Hi, It is a fairly common fact that the lipstick burners off British and Swedish stoves are not interchangeable. They have different threads (reported to be UNC and Whitworth respectively) and although British lipsticks will fit British and Swedish ½ pint stoves, the Swedish lipsticks will not fit on British ½ pint stoves (scroll down here). The threads must be different, but I cannot measure the threads accurately enough to tell if one is UNC and the other Whitworth. However while making my own lipstick burners I stumbled on a thread form that will fit the threaded burner boss on both Swedish and British stoves, so now when I make lipstick burners I can used one thread for both British and Swedish stoves. The thread form in metric has a 16mm OD, a 1.25mm pitch and a 55 degree angle. The 55 degree angle is the same as used on Whitworth threads and provides a deeper thread depth than the 60 angle for the UNC. Here are some pictures where I used solid aluminium bar for the demonstration. The solid aluminium bar bottoms out on the lead washers after two to three thread turns, but the thread fits both stoves comfortably, it can be finger tightened with no slop. The two tanks used (Primus on the left) are in good condition and do not have worn threads. When I finish the prototype 'universal' lipstick I am making, I can hopefully post some pictures of it in use on both tanks.
Following with interest as I'm in need of a British lipstick. A project that is currently well down on the round tuit list.
