Svea 123 or 123R Spindle Key Uses

The Swedish-made Svea 123R is a great stove. The “R” means it has a built-in cleaning needle. The spindle key that comes with the vintage stoves has several cut-outs in the key. The purpose of the cut-outs is to lighten the spindle key, to allow the key to dissipate heat and to serve as useful tools for the stove in the field. Here is a quick explanation of the functions of the tool cutouts in the spindle key.

Swedish-made Svea 123R with spindle key

Spindle key detail

Svea 123R – Loosen fuel cap

Svea 123R – Adjust spindle nut and tighten graphite packing

Svea 123R – loosen/tighten jet

The predecessor of the Svea 123R is the Svea 123 (it has no “R” in the stove name.) The spindle key that was bundled with Svea 123R stoves also had cutouts for this earlier version, the Svea 123. The keys were used interchangeably during the years that both types of stoves were co-produced.

Svea 123R stove on right. Svea 123 (no R) on the left.

The spindle nut is smaller on the Svea 123, and the opening in the photo below is used to tighten or loosen the spindle nut. Usually used to tighten the nut as the graphite packing in the spindle wears with use.

This part of the tool is for the spindle nut on the Svea 123 (no R)

This part of the tool is for the smaller jet on the Svea 123 (no R)

The cheaply made and low quality Optimus Svea 123R stoves now coming out of Taiwan still feature a spindle key that includes the opening for the Svea 123 spindle nut even though the Taiwanese never made that stove and that stove stopped being produced in Sweden pre-1970.

Some people, new to these sorts of stoves, or with little background on these stoves, will claim that the Taiwan stoves are of equal quality. But, sadly, those people have never had a genuine Swedish-made Svea in their hands. It is fairly well documented on social discussion forums about stoves that the Taiwanese Svea 123R stoves are of lesser fit and finish than the original Swedish made stoves. There have been quite a few reports about failures to positively shut-off straight out of the box. In my own work repairing stoves I have had a half dozen brand new Taiwanese Svea 123Rs sent to me in just the last year for failures to positively shut-off. The spindle seats are often poorly formed and the brand new stoves will leak right out of the box. If you are considering the purchase of a Svea 123R, PLEASE buy a used vintage one. There are lots of them around and they are much better made than the poor quality Taiwan stoves.

Primus Stove, Lantern and Appliance Dating Chart

Primus paraffin stoves, lanterns and blow lamps (blowtorches) are stamped with a letter code starting in 1911. The letter code can be found on the bottom of the tanks of these liquid fuel pressure appliances. The letters Q and AQ are not used in the coding system. Starting in 1955, the code method changed and a six-digit code was used. The last two digits of the six-digit code correspond to the year of production. The six-digit code can often be found on the leg of the stove or on the burner riser of the stove. Toward the end of the last years of Primus production, the code was no longer stamped on the stove but was found on the carton the stove shipped in.
There is often an additional number or letter stamped on the tank. It is unclear what this was for, but it is possible it was a production line identifier, or lot batch number.

Primus is the only liquid-fueled pressure appliance company of which I am aware that dated their offerings with a date code. Other manufacturers appliances must be dated by examining the features of the appliance and comparing them to catalog drawings, photos, illustrations and known dated appliances of the type.

You are welcome to freely copy and distribute this dating chart, link to the dating chart, or link to this webpage. Click on the chart or the photos below for larger and higher resolution images. While I made this chart from scratch, I am not the originator of the chart. For the record, I only published my homemade chart here after I saw that the original chart (found on a popular and well-known social discussion forum requiring a membership and/or subscription fee) has been published in full resolution far and wide all over Pinterest. So, the horse has already escaped the barn. I do not believe knowledge should be held ransom behind a subscription fee. Apparently a lot of Pinterest users agree, and you should agree, too. đź‘Ť

Here are some examples:

1920 Primus #100 Stove – marked “J”

1920 Primus #100 Stove – marked “J”

1936 Primus #100 Stove – marked “AA”

1936 Primus #100 Stove – marked “AA”

1946 Primus #71 Stove – marked “AK”

1946 Primus #71 Stove – marked “AK”

NRV Head Dimensions

Hi BD
I want to fix my old stove and I need to get the NRV out of the pump tube to replace the old rotten pip. I tried to buy one of those NRV wrenches from S. Korea and, then, from the UK, but those sellers don’t seem to be able to ship overseas due to COVID-19. Can you tell me the dimensions of the NRV head, please?
TIA, Old Stove Guy
Hi, Old Stove Guy
Sure. You bet. Here are some photos. All measurements in millimeters. This is a genuine Sweden-stamped and Swedish-made NRV. The dimensions are proper for the vast majority of NRVs in stoves out there. Be aware there are a few stove companies that vary from this style. Optimus, Primus, Radius, Svea/Sievert and Enders all use this style of NRV.
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Length
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Width
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Depth
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Head diameter (just for interest)
Iif you are a home hobby sort, it’s probably easiest to take a steel bolt just under the inside diameter of your pump tube, cut off the threads with a hacksaw, and then cut a slot just slightly undersized in the end of the cut-off bolt with the hacksaw. Clean the cut to exact dimensions with a file. The end will look like the end of this more polished out-of-production NRV wrench made by now-retired and out-of-sight tool maker Stu Burgess in England: (In other words, you can’t get these any more.)
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If you are more of a machinist, maybe have a vertical mill, you can use a 4mm end mill with two passes in your mill and make a closed end wrench like this:
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The closed-end wrench just above is an original Optimus wrench for marine stoves. The advantage of the closed end wrench is that it won’t do this in use:
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I tried to make this one up from a bolt recently to fit into a specialty off-brand stove whose NRV head is down inside a pocket in the end of the pump tube. That’s a rare stove and you don’t have that concern.
The failed example I show directly above is made from a too small diameter bolt. So, try to keep your bolt as large in diameter as you can to avoid the sides bending out like this. More material gives better support.
Lastly… here are some unsolicited pointers:
  1.  – the best way I’ve found to remove NRVs is to put the wrench upright in a vise, put the stove over the wrench, then use strong downward force on the tank to keep the wrench head on the NRV head so it doesn’t skip off the end of the wrench. I demonstrate the technique in this section of one of my YouTube videos: https://youtu.be/2LKsxIYCTko?t=226
  2.  – tighten the NRV just slightly/gently before trying to untighten. This may help to break the brass-to-brass bond if there is no NRV head washer present
  3.  – if you chose to use penetrants… it will do no good at all to put the penetrating oils down the pump tube. The NRV is air and liquid tight sealed inside that pump tube. Instead, use a small brush and reach inside the tank through the fuel filler to apply penetrant to the outsides of the pump tube where it will run down the tube and get into the exposed threads of the NRV that are hanging out at the end of the threaded pump tube end block. That is where you want penetrating oils to assist.
Hope that helps. Good luck!
BD

Stove Thread Specifications

For quite some time I’ve been machining adapters and reproduction parts for vintage stoves. I’ve been doing this on much of my client work as needed. I’ve always taken the if-it-could-be-done-before-it-can-be-done-again approach. As I’m getting a bit older, I thought now would be a good time to start recording some of the measured and *proven* threads or thread approximates I’ve come up with that will work well on vintage stoves.

But… first an important fact to understand. The various companies that made stoves (Optimus, Primus, Radius, even Coleman, etc) DID NOT necessarily conform to established “thread standards” for much of their work. This is especially true of the early standards established by Primus at the end of the 19th century (1890’s). Standardized threads would include the metric system, the British system or the American system. Some of these threads may appear on some stoves. But, for the most part, the threads used on vintage stoves are in-house creations of the production staff at the various firms and DID NOT conform to established standards.

Since Primus was the first to get stoves out there, and because they established a wide-spread international network of stove sellers and stove part houses (think todays franchises for fast food), other manufacturers were pretty much required to adapt their thread forms so that they could sell various parts that would mate with Primus stoves. Doing so meant that a Radius burner would fit perfectly on a Primus stove riser, for example.

So, yeah. I *know* that Sweden adopted the metric system in blah-blah year. Doesn’t matter. Stove threads pretty much ignore thread standards, and, that’s what makes stoving both fun and frustrating.

If you are a hobby machinist, you could make a bundle of money making up stove accessories and adapters for some of these old stoves. Sell them on eBay! I sincerely encourage you to do so. You’d be surprised what stove collectors will pay for a bit of brass properly threaded with compatible threads for their stove.

So, here’s the start of the list. I’ll add to it as I find time and energy. I have notebooks full of thread data. Check back whenever you like or if you need data for your stove restoration project.

NRV Threads
The head of most NRVs (non-return valve) found in kerosene-fueled stoves is threaded M8x0.75. The barrel of the NRV is threaded M6x0.75. These are non-standard metric sizes.

Stay tuned for more as I find time. BD