder project rearwardly therefrom. The two flanges or sets of flanges at each edge of the wedge member lying at such an angle to one another that they receive and locate the corresponding side board and the assembly is held firmly in position in the ingot mould.