After reading all the responses to this question, I was convinced of the benefits and I decided to make my own. Instead of a design with a pointed spindle I decided to make one like a ball valve, but with a hole in a rotating bar rather than a ball. I chose a burner with a lot of thread below the hex nut, as I needed to beef up the nut to provide a platform for the regulator housing. First job was to clean out the inside of the base of the burner so it would accept the steel insert and be clean enough to 'take ' the braze. I achieved this by drilling a slightly larger hole out with a 10mm drill. Then I beefed up the nut by brazing on another cut down nut The insert was cut from 10mm bar, with a 3.2 mm hole in it. and brazed into place. Then a 4mm hole was drilled horizontally through the reinforced nut, and an M6 bolt turned down in the lathe to be a tight fit in this horizontal hole. (You don't need a lathe - you could just braze on 4mm stud on the end of the M6 bolt. This was how I later did the long spindle control shaft). Next job was to drill the 'valve' hole in the end of the spindle using a 2mm drill. If all works according to plan, the burner would be 'off' with the spindle hole horizontal, and 'on' with the spindle hole vertical. A quarter turn total control! Next job was to finish the spindle and to build the housing. The spindle was finished by cutting of the bolt leaving four complete threads, and brazing on a long 4mm control shaft using Silverflo 20. The housing was made from three different diameter brass and copper tubes brazed together with a M6 nut brazed in the fat end, and a M8 thread formed in the other end. The tubes and nut were brazed with high temperature Silverflo 20 filler, and after threading the spindle into the housing and fitting it all into the burner, the housing was brazed into place using the lower temperature Silverflo 55 so that the previous braze joints didn't remelt. The spindle was only threaded in place temporarily to correctly align the housing around the hole in the burner nut, so before the final braze the spindle end and the threads in the nut and on the spindle were coated with permanent marker ink so that the braze didn't stick to them, and I could remove the spindle afterwards. Next the spindle bits were assembled to fit together. Two washers each end of a roll of graphite sheet and a short M8 bolt with a 4mm hole through it. All fitted into place and tightened up. The stove works OK, and simmers (sort of). There is not much control (1/4 turn max), so it is a delicate balance between low simmer and out! It works well enough for me to appreciate some of the features and benefits of a regulated burner. Best feature is being able to simmer and then go back to full power without pumping. In case you are wondering about the 'engine room'. It is an old trusted Monitor that I use for testing burners, and for heating my Kubex oven. I cut the legs off so it fits under a variety of pot stands, but kept the legs for when it is on coffee duty. I know, I should get out more.