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.
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