Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Aug 30, 2014 9:18:56 GMT
Having witnessed someone, on trying out his newly completed loco, leaning out on the move to view the music of the motion and falling off, I thought I had seen it all! As for Julian's idiots, I was that man in my early days. It was with a club loco and I was trying to get the injector to go, looking at the injector not the handle, and went too far. The valve handle went over my shoulder but was quickly found and refitted by someone with asbestos hands. It was pretty frightening for a newcomer - about on a par with a water gauge fracture. The difference with valves is this kind of accident is completely preventable and it makes sense to make them captive - I have for my own. Presumably those writing the regs have their reasons but their thinking is not clear. Off topic, but one for Hagley again. Since he has let slip about GPO - something I use regularly. Not quite complete and there is the odd interloper but overall pretty well intact. PO No. 1,2,5 and 6 - not pretty but the best screwdrivers in the world! (Other screwdrivers are available!)
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Post by Deleted on Aug 30, 2014 9:31:40 GMT
I've still got all my ex GPO tools as well. Must still have the wallet somewhere! The wire strippers, cutters and '81s' weren't as good quality in the later years but the screwdrivers were always good. You were allowed to keep your tools when you left, except for power tools.
John
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uuu
Elder Statesman
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Post by uuu on Aug 30, 2014 11:11:37 GMT
I have seen commercial fittings with captive spindles (I forget whose),but they were't very nice. I think they'd left the thread at the previous size and thinned down the rest. Spindly spindles. The handles may just have been nutted on, no squares.
Wilf
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 30, 2014 13:24:10 GMT
hi wilf, when i entered IMLEC in 1995 one entrant who will remain nameless (but built some superb locos which ive always admired) had to retire because his blower valve handle wasnt fitted on a square. the retaining nut worked loose and the handle spun loose on the spindle. lots of commercial fittings have handles not fitted on squares. another pet hate of mine is water gauges fitted with ordinary tapered plug cocks - they invariably jam up, plus unless the water gauge bodies are made very large the hole through the plugs and passages is less than the bore of the glass. anyway, back to the workshop and finishing the stainless spindles for the boiler blowdowns! cheers, julian
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Post by Deleted on Aug 30, 2014 17:59:49 GMT
The last of the many----I also have the Pipe Pliers and a "plethora" of assorted Whit. and Unified spanners of all sorts..............Yellow = FOOTPRINT GPO INST 4 1971, Smaller version is a permanent member of my motorcycle tool kit ( for carb tuning, etc.., Small Red = FOOTPRINT PO 1975, Large Red = marking faded too much......Alas, I couldn't rescue the old Megger Meter with the winding handle !!..........
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Aug 31, 2014 8:08:19 GMT
The last of the many----I also have the Pipe Pliers and a "plethora" of assorted Whit. and Unified spanners of all sorts..............Alas, I couldn't rescue the old Megger Meter with the winding handle !!..........] Like this you mean. Now collected because of the bakelite. Evershed and Vignoles - a name which sounds right - like Adcock and Shipley. Please bear with us folks - the plot should be found again soon!
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 31, 2014 10:46:21 GMT
not really 'scale' boiler fittings, but ive nearly finished the 2 boiler blowdown valves. just the bosses to be silver soldered on for the pipes when ive removed the boiler from the frames so that the pipes will point downwards when screwed into the bosses, and hex ends to be filed on the stainless spindles. anyway the bodies are machined out of hard drawn phos bronze and are 5/16" shorter than the martin evans design which seem to have clearance issues. the above valves are captive having a short retaining cap on the spindle/screwed into the end of the body. the hex ends on the spindles will be 3/16" AF hex, the spindles being turned down to 0.214". i will make up a suitable 'key' to operate them from a socket head cap screw. cheers, julian
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Post by Deleted on Aug 31, 2014 13:04:19 GMT
Hi Julian
The original blowdown valve on my Modelworks Britannia looked similar to your photo above, with a fitting on the outer end screwing into the same thread as the valve itself. However in the early days of running I unscrewed the valve as far as it would go without really watching what I was doing, and the spindle shot out and gave me a nasty scald on the wrist - luckily the boiler was nearly empty and the pressure probably only about 10psi. It appears that the outer nut was a tightish fit on the spindle and had unscrewed along with the spindle. Entirely my fault for not checking more carefully that the outer fitting was tightly locked down. I've since fitted a commercial blowdown valve which seems to be of a different design.
Kind regards, John
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 31, 2014 18:23:48 GMT
hi john, im sorry to hear of your accident with your Brit. needless to say the above 'caps' are a tight fit, whereas the spindles are an easy fit. ive used a similar although larger variation of the above for a few years without any mishaps. i gather that Modelworks werent that particular about fits or concentricity im afraid so am not surprised you encountered a problem im afraid. cheers, julian
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Aug 31, 2014 18:44:52 GMT
here's the backhead so far. apologies for the poor quality of the pics - my digi camera seems to have gone a bit hay wire recently. ive made a start on the 'globe' valves for the injector steam valves that go on top of the barrel on the A1X boiler. instead of making a form tool like john did with his lovely Brit, i used a radius tool then a clockmakers gravel to get the correct shape ie 3/8" dia. the recesses for the spigots to be silver soldered in position about to be milled with a 5/32" dia end mill for 1/4" x 40 tpi spigots for the union connections. the globe valves require some very careful internal work on the passages to ensure they supply enough steam for the injectors on such a small valve body. cheers, julian
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Post by Deleted on Aug 31, 2014 18:54:37 GMT
Hi Julian
Yes, Modelworks' accuracy did leave something to be desired (although they were much better than Winson by all accounts - they did use CNC machinery, but I guess that's only as good as the person doing the programming).
Any other Modelworks Brit owners reading this and using the original blowdown valve might like to open out the hole in the end cap and make sure that it's tightly screwed down. Having a captive fitting that doesn't actually work is arguably worse than no captive fitting at all - there's a temptation to open the valve until it reaches the stop!
Kind regards, John
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Post by suctionhose on Sept 1, 2014 7:13:31 GMT
With regard to captive spindles, the same occurred (winding them right out under steam) here (Aust) often enough to make captive spindles a requirement in the Boiler Code. Well. under the subject of scale fittings I have just finished 2 safety valves for my green narrow gauge Fowler. I like making safety valves and decided to try a different style. ps they're a bit big for JMA at about 1 1/2" high. 5/16" bore.
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Sept 1, 2014 13:33:43 GMT
The steam valves from Polly Model Engineering are captive, at least the ones they have sent me certainly are.
I think the H n S brigade would be better off looking at limiting car accelerator pedals than messing about with model steam engine valve details.
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Post by Deleted on Sept 1, 2014 15:31:08 GMT
The steam valves from Polly Model Engineering are captive, at least the ones they have sent me certainly are. I think the H n S brigade would be better off looking at limiting car accelerator pedals than messing about with model steam engine valve details. Hey...leave those accelerator pedals alone....I kind of like mine just as it is.... Pete
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uuu
Elder Statesman
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Post by uuu on Sept 1, 2014 19:50:50 GMT
Isn't it a throttle?
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Post by Deleted on Sept 1, 2014 21:55:09 GMT
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 1, 2014 22:18:12 GMT
to get back on topic, here's a bit more progress on the injector steam valves of 'globe' type with the connections for the boiler barrel bushes press fitted into position. as these fittings are above the water line plus require some very fiddly drilling of the internal passages they are made out of brass. inside of cereal packet drawing and notes in the background. the valves will get parted off the 'stick' once the passages are drilled and bits silver soldered in position. cheers, julian
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Post by Roger on Sept 2, 2014 6:54:21 GMT
Very neat indeed. What's the idea of the spot face on the middle of the globe section?
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 2, 2014 7:46:56 GMT
thanks roger, the other recesses (1/16" deep) are for the threaded spigots for the unions to screw onto for the steam feed down the pipes to the injectors. the bits are all press fitted together after drilling the angled passageways, then silver soldered in position. then the spigots are drilled through to connect with the passages. the valves on the fullsize STEPNEY are in the following pic posted previously on the loco build thread modeleng.proboards.com/attachment/download/3197cheers, julian
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Post by Roger on Sept 2, 2014 7:51:26 GMT
Ah, I see, that makes sense. I suppose you can't drill the internal angled holes unless you can gut up close to the globe. Does the Silver soldering only go over the outside of the pressed fits or do you make clearances to let the Silver Solder penetrate the joint?
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