I have got several no5 stoves of varius brands, and have afew primus no5 sor stoves, and a couple of no5 stoves. Does anyone know what the Sor means? do they perform any different? Thanks for any information that may be helpful
Howdy, Nzoomed, You might want to spend several evenings, scrolling through all the Primus catalogs that are available on this site for your research. Tons of outstanding, and wonderful, information to be had, and I never tire of checking them out. I do believe the answer to your question can be found within those Primus pages. Take care, and God Bless! Every Good Wish, Doc Mark
Hi Nzoomed I believe that the 5 Sor was a version of the 5, but made more to a budget, but I have no idea what it stands for. As Doc says trawling the other sections on the site will bring up a lot of information on these excellent stoves.
Hi, both Primus and Optimus made budget versions on their No.5 stoves, designated 5S. In an Optimus catalogue I have seen it stated that the brasswork on the 5 is 25% thicker than on the 5S. The 5 had a tank capacity of 2 pints nominal whereas the 5S is listed at 1.75 pints. They apparently saved one ounce of brass in manufacturing the 5S relative to the No.5.... An early example of "Value Engineering" ! It sticks in my mind that the "S" stands for Senior....but don't ask me why they called the inferior model that. Best Regards, Kerophile.
The answer to the designation "S:or" lies in the Primus filler cap patent of 1919. From 1920 this patent (a recessed filler cap - see the "patents" section on this site) was applied to the original silent and roarer domestic stoves. To distinguish between these new creations (which were now designated No. 1 & No. 5) and the original models (i.e. pre-filler cap patent), the older models were retained with the designation "Senior", perhaps logically complementing the designation "Junior", which had already been introduced for 2 pint stoves with smaller burners than the standard ones. Perhaps in order to justify a higher price for the new models 1 & 5, the Senior models (stamped S:or) 1 & 5 were made of slightly lighter gauge brass (although early examples are still much heavier than later AB BAHCO models 1 & 5), while the tank capacity was usually given as 2 1/8 pints, while the new 1 & 5 models were listed at 2 1/4 pints. In fact, judging by the ratio of surviving examples, the seniors (which were for all practical purposes identical in function to the newly introduced 1 & 5 models, and which used the same quality components) remained more popular than their more expensive replacements. Post-1920 models 1 & 5 survive in far smaller numbers than the seniors. The sunken filler cap made little practical difference to the operation of filling the stove and it didn't significantly add to the tank's fillable capacity. The last seniors were manufactured in 1955 after which the old lettering system (A-Z; then AA-AV) was replaced with a 6 digit code (ending with the two final digits of the year of manufacture from 56-64). The company stamp was changed from A(ktie)B(olaget) B. A. Hjorth & Co. to the contraction AB BAHCO. The Primus 1 & 5 models were made by BAHCO until the 1963 buy-out by A. B. Optimus, which then manufactured under the trade name PRIMUS TRADING AB, alongside identical stoves made under the Optimus and Svea (which Optimus had acquired from AB Max Sievert) names. AB Radius (founded by former Primus workers in 1913 after a strike at Primus) adopted the same "senior" designation by the 1930s, and appears to have fairly soon got round the Primus patent (since Radius No. 1 & No. 5 stoves also featured a sunken filler cap after 1930) while AB Optimus followed suit (designating its cheaper models as 1S and 5S), although it did not gain use of the Primus sunken filler patent until 1963, when all domestic nos. 1 & 5 stoves, whether bearing the name Optimus, Primus or Svea, were in fact identical in manufacture, and all featured the sunken filler cap (which Svea had also used from the 1940s on).
Hi to you Ed, and also to Ross, Paul and old friends from this site. It's some time since I have been in contact - so it will be nice to get back into the scene. Ross has done a fantastic job on the site. I have a few stove articles etc. to post, plus some new pics of interesting stoves I've picked up over the last couple of years.... Regards, Peter Watchorn PS: I just finished an 18 year book project that's kept me a bit occupied - comes out in November!
Hello to you, Peter! Terrific to see you dropping back by. 8) Would this be the brass keroburner book, by any chance.....?
PS (9 April, 2021, or 14 years later!): The Radius adoption of the Senior/S:or designation (at least for the silent/No. 5 stove) was, in fact, rather different from the Primus use/distinction, as the original Radius No. 5 used the silent burner with the one-piece perforated hood (no inner hood), often known as the "UFO" burner. The 5 S:or used the familiar Primus model silent burner (you can see this in the Radius catalogues from the late '20s/early '30s). Only on the (much) later Radius Ltd No. 5 stoves do we see the "sunken" filler hole and the familiar silent burner, and, on the No. 1, the sunken filler hole, plus standard roarer burner. The Primus S:or started as an "addendum" to the Junior /J:or models (which preceded them - you'll find Junior models in 1905, but not Seniors - those appear in 1907), as the early catalogues show: the announcement is from 1907), https://classiccampstoves.com/attachments/1219182617-008-jpg.110636/ featuring smaller size burners (both silent and roarer). After 1920 (or so), when the new patent for the sunken filler hole was introduced, the Senior models were the same as the Juniors, but with the large burners used on the Nos. 1 & 5. Lighter gauge brass; a bit cheaper; same size tanks.
