Mystery threads on Optimus 930/300cp upper vapourisor? I found my Optimus at a nearby auction recently. As it were, the upper vapourisor (part#2610) was missing. I contacted FOGAS, but the part was discontinued/not available. Their suggestion was to try to get hold of another lamp and get spare parts from that. Apparently, early 200P:s were fitted with the same vapouriser but were later fitted with a larger loop (70mm) version which does not fit the 930. When asked for specific dimensions of the vapouriser, they replied: "Loop diameter 65mm, height 110mm, tube diameter 8mm, thread size bottom attachment W12.2*26 and top jet attachment W7*24" and that's where they lost me... Despite some thorough Googleing, I haven't managed to understand the thread size references above. Now, can anyone help me "convert" or interpret please? If I cannot find a spare #2610 somewhere, I'm considering refitting/re-threading a similar one (if possible?) and need to know which correct threading tools to use. Regards//Erik
The jet thread is the standard type used on all Optimus lamps. It is 7 mm diameter with 24 threads per inch in a Whitworth profile. I have never measured the thread for the attachment between the upper and lower vapouriser, but from what is written above it must be 12.2 mm diameter with 26 threads per inch Whitworth profile. This should also be a standard Optimus thread for many other models. I am not sure an Optimus 200P vapouriser can be modified to fit, but it would be the closest in size.
There is a 1/2" x 26 TPI Whitform (a model engineer's thread) but 1/2 inch is 12.7mm. There are also other 26TPI threads such as cycle and brass. Without thread guages I think you are at the mercy of somebody who actually knows what it is. Not to get confused with BSW (British Standard Whitworth) is quite a coarse thread. You should be able to measure the diameter of the lower part that you do have to confim/deny the 12.2mm ? Chris
Thanks Nils, I suspected as much, but the 12.2 does confuse me still. Perhaps Fogas made a writing mistake and wrote 12.2 instead of 12.7? I'll doublecheck. //Erik
There are a lot of threads used by the Swedish manufacturers that are not standard. Primus is the best (worst) example of this. Usually they used a metric diameter but with a non standard Whitworth thread pitch. Therefore 12.2 is quite possible, but worth checking.
Indeed ... I asked Fogas again and they reconfirmed by quoting "W12.2 H12 26ggr" (usual abbreviation for 26 times, but possibly for 26 threads here). I'll keep checking and if anyone has a spare vapourizer #2610/65mm loop, you know where to find me Cheers/E
Not surprising. It is not unusual for the lantern makers to use non-standard sizes, threadforms or combinations of them. I cannot conclude but it seems to me that:- as long as its not the tap or die size that a person can buy from the general hardware store, we'll take it as a candidate. I'm sure there are manufacturer's reasons for them to be made as such. As what Nils pointed out, combination of metric diametres with the Whitworth thread profile was a favourite. In many instances, you would have to customize it. If you can't find the original spare parts, the machine shop is the only option to re-produce the odd thread sizes.
I have never compared thread types with Willis/Bates but perhaps I should as there was involvement long ago?
Perhaps, i have noticed, at least that the petromax rapid-starter port can be blocked off lovely with1/8" B.s.p. blanking plugs and that the petromax burner nozzle/mixing chamber is fine with 3/4" B.s.p. fittings...i assume that this phenonemon is a relic of Gas Lighting and Gas supply threads having been standardised way "back in the day"....The I.C.G.A. which exported Gas-lighting to Germany in the 1840's? was still Maintaining Berlin's lighting till the First World War, then becoming Bamag....perhaps to innovators like Max Graetz, readily available nozzles and brassware,taps dies etc...caused this effect. (this is a hypothesis of mine, perhaps someone here has more a more accurate or possible account to give) I imagine that some other European countries also experienced this phenomenon...B.s.p. thread Tap sizes seem Industry standard to me for water etc, in spite of metrification. I notice a phenomenon too with the American N.P.T. pipe sizes, that they seem to be industry standard for Refrigeration and Air Conditioning equipment. Blessings, RxR
