Just bought this 200P which I think is great, having both a fuel-gauge and a pressure-gauge. Nice and compact too, so instead of giving it a strip and clean I've left it as it came and I've been using it as my main outdoor lamp. One of the minor things to sort out is the pressure gauge - I noticed the needle was sticking. This was caused by the cover being pushed onto it beacuse of the 2 missing screws. There was a small piece of screw inside one of the threads which I've managed to remove and measure at 1.54mm thread diameter, but the thread pitch looks more like 0.5 so it can't be an M1.6. Anyone know what size they are? Thanks Trevor
The odds are it is actually a whitworth thread. With those dimmensions it could be a 1/16" W which equates to 1.588 mm and a pitch of 0.423 mm. You find a lot of whitworth based threads on Swedish lamps.
Thanks for that Nils. There was only enough of the screw left to measure 2 or 3 threads, so it probably is 0.423. If they are 1/16" they may be hard to get hold of now. I've had a look on the internet, ebay etc. and even went to a couple of local nut/bolt specialists. Might just have to use some small BA's and retap the holes accordingly. I guess the lamp is from the early 60's, I'm surprised Sweden was still using BSW then and I notice the gauge is calibrated in metric. Cheers Trevor
The lantern could be from the 50s or 60s, but my guess would be the 60s. I've often wondered why the swedes used whitworth threads so much, but you see them a lot. Primus even made their own with metric diameters and whitworth thread pitch. As for whitworth threads in relatively modern lamps. The original design was from the 30s so why change. Makes it easier as far as spares go.
I've come across some strange threads in my time, but metric dia and whitworth threads !!! That takes the biscuit
A good example is the jet for the Primus 1020. It is 7mm in diameter but with 35 threads per inch in a whitworth pitch. Doesn't match anything. Of course with Primus being part of the Bahco concern, it was no problem making tools for any thread. Then they knew that customers would have to buy genuine Primus parts.
