pault
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Post by pault on Jan 13, 2014 22:03:58 GMT
You can do it with 2 pieces and a glass but I think you would want to use a thicker glass than a microscope slide. The glass in the gauge glasses in the picture are 17.5 mm thick although they are much bigger and working at higher pressure.
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Post by arch1947 on Jan 13, 2014 23:19:15 GMT
Hi Dianne, If you go with the slot then the fitting that holds the glass would reinforce the backhead and minimise any distortion. Pauls idea of holes top and bottom sounds good and provided the gauge "fitting" was sufficiently robust/stiff the number of fixing screws would be small.
Cheers,
Arch
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jma1009
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Post by jma1009 on Jan 13, 2014 23:31:56 GMT
the other alternative to the standard LBSC type water gauge is the water gauge described by K.N. Harris in his book 'Model Boilers and Boilermaking' (MAP) and also described by him in ME around 1954. it is very compact. my 3.5"g GWR KING has a water gauge made to this design. cheers, julian Attachment Deleted |
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jma1009
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Post by jma1009 on Jan 13, 2014 23:33:12 GMT
the other alternative to the standard LBSC type water gauge is the water gauge described by K.N. Harris in his book 'Model Boilers and Boilermaking' (MAP) and also described by him in ME around 1954. it is very compact. my 3.5"g GWR KING has a water gauge made to this design. cheers, julian  |
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jma1009
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Post by jma1009 on Jan 14, 2014 0:17:04 GMT
 this is probably the most 'compact' ive made an LBSC type water gauge. 5"g, 7/32" dia glass with 5/16" AF gland nuts. a GWR type blowdown valve in appearance, but is actually a globe valve that is captive in the sense that it cant be turned anymore than 200 degrees coz the handle fouls the backhead. glass showing between the gland nuts is 5/8". it will be noted that the spigots that the gland nuts screw onto must be threaded and silver soldered to the top and bottom fittings first as otherwise the flanges for the fittings gets in the way of the die. a bit of profiling of the top and bottom fittings i think improves the appearance - but means they have to made out of quite large chunks and milled down. the boiler bushes are threaded 5/16" x 32 tpi. the globe valve requires some careful machining and silver soldering as the passageways need making before silver soldering in the spigots. cheers, julian |
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Post by wdiannes on Jan 14, 2014 0:59:52 GMT
Nice job Julian!!! Very nice.
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Post by Deleted on Jan 14, 2014 22:09:48 GMT
Small, but perfectly formed !!
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Post by wdiannes on Jan 14, 2014 22:58:09 GMT
Awe gee Hagley, I thought you were talking about ME!  Very nice Julian! |
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Post by Deleted on Jan 14, 2014 23:34:27 GMT
Awe gee Hagley, I thought you were talking about ME! Very nice Julian! haha.. I was tempted to say.. 'same as me'.. but I'm not that good a liar...  Pete |
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Post by Nigel Bennett on Jan 15, 2014 13:11:16 GMT
What about the Neville Evans design of water gauge? I think (like we all do) he pinched the idea from somebody else whose name now escapes me.
He used it on his Stowe "Schools" design amongst others - the gauge glass is held in compression and is sealed by O rings top and bottom. There's a special screw in the top fitting that applies the loading. It dispense with the conventional nuts and would allow a longer viewable length of glass.
Not too difficult to make - but finishing the ends of the glass smooth and square and to a fairly accurate length is not easy. (I used a diamond file with the glass lightly held in the drilling machine in a collet chuck.)
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Post by modeng2000 on Jan 15, 2014 19:37:10 GMT
Nigel, do you know of any information about the Neville Evans water gauge please?
John
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jma1009
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Post by jma1009 on Jan 17, 2014 1:32:21 GMT
hi nigel and john,
the neville evans version you mention is the same as the K.N.Harris design i referred to and which i have made. it isnt an easy gauge to make, and one needs to avoid the compressed internal rubber or 'O' rings obstructing the passageways. it is only of advantage when you want a very 'compact' scale gauge. mine had a solid frame between top and bottom fittings which i think from memory is slightly at variance with the neville evans version. however the internals are the same.
cheers,
julian
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Post by modeng2000 on Jan 17, 2014 7:55:19 GMT
Thanks Julian, I've always thought I should have a copy of K N Harris' boiler book.
Expect there will be one at AP this weekend.
John
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