This part’s original, Radius part number 433. A Radius catalogue from the 1920’s provides this sectioned illustration of their silent burner, available in two sizes but part no.433 fits both. With no original burner, I decided to adapt a Primus No.4 stove’s silent burner. The finished result. Primus No.4 on the right, my Svea No.40 with the UFO burner fitted, left. The burner skirt/shroud is wider and deeper on a No.4 burner, so in this photo I reduced the height of it. Later, I re-formed it (anneal/bend up a little/anneal and so on) until it was not so broad or shallow. The No.4 burner on the right has a burner riser spigot that has too large a diameter for the Radius to fit, so an initial adaptation was to silbraze a tube of lesser diameter in place in the altered burner. With the No.4’s jet nipple (0.23mm orifice diameter) there was overfuelling. I used my hypodermic needle insert method to reduce a 0.32mm jet to 0.18mm and that gives good combustion John
