I recently acquired another Lamb stove. This time an early model with a circular finger grip, no safety valve/pin, and a conventional flame plate burner: I added a stainless steel flame-plate and new seals and then ran the stove. However, the flame pattern is over-rich although it can be made blue by manually raising the flame plate to un-natural levels. The jet apeture was suspect, although I had used an 0.23 mm aperture pricker to clear it on arrival. I didn't have a spare jet, needless to say, but a good Stove-friend carried out one of his famous hypodermic needle transplants on the over-size aperture jet. I have now run this stove with the "new" jet after lowering the flame-plate to a normal level. the flame pattern was much better, with no hint of red. This a relatively rare stove, now approaching its 100th birthday, and it was good to have it performing well again. I will take additional photographs once the weather improves. Best Regards, Kerophile.