Abstract: An improved combustion chamber comprises a shell having a circular array of integral teeth formed at one end thereof. Shrunkfit onto said shell end at or near the roots of the teeth is a ring. The toothed end of the shell is received in an opening in a sheet header so that the ring engages against the header sheet and a continuous weld bead is formed between the ring and the header sheet all around the shell. The shell teeth are bent radially outward and engage the header sheet on the opposite side thereof from the ring so as to be in intimate thermal heat exchange contact with the sheet and these teeth are also welded to the header sheet. The aforesaid engagement between the chamber and rear head minimizes stresses on hot end of the chamber and prolong its useful life. Means engaged around the opposite end of the shell supports, and yet permits lengthwise movement of, that end of the shell.