Screw Threads of Stay Tubes
||Stay tubes shall be screwed
at both ends with continuous threads, and the holes in
the tube plates shall be tapped with continuous threads.
The pitch of the threads shall not be finer than 11 threads
per inch. The stay tubes shall be expanded by roller expanders
and not made tight by caulking only.
||Stay tubes may be attached
by welding in which case they shall not be adjacent within
the same tube next except in local areas, where not more
than two adjacent stay tubes may be attached by welding.
The form of attachment shall be such that there is a mechanical
hold in addition to the welding, as shown in Figure
On completion of welding the stay tubes shall be lightly