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Post by silverfox on Apr 18, 2012 18:46:32 GMT
This is the backhead of a B! boiler i bought sometime ago, The problem i have is this As it stands the top and bottom feeds for the sight glass are at an angle Do I 1) leave it alone, (i don't like the idea of that looks too traction engine!!) 2) make an extension piece so it lines up vertical ( bit messy but gets what i want) 3) as 2 but make a backhead cover to hide the pipework 4) get the bush shifted ( What problems would be lurking in doing this, I wont do it, get it done by a pro) All suggrstions welcome Thanks Ron (the other one) Attachments:
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Post by durhambuilder on Apr 18, 2012 19:03:35 GMT
I'd be tempted to leave well alone, my original AJAX drwgs had a slanting sight glass on the cab layout but a modified boss on the outside of the shell on the boiler drwg. This pic from Station Rd Steam shows the slanting version www.stationroadsteam.com/stock%20pages/2771whereas this Achillies (same boiler) shows the altered 'external' boss for a vertical glass www.stationroadsteam.com/stock%20pages/5220You wouldn't necessarily know what grade silver solder was used in the original construction, probably lower melting point than the cadmium free stuff the pro builders are obliged to use nowadays so the getting the whole lot hot enough to solder on another boss may be fraught with trouble. Cheers |
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Post by Deleted on Apr 18, 2012 20:36:37 GMT
Your boiler inspector wouldn't thank you for options 2/3, you have to able to rod through the water way to the boiler, to prove it's clear.
Adding a bush should be possible, but only if you can find some Easy-flo, and someone with the expertise to do it!
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Apr 18, 2012 21:34:43 GMT
G'day other Ron
Based on bad experiences I'd say the gauge glass is in the wrong position.
I doubt, but would like to be corrected, that the bottom nut will be above the firebox crown with sufficient water cover (10% of stean space in the AMSB Code.)
The effective glass length will be quite short. I've seem a very experienced driver friend come unstuck (thankfully the boiler didn't) because the glass was prototypical and not long enough to always see the meniscus. In the dark and in dappled sunlight full and empty glasses can look the same.
A bush in the wrapper to line the bottom fitting up with the bottom fitting would help.
Fitting such a bush you could use Comsol. This practice was proposed to me by none other than the secretary of the AMSB committee. Advantage you do not have to heat the boiler close to the melting point of the existing solder.
Regards
Ian
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denis M
Part of the e-furniture
Posts: 300
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Post by denis M on Apr 18, 2012 22:51:11 GMT
Leave well alone and use what you have. My Bagnall has water gauge glasses at an angle and never had a problem.
Denis
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Post by arch1947 on Apr 18, 2012 23:11:39 GMT
G'Day Ron, I agree with Ian about the size of the glass and that when you hit the bottom nut the water level if still above the top of the firbox crown. At and angle shouldn't be a problem but the AMBSC specifies a maximum of 45 degrees, I think ans superseven is correct about being able to check the water passages. I am not familiar with Comsol but if the AMBSC allows it then it would be OK. Would TIG welding a new bush/bushes in place be an option? I don't know the answer. What do others think.
Cheers,
Arch
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springbok
Statesman
Building a Thompson Class B1 in 5"g Plus restoring a 3" Fowler steam road Engine "The Wanderer".
Posts: 570
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Post by springbok on Apr 19, 2012 4:17:16 GMT
Hi
Firstly is this for a class B1 Springbok boiler (maybe a typo but says B!) I have a complete set of the drawings for this boiler and 3/4 way through construction of the loco. I will do some comparisons tomorrow and post you again
Bob
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Post by Shawki Shlemon on Apr 19, 2012 8:17:07 GMT
Looking at photo could be misleading because we don't know the distance between the bushes , generally for a round top boiler the top bush is on the top to give enough distance but there is no rule on that .
the other thing is once you fit the water gauge bottom fitting , the bottom of the glas should be as mentioned above the crown by 10% of the distance between the crown and the top of the wrapper . If you reposition the bottom bush the water gauge will be shorter. To fit another bush you be required to do another hydrostatic test , In my opinion if after fitting the bottom water gauge fitting the bottom of the glass is OK ( if not you can screen a little of the glass to get that ) , the length of the glass is .75" or more , I would leave it alone .
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Post by Boadicea on Apr 19, 2012 8:28:47 GMT
Yes, I think some may be looking at the wrong two bushes.
I assume you would propose to move the middle bush to make the sight glass vertical with the existing top bush. This looks to be OK from the water level point of view. I think it would be difficult to place it in a better vertical position. However, the new bottom sight glass bush would be getting close to the firehole opening.
This is an area well avoided for modification. It may well disturb the soldering of the firehole ring and that would be very difficult to put right. Many leaks around the firehole have proved impossible to fix and, at the very least, are for the "big boys."
My advice - come to terms with it if you can and live with it. There is only one real reason for moving it and that is to become prototypical - and just moving the bush will not achieve it, but I know how these things can get to people, you just do not like sloping gauges - fair enough.
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Apr 19, 2012 9:35:50 GMT
G'day other Ron. Based on bad experiences I'd say the gauge glass is in the wrong position. I doubt, but would like to be corrected, that the bottom nut will be above the firebox crown with sufficient water cover (10% of stean space in the AMSB Code.) The effective glass length will be quite short. I've seem a very experienced driver friend come unstuck (thankfully the boiler didn't) because the glass was prototypical and not long enough to always see the meniscus. In the dark and in dappled sunlight full and empty glasses can look the same. A bush in the wrapper to line the bottom fitting up with the bottom fitting would help. Regards Ian Morning Other Ron. A picture below of my 5" Springbok backhead with the floor out. As you can see, it is very similar except for the sight glass position. Are we all talking about the same two bushes for the sight glass here? My answer to the other question - leave well alone.  P.S. Eventually got the picture sorted but had to add a new post! |
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Post by steamjohn248 on Apr 19, 2012 21:07:01 GMT
The comment that in certain lights a full and empty glass can look the same is not true if you use red or blue line glass.
John
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Post by Shawki Shlemon on Apr 20, 2012 6:49:09 GMT
Tony , may I ask if the four in line stays above the fire door , are they longitudinal stays ? It seems the bottom of the glass tube is not higher than the crown , I may be wrong but just it looks like that to me . I am not criticising just wondering as we are discussing this issue on the other engine .
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Apr 20, 2012 7:45:22 GMT
Tony , may I ask if the four in line stays above the fire door , are they longitudinal stays ? It seems the bottom of the glass tube is not higher than the crown , I may be wrong but just it looks like that to me . I am not criticising just wondering as we are discussing this issue on the other engine . Yes, they are longitudinal stays. Shawki, you are correct, the bottom of the glass is about at the crown, a tad lower. It depends on what fitting is used I suppose - and a slightly higher "bottom of the glass" would mean it is OK if I can see water. It is probably better to have it higher, but at the moment at least, I am content as long as I know where it is. The comment that in certain lights a full and empty glass can look the same is not true if you use red or blue line glass. John John, very true and it works very well. The slanting stripes behind is also a good indicator. If desperate, opening and closing the blowdown will allow you to see the water descend and recover in the glass, if overfull. If not - desperation!  |
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Post by peterseager on Apr 20, 2012 16:27:59 GMT
Last year I did a footplate experience on an Ivatt Class 2. I was surprised how often the fireman blew done the gauge glass. Not without good reason, the name of the game seemed to be keeping the safety valves from blowing rather than keeping the water below the top of the gauge glass. After driving models, driving and firing the real thing was certainly an different experience.
Peter
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Post by Shawki Shlemon on Apr 21, 2012 6:38:26 GMT
Thanks Tony for the answer , I am sure you know this , when you have time ,you can make a new bottom nut with a sleeve to hide say 3/16" from the bottom of the glass and then anyone can drive the engine without worry .Just an idea . I have done that myself on one engine .
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