Hi in a recent post John (Presscall) raised the topic of removal of an NRV with a slotted base from an early design Optimus No.1 dating from 1914/18? https://classiccampstoves.com/threads/15377 In the past I have always kept clear of the debate as to the purpose of the slot on the base of an NRV on a classic stove. In this case, as John points out, there can be no debate. A screwdriver is the only tool which can be used to remove this particular NRV from the stove, so presumably that was the intention of the designer. The "modern" NRV is a straight forward, and fairly minor, development of this design, so again it seems logical that a screwdriver, rather than a gripping tool on the cylinder, was the intended tool for dismantling the NRV, once it has been removed from the tank. Now, I hear you ask "What have you been using for your NRVs for all these years, and hundreds of NRVs?" Well, in my stove tool-roll I have an old paint scraper. The sort with a piece of triangular steel mounted on a straight 6mm diam shaft. The 3 blades of this scraper are each about 30mm long, of different profile, and fairly sharp. I find you can select one to get a perfect, tight, fit on the slot of an NRV cylinder, once it has been removed from its stove. The head of the NRV is held in an engineer's vice, or more commonly my home-made NRV key. Using the above method I have only "lost" 2 or 3 NRV cylinders to torsion failure, in literally hundreds of individual dismantling operations, some with truly ancient a totally jammed NRVs. I have tried the alternative cylinder gripping method but can see no advantages and many additional hazards, such as crushing the cylinder or badly marking the surface. If you think of the failure mode of cylinders in torsion, it makes little difference whether you apply the torque with a tightly fitting blade in the slot, or using a gripping tool on the cylinder. The actual failure mode is the same. Just My two-penny worth. Best Regards, Kerophile.
Hi George, For those (like me) whose English knowledge is so limited, your explanations are highly difficult to follow. Instead you could put a photo here. Please....
This is the way I would prefer to do it as eventually you will mess one up. Use a pair of pliers or grips that has a suitable form. Not like this But like this Grip, gently mind, just below the threaded part. Hold with a removal key or another pair of grips at the top, my preferred way is to hold in a vice thus. Hope this helps, a picture paints a thousand words
Hi Sefa, here are photos as requested: This curved blade of this shave-hook is also ideal for tightening the carrier for leather washers on a pump piston: Hope this helps. Best Regards, George.
