Hi George here's a couple of photos of your new NRV tools i've just finished. The small one is the standard design ,but the big one is a little different, it has a sliding piece the same size as the tool itself. The idea is that if you have a badly stuck NRV the sliding piece of the shaft can be placed at the strongest part of the pump to hold it square while you apply turning pressure. Hope you like them, i'll get them in the post tomorow when you send me your address. best regards Stu. Ps just tried the big one on my no25 1935 vintage & no probs ,popped off like a good'un, Stu.
Your tools are well made Stu. However, how does one still keep the tool from rising off of the flats? I don't have anything big enough or wide enough to accomodate squeezing the tank and tool between to prevent this. Some may say though, that if it needs that much pressure/torque, better to remove the pump tube. Experts are torn both ways.
Hi Ron. Well I've been between a rock and a hard spot before, just need to do that with stoves with NRV issues. Slowly gaining valuable info on fettling stoves. I haven't destroyed a stove yet in the learning process, so maybe past life experiences have paved the way for me on what not to do and what will happen if I use wrong procedures. There was that engine I had to take back out because the clutch made funny noises, all because I installed a throw out bearing 180 degrees the wrong way. Doh!
ChefBC, we have had our share of mistakes in stove fettling and difficult as it is to accept that we have broken a part which may be difficult to replace is the end result Ron
I have pondered about the same problem with the NRV tool rising off the flats, burring both the NRV as well as the tool sometimes. I have what I feel is a solution to the design of the tool itself and I wonder what demand there is for a good tool that will do the job without damaging NRV's and necessitating only a little downward pressure when using it. Is there anyone interested in manufacturing such a tool(x 1000's) for supply? PM me if you are interested. John
Pump tubes of the same diameter come in varying lengths but are roughly the same size give or take an inch. How about if the a section of the tool was threaded in the zone that corresponds with the top end of the tube & a captive, pump cap was fitted - with the centre re-bored & threaded to match. This could be used to lock the tool in place. You'd find the odd stove with a different thread on the pump tube that wouldn't take the cap but it could be left undone in those rare cases. I think I've seen something along those lines in the tool section of a stove/lamp/blowlamp catalogue - will have a browse.
Hi all Ross's idea sounds like a good one. If the slide idea had a locking grub screw that could alter the length for any pump tube, & hold it secure up against a pump cap that was placed permanently in between the handle, it might just work. The only problems that i can see is the weakest link in the chain could be the, tearing off of the tube bottom , distortion of the tube ends & pump cap threads stripped & ruined due to mechanical pressure as the NRV is loosened (they are only fine threads). If the tool rises off the NRV i still agree it may be better to desolder. With a difficult NRV i put some folded old towels on the floor, kneel down, place the tank/fount between my knees,& use enough downward pressure to keep the tool in place, never had one mess me about this way!! Best regards Stu.
Hi, I agree with Stu that before using any NRV removal tool, ask yourself which is the weakest link in the chain. I find that by asking myself "what part is likely to give first?" helps me in deciding how much downward force to exert on the tool, and how much torque to apply before calling it a day and reaching for the gas-torch. I like the idea of the sliding spacer that Stu has designed for the larger tool. I intend to hold in in place with a nylon cable-tie fastened on the central shaft. I should then be able to slide the top spacer to the optimum position for each stove type. I'm certainly looking forward to "road-testing" the new tools. Best Regards, Kerophile.
The idea I have works pretty much like what an Optimus No.111 type wrench or a universal ended roarer burner wrench does, on burner nipples. When in position, the edge of the wrench working area is in contact with only about half the surface on the nipple flats. It has more grip and is less likely to ride up the flats. My idea is roughly like the design below: This idea can be applied to stuck or slightly burred non return valve(s) in pump tubes. John
Primus made a similar tool to the one you describes. It had a stop on the tool shaft and what looked like a regular pump lid above the stop to lock the tool in place once attached to the NRV. The stop was fixed, so it was obviously made for one tube length alone, but it wouldn't be any diffiult thing to manufacture this tool, and then with an adjustable stop instead. I haven't seen it in any catalogue, but it was discussed at BBL many years ago. That's where I learned about its existance myself. I will try to find that link. Edit: I found it! Look here. Scroll directly down to post#7, and you'll see the Primus tool. Apart from the locking device, it also has a guide at the lower end which will centre the tool in the tube.
This is what Primus came up with: No. 1596 Official tools are usually designed for situations like those on the drawingboard, and little beyond. All the expressed concerns are valid imo, but 'usually' the forces needed can be contained with this neat setup as long as the valve is not bodged. It appears to fit on all swedish 2-pint (discus) stoves - also the german makes - that have the bigger diameter pump housing. On the only SVEA 105 still here (106's have the small diam. pump!) it just assembles on the first 2-3 threads, but that can be circumstantial. In general, the reverse setup of having the tool in a vise and the tank pressed down on it, is the best way to unlock a seized NRV. Otherwise a 'pumpectomy' is in order.
Yes, that's exactly the same kind of tool I was referring to in the post above. And here is a catalogue sheet with it: It's from one of the Primus catalogues (1930's) in the reference library.
Hi Also what you need to consider is, if everything is locked up tight how does the NRV unscrew. Automotive tools for rewinding caliper pistons are threaded so the tool unwinds at the same (or similar) rate to keep in constant contact with the piston. To apply this to NRVs' you could thread the tool and a pump tube cap with a similar pitch to an NRV and as the NRV unscrewed they would stay in mesh. Have I explained myself properly? On lunch only have a few minutes. Or just get the torch out
Yep, you have explained yourself properly, and I agree. A "following" tool would have been much better. But since these tools were factory made and people uses them, they probably work. But I assume that you only can release the NRV the very first critical bit to get it "un-stuck". After that you obviously must unscrew the cap to be able to continue with the removal of the NRV.
Just put a red hot rod down on the nrv to loosen the lead washer has worked for me. except for the time the end cap fell in the tank and the other one with the factory screwed in till it near sheared no washer technique of sealing. Anyone else tried a impact wrench type effect with a nrv tool??? Sort of a Y shaft on the end. You get a rod or bar and whack it down the inside of the legs you want it to turn. The impact imparts a downward but also torsional twist. Don't answer I know I know I'll get me coat.
The main problem with the NRV removal tool is it sliding off the NRV. I have been thinking of making one that just slides over the NRV, and then widens up a bit so it only grips at the base of the NRV (hope this makes sence to you ). Can be done easily with a small file (the ones with a cross-section that is not flat, but slopes. We call these a 'knife-file', dunno what their brit name is. Sorry for my not-so-good technical English ) Regards, Wim
