1925 -to- 1931 shorty Primus 70 details

Discussion in 'Stove Forum' started by OMC, Jan 15, 2020.

  1. OMC

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    Info recently emerged regarding Primus 70 & 71. This thread focuses on tank details / bare stoves but concludes with some tin info etc.

    The 1925-31 P70 developed from the same tank:
    >1/3 pint ribbed shorty tank, >small filler cap, >lettering front, back & top, >no date 'til '37
    TRADE MARK, PRI-*-MUS, PRIMUS No 70, MADE IN SWEDEN
    498n499L1.jpg

    BENZINE, BENZOLINE, NAPHTA, PETROL. .. PRIMUS SWEDEN in oval on flat top filler cap
    503.JPG

    Re 1/3 pint, per 1925 – 1937 catalogs capacity of tank is 1/3 Imp. Pint / 0.18 ltr.
    Re ribbed tank: above red arrow points to → ribbed shoulder of the tank, ergo ribbed tank.
    Re small filler cap it threads onto 13mm OD filler neck (only 1925 has vertical filler neck).
    Re safety pressure release 1925-30 P70 has only the concave bottom (that's it). If tank over pressurizes in danger of rupture, by-design the bottom pops out. This might avoid catastrophy, this would destroy the tank.
    a long post, please hold comments until -end-
     
  2. OMC

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    1925 No.70
    The No.70 was “Nyhet!” in 1925 per catalog .
    25P70SMa1.jpg
    credit SMolson
    Note, only on 1st ver. tank: A. vertical / upright filler neck. -and-
    B. text surrounding spirit cup: “ PATENT SV.No48624. ENG.No171536. ” (patent for A)
    25P70SMpat.jpg
    Oh and btw Smolson's is an excellent example. There are other details that relate only to c1925 version btw.
     
  3. OMC

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    c1926 -to- 1929,30 No.70 :
    26_29P70ML.JPG
    that is hex fitting at base of vaporizer btw
     
  4. OMC

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    Note, next is a c1931 stove… which I follow with a c1930 then go back to c1931. Yes.
    The changes with c1930 / 31 Primus 70 can be confusing. Hopefully each example is accurate (with what we know so far). Corrections welcome.

    c1931 No.70 tank
    Still has same tank, spirit cup R1067 on top and handle on side.
    The new safety pressure release pin indicative of 1931.
    combi8079v2.jpg
    (originally no valve btw: hex at base of no.70 vaporizer, 70 tank w/spirit cup)
     
  5. OMC

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    c1930,31 No. 70 with valve
    Tank changes: no handle and the spirit cup is integrated into tank (same text).
    The no safety release pin indicative of c1930/31.
    IMG_0518cut.JPG

    Other c1930,31 changes:
    spirit cup R1067 to NA
    burner head R1063 changed to 4063
    burner R1068 changed to 4060 burner with valve (aka vaporizer)
     
  6. OMC

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    c1931 No.70
    Safety release pin added otherwise it's the same as the previous example...
    71_01_SM_AnB.JPG
    credit SMolson
    … AND this ˄˄˄˄70 is the same stove as the following ˅˅˅˅ 71 example.
     
  7. OMC

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    c1931 No 71 ← yes, No.71. It is included here as FYI: it's the same as the previous example, the only change was the nr. on the tank to “71”.

    1931 is 1st version of Primus 71. Anomoly for this one, his (odd) square packing nut... is original.
    71_02_BG_dbl.JPG
    credit Bob Gibbon

    NOTE: re TANK, this same ribbed “tank” (w/integrated spirit cup) in use for the 71 shorty from 1931 to c1936.
     
  8. OMC

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    This focus is re tanks / (bare) stoves. The tins are related, the following is a TINDEX:

    GOLD TINS in use 1925 – 35 :
    > c1925 Primus 70 tins do not have the 6 large upper holes in tin.
    25P70gldTin.jpg
    credit SMolson


    > c1926-30 Primus 70 tins are the same as previous tin but 6 large holes are added (2 in front, 2 on each side).
    c26P702glTin.JPG
    credit Labagorri

    > 1931 – 1935 Primus 71 tins are the same as previous tin but BLANK, *the space on the tin where “Primus No. 70” was is left blank.
    31plusP712GldTin.jpg
    credit knight84
     
  9. OMC

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    BTW by 1936 came a “new” Primus 71 tin (10 hole) on left.
    36slvrShrt2.JPG
    credit optipri

    The “new” tin on the left is familiar to many stovies... or is it? You see in 1936,37 there was only one version.. the shorty version (ht: 133mm), it is fairly rare (to date).
    -----------------------------
    The, most familiar, taller (standard) version (ht: 143mm) came out in '38.
    BTW it is EASY to mistake one for the other, you really need to measure to confirm.
     
    Last edited: Jan 16, 2020
  10. OMC

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    Way above you may have noticed in link Bob Gibbon has a 71E.
    71_02_BG71E.jpg
    The “E” represents a 71 stove w/”Primus” cook set, they're nice kit when you can get one. Yeah about that (check me) my impression, they were 1st offered in '31 as an option *for the 71

    In '31 came 71D is a 71 that nests in a 2 pc. cooker
    ….............. 71E is a 71D cooker that nests in pot & pan (1 pot, 1 pan, cooker & stove)
    by 35 came 71K is a 71E cook set that nests in larger pot & pan (2 pots, 2 pans, cooker & stove).
    NOTE: this is 71D, E & K as seen in 1931-37catalogs.

    Mind you c31-37 : 71D cooker (stowed) ht: 95mm. 71E pot (cooker stowed) ht: 95mm.

    So height of stowed cooker 95mm, hold that thought.
     
    Last edited: Jan 16, 2020
  11. OMC

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    ˄˄˄˄above notes shorty '37 71E, 95mm pot is the same height as stowed cooker.

    Behold.... a '47 71K
    1220398776-Primus71k.jpg
    credit Pjotr

    His image shows us that^^^^ inner pot is taller than the (stowed) cooker.

    It shows us...
    Specifically a '47 71K is bigger than a '37 71K,
    and
    Generally the early Primus cook sets, 31-37 are smaller, made for the shorty 71s.
    then
    At some time after '38 there were also larger Primus 71 cook set models, to accommodate standard size 71s.
    -end-
     
  12. Tony Press

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    Very interesting, Mr C. I'll have to dig out my oldest 70s and 71s.

    Tony
     
  13. Barrett New Zealand

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    Yes very interesting @OMC, just last night I pointed out my 70 to a dinner guest and said I believed it was 1930.
    But you have clarified that its vertical filler makes it a 1925.
    I don't have the tin or reserve cap and chain, but the hole for chain is in the bottom of handle not the top, and it doesn't appear to have been touched/re-attached to my eyes at least.
    Informative post, thank you.

    Cheers
    Barrett
     
  14. Tony Press

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    @Barrett

    I have two Primus 70s with the little handle. One has the hole on the handle at the top, the other at the bottom.


    Cheers

    Tony
     
  15. Barrett New Zealand

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    @OMC, just an observation that my vertical filler cap only has "Primus" in the oval, no Sweden, it appears that SMolson pic shows the same Primus only cap?

    @Tony Press , I guess pre-drilled handles and no specific orientation observed at assembly time?

    Cheers
    Barrett
     
  16. Simes

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    @Barrett, or it was a 'Friday afternoon' job. :)
     
  17. OMC

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    Thanks all.
    "I think" every step of assembly was deliberate including hole location but it does have me confused.
    It is a detail of the bare tank (which I tend to focus on). Sadly, I find top vs bottom, at best is difficult to follow. It may be the sequence was top, then bottom then back to top (and maybe not). I did give up on it as a detail to rely on.

    The text on the filler cap (in my image(s))... that may become a source of confusion, sorry.
    The only reason i mentioned it above was to insert into the typed-in (searchable) text, the text on the tank in the image (non-searchable).
    I've not yet focused on any differences with the filler cap text. There are differences. If we can sort the best examples (most complete, most likely original) "some" of those differences may go away?

    While I'm here, FYI: I initiated a related discussion / Q&A re early P70 tin here.
     
    Last edited: Jan 16, 2020
  18. Tony Press

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    @Simes & @OMC

    I just did a count of Primus 70s in the Reference Gallery that had the slant filler cap and the handle:

    Eight had the chain hole at the bottom; seven at the top. That looks statistically random to me.

    Tony
     
  19. Simes

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    I'm on the way....
    Random will prove interesting I'm sure for some.

    The guys on the production line must have thought this'll mess with the heads of collectors in the future.
     
  20. MrAlexxx

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    A brilliant bit of research work! Well done. :thumbup::thumbup:

    Alex