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Post by alanetm on Sept 30, 2011 12:34:47 GMT
I am in the throes of building the boiler and have reached the stage of doing the back end. The tapered section, tubes and tube plate and throat plate have all gone together well. I thought a quick check between the frames was wise having put the fire box wrapper on and found the boiler would not go in. The reason was the blowdown connection. It is shown as a silver soldered right angled connection to the throat plate. This foules the bottom stay between the frames. It should be a bush so the blow down connection can screw into it in the gap between the upper and lower stays. I now have to do the modification..... boo
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Post by Andy Clark on Oct 2, 2011 23:05:05 GMT
Thanks for the heads up - I reckon the boiler is on my to do list for about 4-6 months time!
Andy
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taff
Hi-poster
President of City of Newport M.E.S. Chairman, Rivet Counters Fellowship.
Posts: 161
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Post by taff on Oct 2, 2011 23:08:24 GMT
Hello alanetm, Purely by coincidence I have just, about a fortnight ago, designed this boiler for a Churchward 31xx 2-6-2 tank loco which was the forerunner of the 5101 class. On most of the full size larger G.W. boilers the blow down valve was located at the bottom of the backhead usually just to the left of centre a position which was normally clear of obstructions. I appreciate that you now have the flange secured in your boiler but If you do have to redesign then the backhead may be an answer. I appreciate that the foundation ring slopes to the front but I have always put the blowdown flange on the backhead on my boilers.
Taff
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Post by Laurie_B on Oct 10, 2011 9:37:17 GMT
Hello Alan,Andy and Taff.
Sorry to read you're having problems Alan. I may have mentioned on other threads that I acquired an 'abandoned project' Prairie last year with which there was a boiler.Having read of Alan's problem I put the boiler in place and found that the throatplate blowdown connection does line up with the gap between the two stretchers mentioned above.
Looking at the boiler drawing,the blowdown boss seems to be in the right place,so I wonder if it is worth carrying out further checks,Alan?I guess it wouldn't be too difficult to modify the stretchers if all else fails.
Taff is quite right about the blowdown valve position on the full-size locos;the works drawing shows the valve fitted to the backhead.I've wondered why this is the case as sludge could presumably build up round the bottom of the throatplate area?
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Post by fostergp6nhp on Oct 10, 2011 17:00:21 GMT
For blowing down it would work sort of to shift a good proportion of the muck, as the water/sludge will be stirred up when in steam, but at boiler wash out the front corner mud doors would be removed along with all the other mud doors and then the muck would be shifted no problem.
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Post by Laurie_B on Oct 11, 2011 19:56:16 GMT
Presumably frequent washing out full-size boilers would have been more effective than just blowing down. I found a few detail images that might be of interest,and possibly for builders of other GWR classes. www.warrenshephard.com/detail_photographs_for_modelling.htmThe notches in the 51xx reverser quadrant look interesting.Perhaps someone could....expand........(pun intended )
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Post by alanetm on Oct 14, 2011 16:54:46 GMT
In response to Laurie B, yes the position of the connection is in the right place. The problem arises because the drawing shows a right angled connection silver soldered to the boiler and this right angled connection will not pass through the space between the frame stretchers.
What I have done is cut off the right angled connection and threaded it so it is now a bush. Now I can screw in a right angled connection after the boiler is in place.
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Post by ianholder on Oct 15, 2011 19:05:27 GMT
Nothing to do with boilers, the reversing lever catch has two spring loaded nibs in, one on each side of the lever that are independent of each other so that the lever can register with the notches on either quadrant. There are more notches in the normal running position of the lever so that you can get closer to the sort of adjustment that you get with a screw reverser in this critical area. On a drawing in Ernie Nutty's book on GWR locos in fore and back gear the notches are shown as 21, 23, 25 and 30% cut-off. You could not do this with one notch spanning both quadrants. Been looking for a drawing of this for years, regards Ian
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Post by Laurie_B on Oct 15, 2011 21:41:15 GMT
Thanks Ian for the explanation.I seem to remember Keith Wilson briefly mentioning the subject in Model Engineer a few years ago.Unfortunately there weren't many details given.Every time I've tried having a closer look on one of the preserved railways' locos,the staff there always seem very reluctant to let me on the footplate;possibly H&S rules,or as one driver explained,if they let me onboard they'd have to let everyone on!
Nice to read that you've sorted your problem Alan.The boiler I acquired had a conventional bush soldered in from new,rather than the strange arrangement shown on the drawing.
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Post by fostergp6nhp on Oct 16, 2011 9:22:46 GMT
A way around the majority of H & S bullshit is to go and have a word with the shed master to get access to a dead engine on shed. When i wanted to look at Mountaineer the staff at Boston Lodge almost fell over themselves to help even to apologising that had they had advance notice they would have got it out in the yard for me, the loco was still in the shed and penned in so photo's were very difficult. Ref the reverser catches, i had it in my mind that the catch was actually 2 separate catches but i did not post as my memory was from 30+ years ago from a footplate run Bridgnorth to Bewdley return on 5164, so i was not certain enough to post and my copy of Ernie Nutties book is out on loan so i could not check.
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jma1009
Elder Statesman
Posts: 5,896
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Post by jma1009 on Aug 20, 2014 9:54:05 GMT
apologies for resurrecting this thread but have been having a good look at Laurie_B's link to the warren shephard pics... if you have a look at www.warrenshephard.com/images/Model%20details/Large/DSCF0038.JPGyou will see that on a Pannier tank the notches on the reverser rack are as one would expect ie all in line on both sides of the rack. having spent quite a bit of time examining the fullsize reverser (on the 57XXs) and making a scale one for my 5"g version some years ago i dont follow that the reverser latch works on only one side of the rack at anyone time as this would be impossible due to the standard GWR method of making these bits - my suggestion is that the 51XX in warren shephard's pics has an 'odd' rack on one side which it ought not to have! the reverser can only be notched up where both notches align on both racks - not many positions on the lefthand rack. or have i got this totally wrong? cheers, julian
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baldric
E-xcellent poster
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Post by baldric on Aug 21, 2014 12:17:16 GMT
Julian,
Sorry, you have it wrong, on many GWR locos the reverser has 2 different sides to the rack allowing finer adjustment to the cut-off, I have no idea why a pannier doesn't. For info in the body of the catch mechanism there are 2 separate latches that are operated with a single pin, the pin is in a slot so the latches don't both have to go down together. In case you are wondering how I know, I have made replacements for a full size 72xx and looked at a 41xx, and 38xx in detail. Baldric
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