Optimus 48

Discussion in 'Optimus No:48' started by SNOWGOOSE, Oct 2, 2011.

  1. SNOWGOOSE

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    The Optimus 48 is a 1.75 pint “Household” stove with silent burner.

    Optimus stoves are difficult to date and unfortunately there are only four examples of the model 48 in the Stove Reference Gallery.

    The four examples of the 48 in the Stove Reference Gallery are all different in minor ways.

    Before I attempt to attempt to date this particular 48 I should write something about this stove.

    The stove tank was cleaned in soapy water to get an idea of its condition. It is dint free. The burner, inner and outer cap were cleaned in soapy water and then cleaned with Ciprox.

    I replaced the pump leather with one made by Sefa. I removed the NRV which had a solid pip. This was replaced with an Exeter Yak kit of pip, cup and spring made especially for the “NEW” type NRV. A Spiritburner HDPE washer was fitted to the collar of the NRV. The rising tube lead washer was replaced. The 18mm solid rubber air release/filler cap gasket was, when reversed, still viable. I fitted Kerophile heat resistant washers to the burner. On firing the stove up I quickly established that the jet did not need replacing.

    What I wanted was a working stove, which I now have. I have decided for the time being not to clean the tank with Ciprox.

    Now as to the age of this Optimus 48.

    There are several indicators that this stove was produced after the formation of the Primus Trading Co. in 1962.

    If one looks carefully at the outer burner caps in the four examples of the Optimus 48 in the Stove Reference Gallery one will note the following:

    One one of Kerophile’s see this:
    https://classiccampstoves.com/threads/4699
    the cap is marked Made in Sweden.

    In this post by Kerophile:

    https://classiccampstoves.com/threads/10014
    the cap is marked Optimus Sweden.

    Spiritburner’s post:

    https://classiccampstoves.com/threads/9152
    The cap is marked Made in Sweden

    In Motoshi Makino’s post see:

    https://classiccampstoves.com/threads/8978
    The cap is marked Optimus Sweden.

    The outer cap on my Optimus 48 is Optimus Primus showing that it must be post 1962 when Optimus bought the Primus brand name.

    The spirit cup on my 48 is marked Primus and this cup would probably have come with all the Primus parts when Optimus bought Primus.

    According to the article AB Optimus International, in the Stove Reference Library, see:
    https://classiccampstoves.com/threads/20

    In 1983 Optimus sold it's factory in Upplands Väsby & outsourced it's production.

    I believe that this Optimus 48 was made before 1983 as if the production was outsourced the new manufacturer, probably in the Far East, would not have had access to Primus parts (the Primus spirit cup).

    My 48 was probably produced without a reserve lid as there is no parking thread on the pump handle.

    In Kerophile’s 48, see:

    https://classiccampstoves.com/threads/4699

    One can see the reserve lid parked on the end of the pump handle. Also note that Kerophile’s 48 has the air release mounted on top of the filler cap.

    When one looks at Kerophile’s other 48, is not so clear from the three photos whether the reserve lid is on the pump handle:

    https://classiccampstoves.com/threads/10014



    In Spiritburner’s post of his 1974 Optimus 48 seen here:

    https://classiccampstoves.com/threads/9152

    do note the reserve lid parked on the end of the pump.

    And Motoshi’s wonderful 48 seen here:

    https://classiccampstoves.com/threads/8978

    also has the reserve lid parked on the end of the pump rod.

    Both Motoshi’s and Spiritburner’s 48’s have the airscrew mounted on the side of the filler cap.

    Another date indicator can be seen on the base of the tank. It is merely stamped Made in Sweden, rather than A.B. Optimus Uppl-Väsby.

    After looking at the four Optimus 48’s in the Stove Reference Gallery all I can be fairly sure on is that this stove was made after 1962 and most likely between 1972 and 1983.

    Some photos, first a flame shot:

    1317565774-R0020015A_opt.jpg

    The stove, it came without a trivet:

    1317565844-R0020069A_opt.jpg

    But when I need a trivet I can use one from my 45 or other Discus stoves:

    1317565942-R0020077A_opt.jpg

    The air release/tank filling cap:

    1317565992-R0020051A_opt.jpg

    The pump handle, note the pump rod is steel rather than brass:

    1317566175-R0020036A_opt.jpg

    The outer cap:

    1317566309-R0020084A_opt.jpg

    The spirit cup:

    1317566517-R0020091A_opt.jpg

    It is a 48:

    1317566596-R0020054A_opt.jpg

    Another date indicator can be seen on the base of the tank. It is merely stamped Made in Sweden, rather than A.B. Optimus Uppl-Väsby.

    1317566701-R0020063A_opt.jpg

    Finally, some more flame shots:

    1317566773-R0019966A_opt.jpg

    1317566823-R0019967b_opt.jpg

    1317566890-R0019999b_opt_opt.jpg

    1317566946-R0020018A_opt.jpg
     
    Last edited by a moderator: Jul 2, 2015
  2. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Rob, Lovely photos, as usual and interesting observations on your Optimus No.48, and the others posted in the Gallery.

    I will try to look at the details on my Op.48 stoves tomorrow. I actually had 4 but gave one to a friend, but I still have one to post images of in the Reference Gallery.

    I believe that the Op48 and Op.45 stoves were probably manufactured side-by-side, so my earlier observations on the positioning of the filler cap and air-screw on the Op.45, are likely to also apply to the Op.48 and so should help in approximate "dating" of these stoves.

    The sunken filler nozzle was introduced as a new feature on the Op.45 and Op48 stoves in the approx 1957/8 catalogue, so that also assists dating.

    I feel that your stove must have been fitted with a reserve cap when it left the factory. If you buy one from Doug Weise, or Base Camp I will donate a threaded pump-cap.

    Keep up the good work,
    Best Regards,
    George.
     
  3. SNOWGOOSE

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    Hi George,

    I did forget to add one photo - one with the reserve cap I bought from Basecamp:

    1317654072-R0020030A_opt.jpg

    It is very nice of you to offer to donate me a threaded pump cap!

    Cheers,

    Rob
     
    Last edited by a moderator: Jun 26, 2015
  4. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Robert. some thoughts about the date-period of your nice Op.48.

    1. Tank marked "Made In Sweden", and the silent cap stamped Optimus Primus certainly indicates post-1962 and the formation of the PTC.

    2. Sunken, or recessed, filler up-stand indicates post 1957/8 and the introduction of this feature to Optimus No.45 and 48 stoves.

    3. The air-screw mounted on the side of the filler up-stand is shown in the 1972 catalogue but not in the 1962 catalogue, where the air-screw is mounted on the filler up-stand.

    So, your stove would seem to be definitely post-1962 and perhaps into the late 1970s. It is certainly a bit later than my three "Optimus" Optimus 48s.
    What do you think?

    Best Regards,
    George.
     
  5. SNOWGOOSE

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    Hi George,

    Yes I agree. I wrote in my post "After looking at the four Optimus 48’s in the Stove Reference Gallery all I can be fairly sure on is that this stove was made after 1962 and most likely between 1972 and 1983."

    I am leaning towards late seventies or early eighties...one of the last!

    Cheers,

    Rob
     
    Last edited by a moderator: Jul 2, 2015
  6. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi Rob, I have found this exchange very useful, as it encouraged me to get my thoughts organised.

    I am now turning my attention to the Optimus 45 stoves I have, and those posted in the Reference Gallery to see if we can put approximate dates on them. I believe that the same "rules" apply as to the timing of the appearance of features, as on the Op.48 models.

    I hope you will have a go as well.

    Best Regards,
    George.