I managed to get my hands on an optimus 1350 lantern, I want to tidy it up but not as new so it can be used regularly. Two issues I have found, 1 See Picture The screw which goes into the centre boss was broken off but the end of it wasn't In the hole, trouble is the boss leaks air. I think I'll have to put a long screw into it to stop it falling inside, then take off the lock nut and put on a copper washer. Can anyone tell me what thread the center screw is? I don't have enough left to measure on the old screw. 2 The "J" tube is clamped by a screw and it has a screw which goes through into the air flow, both are tight and may need drilling out, can anyone tell me if they know where I may buy these screws? The clamp one goes into a kind of clamp shoe. I would appreciate any help with this
Hi thanks Chris, I've been looking on there and trying to use the drawings for the 1200 lamp to find the names they use, then looking up the bits in the list for the 1350 lamp, the center boss is hard to identify, but i may put in a new mixer tube and air screw, then try and recover the old one at leasure. I just wondered if anyone with a 1350 may have measured that center screw which is sheared in the picture, hopefully i could try and improvise one.
@rayw The centre screw thread is 3/16 X 24 BSW. I couldn't see an Optimus one on the base-camp site but a Petromax one (reference no. 14 fits BUT it will need shortening by 5 or 6 mm.). Optimus at top, To fix the leak at the centre boss, clean the area inside and out to remove all traces of fuel. I used my Dremel with a thin grinding disc to get through the plating to bare brass where the hex nut meets the tank before suspending the tank by the centre screw and heating the boss until the solder ran and added a little more for good measure. Have you tried heat & quench to try and free the two seized screws ? 50/50 acetone/ automatic transmision fluid is a good penetrant used by some of us here, @presscall recommends a Plusgas product but I forget its exact name. If you can adust the "air mixing screw" so that the paddle is vertical, then all well and good. If it needs to be replaced, item No. 2722/1 is available from base-camp. I couldn't see "mixing tube clamp screw" but perhaps you could make your own 13mm long grub screw from an M6 x 1 bolt.
Henry Wow, you seem to have covered the whole story, many thanks for your help, I should be able to get moving on this again soon. I am surprised that the thread is whitworth, I was thinking they would have used metric, but it obviously wasn't when I tested it, and the broken screw didn't have enough threads to get the thread gauge onto it. I did wonder about leaving the mixer tube and then firing it up a couple of times then see if that would help release the threads.
While the lantern is in pieces, check out the bottom plate with spirit well. The plate is easily distorted by overtightening the centre screw and this distortion has a detrimental effect when preheating with spirits. Compare a distorted plate on the left with a normal one. Fortunately, this is easily corrected by turning the plate upside down and pushing downwards. With the plate the right way up there should be about 5.5 / 6 mm between a straightedge and the plate.
Thanks Henry I have been focusing on my other project but managed to take a look today and it is as you describe, I think it has been over tighten and sheared the clamping bolt, the rim of the bottom plate is also distorted but should be no problem to fix, I am wondering about cutting a brass or copper tube to use as a spacer under the plate which would eliminate this problem forever.
@rayw A spacer would be a good idea but it may take trial and error to determine the ideal length. Too long and there will be free play between frame and tank, too short and you're back to square one. The realisation that a deformed base plate had an adverse effect when preheating with spirit came about when I was fettling simultaneously, an Optimus 550 and Optimus 350. Long story short, when it came to preheating and lighting, both lanterns were troublesome though the 350 flared up much more than the 550. More cleaning of the vapourisers removed what could only be described as, an insignificant amount but it certainly improved the 550. The 350 still misbehaved and I noticed that when preheating, there was a significant flame exiting via the lighting hole. This was wasted heat; why was it happening ? Examination revealed the base plate to be deformed as in the image I posted above. Straighten the plate and problem solved. The lantern now lights easily with a single preheat which is economically advantagious here in the U.K. where methylated spirits / denature alcohol / bio-ethanol is expensive. Bad enough that even when things are working as they should, the 550 and 350 Optimus need twice as much spirit (aproximately 10ml) as, e.g. a Petromax (approx. 5ml). It has been suggested (elsewhere) that this is due in part to the fact that the spirit well is so low down relative to the vapouriser when compared to a spirit cup which sits above the base plate. A fact borne out that by fitting such a cup, a mere 5ml of spirit is all that is needed to successfully preheat 350 and 550 Optimus lanterns.
I received the seals I needed today so did a bit of work, the center boss was very difficult because the locking nut would not turn, could be solder in the threads i dont want to destroy it. I inserted the new screw then suspended the lamp by this screw cleaned the area with solvent then soldered it up adding more solder around the nut, not the most elegant but it seems to work.measured down from the centre plate to the boss using a vernier then measured the distance from the boss to the top of the nut, and aded together, take away 2 mm to give a slight nip and cut my brass tube, add a fibre washer under the retaining screw head. Tried it and its fine now i can nip the screw and it doesn't distort the center plate but holds together fine Just wonder if anyone has a good drawing of the valve on the base of the vaporiser and valve tube assembly ?
The drawing in the user manual is very good : https://classicpressurelamps.com/threads/1959-optimus-550-500cp.6636/ the 550 will be the same/similar as yours.
@rayw you'll see that it's basically the same as the pump N.R.V. What isn't too clear in the drawing in the link posted by @Fireexit1 is the rubber pip may be a moulded affair on the lines of those in a Tilley X246B. Replacements (#2252V) are available from www.base-camp.co.uk for £4.50 or use Petromax #193 @ £1.20 - it worked on my 350.
@rayw Yes - on the 350, 550 and 1550 it has a small brass recess in the centre of the rubber in which the pointed end of the rod sits. (just ike the petromax) like @Henry Plews says you will probably need a new one. I can't imagine the 1350 being different.
Forgive me because I have never worked on one of these before The image is one of the better ones but hard to exactly determine the components inside the NRV, I opened it and wasn’t sure it had been assembled correctly. From top to bottom there is a brass pip which has a rubber insert and a dimple in the centre which has brass in it and the conical tip of the rod coming down from the valve centres in there. Below that there is a spring. Below the spring is a second brass plip which seems to sit on the bottom of the housing, but there is a slot there seems like a screwdriver slot. I the bits I received was a rubber pip which I thought was for the pump NRV, is it the case that this goes in the assembly and replaces one of the brass pips ? Later I tried to light it and after the preheat I turned the on off valve and nothing happened, I rotated the on of and it jumped into life, and then died, tried rotating the valve again and it fired up nice and bright for few seconds but then stopped dead, after a few more rotations the jet squirted some paraffin into the "J" tube so I shut down. I suspect the foot valve on the Vaporizer and need to investigate
Hi Ray - there should only be one seal in the foot valve of the vapouriser assy. from the top - brass cup with seal and brass recess in it for the rod to push against. Below this is the spring. All this is inside the screw off housing. There is normally a fine gauze in the bottom of the housing. The other rubber in there will create havoc ! - pictures here: Restoration of a PETROMAX 829 Lantern
Excellent the picture shows what I was looking for. Later I'll strip it back and photograph mine I'll check the lamp for any id
Looking at the pictures in the link it seems like mine Part 193 is the one on top facing upwards, which the rod seats into its centre, and note the spring sits inside of the brass housing Part 17 is at the bottom facing down towards the screwdriver slot note the spring sits on the outside of this part the brass is turned down to accomodate it.
The very first variation of the 1350 (and the others) still had the level gauge and manometer fitting. I have seen other examples with the correct tank stamping for a 1350 but with the level gauge. These have all been with all the other features of the first variation, so I am guessing that it is either a transitional thing or there was a 'real' 1350 with these fittings. What I havn't seen is any catalogue evidence. To be sure in this case, we need a photo of the tank stamping.
Even though I view these lamps as basically Petromax-styled, there are unique little features that make these Swedish lanterns(especially the earlier ones) look very appealing(at least to me). Besides the usually high quality of metal work, these little features(extra level gauge, contour and shapes of the filler cap, style of locking slots on the pump cap, the way the pricker wheel was being attached to the stem, etc.) really make them a league above many other similar-styled clones. In my opinion, I think these might even be costlier to produce than the Petromax. Its almost like they were somehow being made differently from the rest despite having the same basic style. I'm sure you'd soon sort out the complications in the footvalve, @rayw .
Thanks for all the interest its a great way to learn about the lamp, and to solve the issues. First of all I took some pictures to show the lamp more clearly You can see the marking on thre collar But little info on the tank or base, looked all round and underneath Other side pre heat tube is broken may need to improvise an update on the situation. I slipped a plastic tube over the top of the jet and the vaporiser tube, pumped up the lamp and opened the valve, at first it seemed reluctant but then paraffin streamed out into a container, I let iit do that for a while then opened and closed the on off valve a few times, the stream stopped and started to order. Checked the gap between the jet niple and the "J" tube, its 14.2 mm may open that to 15mm, filled the pre heat and lit it (no glass but top was on) reluctantly at first but with some encouragement from my blow lamp it lit, I still had to turn the on off valve several times, it ran for a while but it has a bit of a flicker and one time it seemed to be starting to burn paraffin a few times with a yellow flame, it also had some flame outside the mantle. I'm convinced the foot valve on the vaporiser is playing up need to work on that.
@Fireexit1 It actually looks like a 350, see link: https://classicpressurelamps.com/attachments/opti-2-2-jpg.76324/ It had the same tag as on Tom's lantern. Isn't it a scratch mark looking like a "1" as in "1350"? No quick starter torch on it either.
That is something i had not considered, and could be possible, i took a look but couldn't see any markings on the base, and only the Optimus marking on the tank.
Yes, definitely a 350. It is also the very first variation as I mentioned above. The stamping on the tank is as used on the 350/550/1350/1550 series and the tag on the collar is the first type. I have never been impressed with the position of the preheat dish on these. It is too low to give good heating to the vapouriser. On the ones I use it usually takes 2 fills of the preheater and is still touch and go. Once they are going there is rarely a problem. Have you cleaned the loop on the vapouriser? If that is blocked then kerosene/paraffin can push past the restriction between the loop and unvapourised fuel gets to the jet.
I have read many times that the pre-heat arrangement on these is not so good. I have two 350/350cp, a 550/500cp and a 1350/350cp and all light first time using the pre-heat dish. Admittedly they are all in quite good mechanical condition. It is also hard to believe that as several military contracts for these existed that they would compare unfavourably to the competition. Even if they are not as "good" as a petromax or similar, they should have been good enough for use when the lamp was new.
Thats very interesting, can anyone put an approximate date on it? I was going to make this a regular user, but im not so sure now, my knowledge of lamps is pretty limited but i am beginning to regard the faithful old Tilleys as reliable workhorses, Willis and Bates products as better engineered Tilleys, but maybe not as bright, and some of the others as a bit tempremental thoroughbreds, perhaps its too early yet. Nonetheless i will plod on with this one, i intend to take the vaporizer back off and try to give it a sort out, looking at the foot valve it seems to just control the paraffin flow, allowing it to pass when the rod pushes the pip off its seat need to consider a new one, need to try and get something throughthe loop to be sure its clear.
Most of the ones that I have seen from military or civil defence use have been the 1350 or 15550. At least in Denmark, the assumption was that they were started using the quick starter. My experience with the preheat dish is that it depends a lot on the ambient temperature. I tried lighting one last weekend in 7 degrees and still got yellow flames even with two preheats. It did settle down eventually though. I started a Radius 119 at the same time and it started first time after one preheat.
@rayw This lamp will be from 1957 or just after. For a lamps with no quick starter, the foot valve is actually redundant. You can do a soft start with the jet clear (valve open) and turn off the lamp by releasing pressure.
- you know - I use the valve for lighting but release the pressure for switching off. I tend not to use the rapid starters so as to avoid glass damage. It never occurred to me that I could do a soft start. A good point well made!
