Once I destroyed NRV with flimsy tool so I needed to dig out NRV by screw extractor. First I drilled 4 mm hole with left spiral drill bit thought the hole in NRV.(left hand drill bit will put some force to opening direction of NRV and might help to loose NRV) With #3 (M8-M11 = 5/16"-7/16") screw extractor I screwed NRV out. Drill bit nor extractor were not long enough to reach NRV so I used pin vice as an extension for them. (you can also use thread tap extenders for extractor, but didn't had them on that time. Now I have 8-[ )
Thanks guys! You're very kind. Yes Nick, I did. Sorry for not being clear on that. It was some years ago, but I think it was a rainy day when I got bored, and remembered that I long have had the idea to make a (slightly) improved version of the Primus 1596. So I went down in the basement, made a very quick prototype to test if it worked - which it did - so I realised the idea in a more permanent way. Sometimes bad weather is a good thing. If you noticed that the hex nut at the top is split in two parts, it's just because I wanted the tool to be dismantable in case some of the three loose parts in the middle needed replacement later on. Otherwise it would of course have been better to just weld one hex piece (with the t-handle, if desired) on the rest after all had been assembled. Here's all parts disassembled, except for the t-handle. As you can see, the stem with its two threads (M10) and the tools head are turned and cut in one solid piece. The discoloration of the head is after hardening and tempering. (A polish took out most of the brownish look after tempering.) Actually the two-piece nut works as it should. The idea is that I just need to tighten them together real hard, and after that they won't unthread when using the tool in it's normal counterclockwise direction for loosening an NRV. And it works. When it's hard stuck valves we talk about, and I use a spanner, it's just important to use the inner part of the two-pieced nut. Then it will act in a sort of "self-locking" way. When all is tightened up really hard, it looks like below. You can see that the two pieces aren't really lined up as in the first pictures I showed. Function before form, out of necessity...: Another thing I was experimenting with initially, was to make something that allowed the lift that the freed, rotating NRV, unevitably will produce. I used e.g. two cupped washers, but also tried a short, really stiff spring, as seen here (and above since i placed it there for these photos): It does work, but in reality it's really not needed. More of an addition to complicate stuff more. A stubborn NRV gets free with a distinct snap, and the twist it makes when breaking loose is much less than a quarter of a full turn, meaning perhaps a tenth or two of a mm. in axial movement. Even if the tool is tightened up snug, which it shouldn't be, that short movement is taken up by the flex of all materials involved.
Thanks Nick and Kerry. I found the "prototype" I mentioned above - the one I made just to test the theory of this tool first. I never throw anything away. It's a quick fix that anyone can do in a very short time if they want to try this type of tool. It's just a threaded rod, M8 stainless steel in this case, with a tools head and a bunch of nuts at the strategical places, and an old pump cap for screwing it all down on the pump tube. The only thing that has to be made is the head with it's slot and threaded hole plus that the old discarded pump cap need to have its hole enlarged: It works in the same way as when using the more elaborated one with a spanner: As said: it's quickly done for anyone who want to test it, and to be honest... it actually does the job almost as good as the more finished one despite its crappy appearence.
Hey, Christer, Excellent tutorial, and fine design in your locking NRV tool!! I don't have any machining skills, whatsoever, so I'll probably not mess with trying to cobble one up for myself. But, the idea is very sound, and very practical, and you did a great thing in coming up with it, and making it happen!! Well done, and many thanks for sharing it here!! 8) Thanks, again, and God Bless! Every Good Wish, Mark
Thanks for your kind words Doc! You actually don't need much skill to do stuff like this. It's quite easy, but time consuming for us happy amateurs. No, it's rather a case of having the machinery, and I guess that´s where the trouble is for most people. I'm sure you could do something like the makeshift version I showed last. To make e.g. the slot quickly without having any machinery, it's just to mark 5 mm, take a hacksaw and saw two grooves. Then saw a third one inbetween the first, and pry away the two thin ridges that are left. Takes just a couple of minutes. Might need some trimming with a file.
Hi, Christer, You are most welcome, my friend. Excellent work! I once made a sort of NRV with a very thick lag screw/bolt. It worked OK on a few things but failed on my old Campingo #1. That's when I got both of Stu's excellent NRV tools. One of them did the trick on that Campingo, as I'm sure yours would do, too!! I may try my hand at making something like your original prototype, but we'll see how it goes. Great idea, though, that's for sure!! Talk to you later, and God Bless! Every Good Wish, Mark P.S. Here's a photo of my then just completed home brewed NRV "tool": Chunky little thing, and not near as nice as the ones that you make, nor as nice as Stu's. It was fun making it, though. I used a dremel tool to get started, then files. I still have it, but rarely use it anymore. Oh, the standard NRV tool, laying across my vise, was just to compare the slot measurements.
Hi Christer I do like your NRV tool. It looks like the 'bees knees' !! Your prototype looks to be much more in my league to make. Even so, I think it needs a good number of tools to make it. It would be useful if you could list all that is needed.
Great job you made of that Christer and it improves on the Primus original, which I agree looks flimsy, as does Primus NRV tool No. 1616 which I use, which nevertheless hasn't failed me yet. By having not a slot but a socket to fit the NRV head precisely the No. 1616 tool is effective but not as sophisticated a solution as yours is. John
G,,day Christer . I love the simplicity of the prototype . bloody clever thinking !!! but it has given me an idea . I am NOT criticising Stu,s tools , I have them both and have found them extremely good . but I have just thought , cut the T handle off and thread the shaft , several ways to deal with the top . just an idea if I ever need to . thanks mate , for sharing the idea cheers, kerry
Yeah, Celsius. That's not an unusual sight. It's a pain in the arse, but it's also good practice to be forced to de-solder the pump. Thanks Kerry! Yes, I think it's better to have a versatile top of the tool. The hex is very good for this in my experience. I agree john. The 1616 works fair enough, but that t-handle is a joke. It's good for seating new NRV's, but not good for releasing tough ones. I have bent those small sticks on mine. That's probably one reason I made other versions instead. Cheers Trevor. To make the test version, all tools needed is a hacksaw (and possibly a flat file if the slot isn't cut precise from the beginning) a drill bit of 6.8 mm and an M8 tap. A power drill is of course also helpful. A vice is probably a good thing, but there are other ways to fasten the things when working on them. Making the slot with the hacksaw is of course just one example for those with limited tool setup, but it works with a surprising precision. A dremel works well too, just as e.g. an angle grinder, which is the quickest way, but also the esaiest to over size the slot. Doc, that tool you made looks perfect in my opinion. If the slot is snug, and the bolt you used hard, it should cope with most NRV's you encounter.
Good Morning, Christer, Thank you for your kind words, my friend, but your tool makes mine want to go home to it's Momma and never show it's face again!! If I had known how to braze, I'd have affixed a sturdy T-handle to the top of the big bolt head, as that would have made the whole thing work better. But, once I got Stu's tools, I never had the desire to better the chunky one that I made. Now, your design is so wonderful, that I just might have to give the prototype style a try! Me thinks even a "shade tree fettler" like meself, might be able to accomplish it, given your excellent instructions! 8) Thanks, again, for sharing your design ideas, and God Bless! Every Good Wish, Mark
hi im Edward im new ive always loved stoves and ive just started collecting. please could you tell me what ATF is, thankyou very much
@Christer Carlsson Good evening. Christer, your tools are beautiful. Regarding the "prototype". Do you have any recommendation on what to build the tools head from? I.e what regular hardware store object can be slotted and drilled with a M8 threading tool and still be hard enough not to be deformed when engaging the NRV? Thanks /Daniel
