The idea behind this post is that it can be used to verify that a patent 00 stove has the correct fittings on it for its particular version. The basic concept seems sound but we will have to see how workable it is. My patent 00s are now spread around the world so in writing this I am relying on my memory or remaining photographs. Memory is fallible so I apologise for any errors that my age causes. I would suggest that the administrators revise this post as corrections are are made and that people who supply information to update it are given credit for their contributions rather than me receiving sole credit for it if it proves workable BURNER All burners are roarer 1 pint burners. All should be marked OPTIMUS. Any marked OPTIMUS SWEDEN or OPTIMUS PRIMUS or simply SWEDEN are later replacements as are unbranded burners. Any silent burners or 2 pint burners are replacements and you have not found a new version FLAME RING I think the flame ring should be marked OPTIMUS SWEDEN but that needs verification. Any flame ring marked SWEDEN SWEDEN is a later replacement LEGS AND HOUSINGS LONG COLLARED LEGS Bun footed stoves have these legs. They fit into an open bottomless housing on the side of the tank. They are correct for the bun footed stoves both with the internal NRV and the external NRV. Any fitted to later stoves are replacements LONG KINKED LEGS Rigid footed stoves have these legs which fit into housings at the top of the foot fitting. They also appear on bun footed stoves however they are interchangeable so they could be original equipment on that version or a later replacement fitted to an early stove. Any fitted to a tank with folding feet are replacements and suggest that the stove has been fitted with a 2 pint burner. SHORT KINKED LEGS. These are fitted to the tanks with folding feet PRIMUS LEGS Primus legs are interchangeable with the Optimus legs and there appears to be a high incidence of Primus legs fitted to patent 00s. The bends at the top of the legs are different. Both makers kept the same shape during their stove manufacture. However Primus stoves made after 1962 were made by Optimus so have Optimus bends on them. You can check both firm’s bends by looking at the drawings on the parts lists, checking fixed leg stoves or comparing the legs from stoves of both makes in your collection. Until I was attacked (again) for stating that an Optimus stove had Primus legs I assumed that this would be common knowledge so had never mentioned it. SPIRIT CUPS All spirit cups have dimples in it RISING TUBES AND RESERVE LIDS All bun footed stoves and all rigid footed stoves have tall and wide rising tubes. These stoves have a large reserve lid with a flange around the top. All folding footed stoves have the later stumpy and narrow rising tubes which were used until the model went out of production. These have the small reserve lid with diamond knurling on them Any reserve lids with vertical knurling are later replacements RESERVE LID PARKING The bun footed and rigid footed stoves have parking bosses on the tank top. The reserve lids park on the pump knob on folding footed footed stoves TANK LID Bun footed and fixed footed stoves have a tank lid with a rubber washer sealed air screw on top. Folding footed stoves have a tank lid with a metal to metal sealed air screw MARKINGS ON TANK All tanks are marked MADE IN SWEDEN. I had a stove that showed no factory location and I assumed that it must be a very early stove. That was on a bun footed stove with internal NRV. However Ross’s bun footed stove with external NRV is marked STOCKHOLM which I had assumed was a later marking. I do not know whether my stove was correct in being unmarked or whether it is a manufacturing defect. If the absence of factory location is intentional it means that the stove started with an internal NRV then it had an external NRV and then it reverted to an internal NRV all on the bun footed stoves. So the stoves with the external NRV should be marked STOCKHOLM as should later bun footed stoves. Stoves with rigid feet on the tank edges should be marked STOCKHOLM. Early folding footed stoves are marked STOCKHOLM and later ones are marked UPPLANDS VASBY although this marking is rare. TANK AND PUMP There are two tanks caused by the different pump arrangements. The markings on the tank suggest that the tanks started with an internal NRV and then the tank had to be adapted to take the external NRV and then reverted to the plain tank on the bun footed stoves. I am not comfortable with this order because I had always assumed that the rarer external NRV stoves were first. There is currently no information to verify either order so make your own mind up. The tanks with folding feet are the same as were made until the model was dropped. PUMP KNOB The bun footed and fixed footed stoves have a bell shaped pump knob. The folding footed stoves have a bell shaped pump knob threaded externally to provide parking for the reserve lid. The bell shape on these knobs is not as pronounced as the earlier knob or the later slim line version. It is a different shape so any slim line knobs are later replacements FEET Bun footed stoves came first. Fixed footed stoves were second. Folding footed stoves were last PATENT The patent had to apply to something on the tank because there are too many external changes for the patent to have applied to those parts. If you compare the tank of this stove with other comparable stoves you will see no external difference so the patent had to apply to something inside the tank. The central rising tube attachment is fixed to the tank with a nut inside as well as being soldered and I suspect that it is patented part. The date of the patent is not known nor is the duration of the patent. Either of those facts would help with dating the different versions. The patent seems to have only applied to 1 pint stoves as I have never seen it marked on a 2 pint stove however it is marked on an Optimus 200 tank which was the same as the 00 but with different fittings on it In 1892 the roarer burner was patented by Svensen who then went on to make Primus stoves. Patents show the date of the first application, the date that the full application was made and the date that the patent was granted They do not show the expiry date which is extremely frustrating In 1899 Optimus started up and produced stoves with burners identical to the patented Primus burner. The patent must have expired so at that time the patent period must have expired and at that time the patent period could not have exceeded 7 years. Patent periods are currently 20 years however that period is not automatic. Annual fees have to be paid to keep the patent valid. In America the period can be extended if there is a long period between the initial application and the granting of the patent. In normal circumstances the period starts from the initial application. Can anyone decipher the patent periods because this would at least identify how long the patents lasted even if we did not know when they started? It would date other Optimus stoves with known patent dates DATING Three of the design features on this stove are copied from a Primus stove that had those features were created because of an Englishman who had odd tastes but very fixed ideas in what he wanted. The features are:- the collared legs, the bun feet and the tank lid with the rubber sealed air screw. The first positive date that the Primus stove (No 230) appears is 1905 and other information suggests that this date is correct or if not very close to the model start Primus used those features on other models. There was another new feature not used on the 00 but which was used on all of the Primus 96 models up until 1962. That is using a pump cap instead of a pump knob. Early Primus 96s also used all of the Primus design features. By 1914 Primus had removed the collared legs and that tank lid from the 96. By 1921 the feet had been moved from the bottom of the 96 to the side. So by that time Primus had dropped all of the odd design features used on the 00s Stove makers copied each others stoves shamelessly and I believe that Optimus copied the design features off Primus. Those features were created solely to satisfy an Englishman’s requirements so there was no reason for any other maker to create them The documentary evidence show that Optimus could not have copied the features prior to 1905 which is the first date that the Primus 230 is mentioned. They are unlikely to have copied them after 1921 because the stoves had been improved and those features had been dropped. The patent 00 was created somewhere between these dates but most probably very close to 1905. Now we have a possible start date and if we had the patent period we have the finish date of the patent 00. Please check the technical details in case my memory is faulty. The format of the post is not perfect but I have presented the information in a manner that will help the recovery of individual features without having to wade through a lot of information which is not relevant to your research. You picked a right weekend to go away Ross. Friday night and Saturday night must have been a bit memorable. Regards Bryan
I little 'wild' but more on that later! I'll compare notes with you later. Sad you've been attacked, & twice to boot over your opinions! That is outrageous & behaviour I only expect of the more academically inclined lamp collectors.
So much to go through! Like Dave I've printed this out. That way I can leave the screen & digest it a bit at a time. Initial browsing of Optimus material looks like the very sloped legs (for the OO) were an early & later feature with a more primus type leg inbetween. Dimples in spirit-cups - not visible in early parts lists or my earliest example. Folding foot - reserve cap on pump knob? On later generation folders. Immediately post bun feet reserve cap was on tank, as per the following link & the 1929 brochure . Both show a hex cap on the tank. https://classiccampstoves.com/threads/951 As you may have noticed I've moved this to the 00 section. One thing I think we need to do is illustrate the features mentioned. I'm happy to provide illustrations after running them past you to clarify correctness with your text. One of the stoves I need help with is the fixed/rigid foot 00 as I have no photo's or drawings of that.
Hi Ross I will catch up with you later as I am preparing stoves for listing tonight. However very briefly. The legs on stoves that I have had conform to the Optimus shape throughout the periods 1930s 1950s, 1960s, 1970s and 1980s. Several of the stoves were unused so the legs should be original. I have no original legged stoves that can be identified from the 1900s, 1910s or 1920s so cannot say that the shape definitely continued through those periods however I would think that it is likely It may be more reliable to check 1 & 5 stoves as they have fixed legs which are unlikely to have been changed I had forgotten about the hexagon reserve lid. The external NRV stove had a hole in the back of the stove for the NRV fitting so I called that a different tank however it is only different in that it has the hole. The rest of the tank is constant throughout the life of the patent. Please provide any photos that you think are necessary. I no longer have any patent 00s so would be relying on old photos which may not illustrate the necessary parts. I will have a proper look at your questions later as I have probably answered questions that you have not asked and missed ones that you have asked Something is making me feel uncomfortable about what I have written and I cannot identify what is bothering me. Could I deliver your burner and look at your patent 00s and literature to see what is bugging me? It is that annoying feeling that you have missed something. It may be important or it may be something that does not matter. You mentioned that you had a 1911? Primus 1 pinter. Could you have a look at the tank and see if has patent written on it and if so what is the patent number? Regards Bryan
Dumb question regarding the burner and Svensen's patent. Bryan states that if Optimus was manufacturing a "copy" of the Primus burner in 1899 then the patent must have expired. Here's my dumb question - could it not be the case that Optimus was legally manufacturing their burner whilst the patent was still in force via a negotiated per unit licence fee paid to Primus (or indeed direct to Svensen as the patent holder "off" Primus company books). It would seem a reasonable approach to make money from a competitor, and to a minor extent influence their cost base, if they were going to manufacture stoves anyway?
Hi Graham I like your questions better than Ross's! It is not a dumb question. There are indications that could be the case but there are also indications that it is unlikely. Primus means the first. Optimus means the best. It seems unlikely that a firm would give a license to someone who claimed that their stoves were superior to the one holding the Patent. However there are circumstances which might prompt Primus to give licenses. They often had fires which disrupted production and on some occasions destroyed the factory. That would seriously affect their profit. If they gave a license to another maker during one of these disruptions they would get some income instead of none. However if they gave a license they would have a whip hand and would be able to withdraw the license if the firm that had a license started to copy their own products which were not included in the license. I believe there were a lot of court cases for infringement of the patent. Primus might have decided it was less bother to issue licenses than constantly go to court. Holding's Baby Primus (230) is marked Patent but I have not been given the patent number and unfortunately I upset the archivist so it would be undiplomatic to ask for it Ross mentioned a 1911? 1 pint Primus and I have asked him if it has a patent number on it . If that number is 3944 the other firms must have had licenses Back to being annoyed by difficult stoves. Regards Bryan
Was Svensen still involved with Primus? Did he ever assign the patent to Primus or did he keep it personally. If the patent was never assigned to become an asset of Primus it would be Svensen assigning any licences and any fees would be going straight into his pocket. If he was heavily financially involved with Primus, any licence fees from Optimus would form a safety net should Primus go under for any reason, taking his investment with it. Just thinking out loud really, and putting myself in Svensen's shoes. I personally wouldn't let marketing perceptions vis a vis the latin meanings of Primus and Optimus get in the way of practicality
Hi Bryan, here is a link to an Early (1920s) Optimus No.1 Traveller; https://classiccampstoves.com/threads/9012 and here is another one: https://classiccampstoves.com/threads/4881 Look at the tight bends at the top of the legs. I know these stoves have replaceable legs, but surely you would concede the possibilty that Optimus used more than one design of upper bend on its legs. Otherwise we are back to you telling us that all these stoves have retro-fitted Primus legs. Best Regards, Kerophile.
Firstly - lets give the man credit & get his name right - it was Svenson. Even in sweden it is often misspelt, usually as Svensson. He was with the business until 1904. More info on his major involvement can be found in the articles section. https://classiccampstoves.com/threads/17 There were court cases - I need to get some info on this translated as I do have some info on one case between Primus & Optimus. Bryan - you are welcome anytime & who am I to complain if I get the burner delivered at the same time - sounds like a good deal to me! I will lay out as much as I can in advance. I don't have any later 00's unless there's some down the shed. Maybe something I need to address, but my interest is in the earlier stuff. From memory the leg profile varied between the Optimus types - ie fixed leg & removable & then again within the removables. No worries about feeling uncomfortable about what you wrote. I'm really pleased to see this sort of debate on the forum - it is what the site is about after all. Some things will change as new info comes to light but it's easy to edit the original guide with any verified updates & delete any replies (such as this). For now it's best to consider this a debate. Later we can make it into the best definitive guide that we can. One thing that excites me as a collector is new variants of the early models. Just like the original 96 model you brought to my attention I was totally unaware of a fixed foot 00. If anyone has got photo's of one they can post in the this gallery I'd appreciate it.
George - you posted while I was typing. I have examples of both of those. On one of mine a leg has been lost & been replaced with piece of threaded rod bent to the right shape. I know of at least 3 profiles used by Optimus. I need to get my finger out & get some early stuff in the library but for now check out the 1929 brochure.
It's good to see this gallery filling up & attention being made to the detail & the differences. Kerophile has just posted another 00 here: https://classiccampstoves.com/threads/10259 This is the Upplands Vasby marked tank. This has the threaded pump knob. I have scant detail for these for the bulk of the 1920's but the 1929 brochure lists a pump knob that is common to other models that weren't threaded for the reserve cap. That puts threaded pump knobs at post 1929. The 1934 catalogue shows the tank with the hex reserve cap on a tank boss but in the parts diagram it shows the threaded pump-knob & round, knurled reserve cap. This is not uncommon - for the catalogue product drawings to be out of date but the parts list to be accurate - far more important for the dealers. That puts the date for moving the reserve cap from the tank to between 1930 & 1934. Hope that is of some assistance.
Hi Ross, would you re-consider the date estimate on your "Patent" Op.00 in light of your revised dating for the shift of the reserve cap to the pump-knob? https://classiccampstoves.com/threads/952 Do you think your stove is earlier or later than my Upplands Vasby "Patent" stove? The boxes do look similar, although yours is in much better condition. Best Regards, Kerophile.
Hi Ross I wish you had not said that. Over the years I have had several patent 00s and all are now sold. That was a version that I think but was not absolutely certain existed and I hoped that you would know about it. If no one confirms that it exists it will be better knocking it out. Obviously the hex reserve lid needs adding on. Both my stove and George's have the slightly odd shaped pump knob with the external thread for reserve lid parking. Doug Weise now owns the one that I had I had a bun footed stove with internal NRV. It had no factory address in fact there was no marking around the sides. I assumed that the stove had to have been made before the protocol was established for marking the factory location on the tank side. After that Stockholm got marked on the side and then Upplands Vasby got marked on the side. The tanks with the external NRV looked to me to be very early partly because of the valve design and partly because of their rarity. However your 00 with the external NRV clearly has Stockholm marked on the side that that completely gooses my logic and I now have no idea what order that the stoves came. The simple answer may be that someone forgot to mark the side of my stove RISING TUBE AND LEGS I am uncomfortable with using terms like long, high, wide, stumpy and narrow in these items because those are opinions which vary from person to person. It would be better if measurements were used instead. I have measured the last rising tube which I think coincides with the one on the last Patent 00. Its sizes are 17 mm spanner x 23mm high Hi Graham I do not read Swedish but the way that the patent appears to read suggests that Svensen applied for the patent in his name and Linqvist is name as the inventor. By 1904 Svenson had left the company and I think that it had become Primus instead of Svensons. If the patent was still in force Svenson could have still owned and could have been licensing other companies to makle the burners. However usually if an item is made under license that is stated on the item. I have not seen any burners that were definitely early so it is possible that they were marked in that way Hi George You seem to be misunderstanding my position. You have produced a large number of stoves with "Primus" bends. All of those were collapsible stoves. There is a simple explanation for that high incidence. If Optimus stopped making that length leg stove owners would have no choice but to buy the Primus ones if they were still in production. Ross has stated that the parts lists show the Optimus bends at the beginning and end of the run. My stoves show that the bend was used consistently from the 1930s to the finish of the stove manufacture. They were also used near the beginning of the patent 00. There is a simple explanation for that apparent change. If the parts list were drawn by an external agent who also produced Primus parts lists they could have drawn the wrong bend by mistake. The parts lists are solely for part number identification so would not be a problem for Optimus because they are not working drawings for making the parts. We seem to have a different objective mine is to find the truth. My current position is that I think the bend was used during the whole period but that there is circumstantial evidence contradicting that. Primus legs have serrations on the top. I have never come across Optimus stoves with this feature. Do your legs have serrations along the top or are they plain? If plain it would support the assumption that they were made by Optimus. There is evidence that would be irrevocable. If the "Primus" type bends appeared on a non collapsible stove. Unfortunately if the stoves only have Optimus bends on them it is still not proof that those bends were not used for the duration of the stove making. It merely suggests that most stoves had the "Optimus" bend. Could you please check your domestic stoves? I do not look for evidence to support my argument. I look for all available evidence and then try to work out what it means. Personal feelings do not come into these decisions Regards Bryan.
Yes I would. I nearly added a comment that I would have to revise an estimate of one of my own 00's based on that newly realized info. I'll do that shortly. My gut tells me the one's marked Upplands Vasby are the later of the 'Patent' 00's - I can't see them bringing that in & then going back to plain 'Sweden'. I'll think some more on that one. That comment re the boss moving post 1939 is because the '39 catalogue shows it on the tank - I've since learnt to look at the parts diagrams! The 39 uses the same image as the 34 catalogue - also out of date!
Of course not! Otherwise we'd never get anywhere. I've looked around other collectors sites & through my old photo's & I'm with George on this at the moment. I also don't see a co-relation between the shape of fixed & collapsible models. I may be missing the point here so if it's not resolved by the time you come around you can show me what you mean. I've got all my old Primus 1 pinters out as well!
Damn - I wanted it to be out there! Statements like that always make me uncomfortable! Damn - looks like some of my early Primus stoves may have Optimus legs! (only joking but they are not all serrated)
Hi Ross They do not make me comfortable. It is simply to show that there are explanations that can fit not that it is true. There are always more than one explanation and the correct one may not be obvious. When you look at the adverts and other documents they are not exactly accurate. You gave me a 111 advert which shows two stoves. The one in the foreground is correct. The one in the background has an oval tank with no tube between it and the burner. That sort of information does not inspire confidence in any of the documents. From my point of view it is possible that Optimus used more than one bend BUT my hard evidence contradicts your documentary evidence however my hard evidence does not cover the full manufacturing period so I do not find either evidence conclusive. Whilst the bends on domestic stoves might not be the same at least it would rule that source of information out if they were examined and found to be different. I am now short of all stoves so cannot check the serrations but they seem to come up fairly often because I sometimes find that I have three legs of matching bends but some of them have those ruddy serrations so the legs cannot be used. At one time I worked out a brilliant way to identify early Optimus stoves. The very early ones had the o of No double underlined and newer ones were single underlined. It worked perfectly however it turned out that I had accidentally got all older ones with double underlining whilst there were also some with single underling. The reverse was the case with later ones. At that point I said "Oh bother" Regards Bryan
Aye - I have that sign on my wall. Pictures of Bo Rymans can be found here. I think you can allow a bit more artistic licence with this type of medium! The catalogue material tends to be accurate but the pictures can be out of date rather than complete rubbish like the background stove in that ad. I am finding the parts listings & diagrams to be the thing to study. I thought my documentary evidence was backing up MY hard evidence & that in other collections I've seen? I checked out the 00 pics on the disk you gave me of your sales & I'm beginning to think the difference in these legs you are mentioning is subtle as I can only see the pronounced slope on very early & later stoves. I'm hoping it will all become clear when you come round.
