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Post by delaplume on Oct 26, 2019 10:09:34 GMT
Just a further thought on that upstand idea}------
As that main safety valve body is in direct contact with the boiler pressure vessel it gets very hot when the loco. is in use.....Even when standing still in the station or in the yard at an MPD....
I can assure you from many years on the cleaning roster that it's bloomin hot up there, enough to eventually evaporate any condensate water that might have been contained therein........
It sort of leaves an impression on you, one might say !!! (smiley emoticon)
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 26, 2019 10:46:38 GMT
Alan What do you think the chances are of persuading Roger to repeat the safety valve cover exercise but in a profile to suit 'Bear'? Pretty slim I would imagine........He's got enough on his plate at the moment, what with this 15xx, his own job ----- and something called "A family" ....more's the pity...... However all is not lost as The Bear's safety valve unit is / was from a Star ---- and later on a Castle... I used the Peter Riche 5" Castle drawings for the mounting ring fitted on my boiler but I've yet to produce the actual valve body itself... For a while I had a 2nd grade bonnet casting from Polly which looked identical to those 3D drawings apart from the base-line which was almost horizontal......Alas, in a moment of Club friendship I donated it to a very needy Manor.... Full marks to Roger for a machining tour de force but I lack the skills and the equipment to follow his method, and I know I'm not alone! However I don't think a casting is a great help for this item, because you are still left with the problem of getting it to sit nicely on top of the boiler; of machining it very thin (and thus chucking it securely) to get clearance inside; and then of profiling the outside to a nice polish free of blowholes... and even if you achieve all this, it still doesn't look like the real thing because it lacks the beaded edges and (yes) those slight imperfections that tell the world it is a proper beaten product. Beating it from flat like Swindon did is impractical in such a small item I think, but the method I hope to use is spinning it as two cones, joined by an internal sleeve as described decades ago by Roy Amsbury (Model Engineer 2.2.73). As an alternative, for those who don't like spinning, Peter Stevenson described a method of forming from a rolled cone in EiM Sept 2011. Wish me luck! -Gary
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Post by delaplume on Oct 26, 2019 13:44:40 GMT
Hi Gary,
Quote}--"Full marks to Roger for a machining tour de force but I lack the skills and the equipment to follow his method, and I know I'm not alone! However I don't think a casting is a great help for this item, because you are still left with the problem of getting it to sit nicely on top of the boiler; of machining it very thin (and thus chucking it securely) to get clearance inside; and then of profiling the outside to a nice polish free of blowholes... and even if you achieve all this, it still doesn't look like the real thing because it lacks the beaded edges and (yes) those slight imperfections that tell the world it is a proper beaten product".
I managed it like this---
After some initial preparations}---To hold it I soft-soldered the top end onto a stub of faced-off round mild steel bar--- then centered in a 4-jaw independent chuck.....For cutting I used a hand-held Dremel Mini-Drill along with the appropiate stones and emery wheels....and partly rotated from time to time by hand... NO POWER from the lathe AT ANY TIME !!
Polishing was by hand and successive useage of 200 and 400 grit paper etc....although the job was made fairly easy as Polly supplied the casting already slightly polished in the first place...
As there wasn't any power turning involved I could remove, test onto the Bear's boiler, then replace without the need to re-centre too accurately....
Incidentally I quite often made use of soft soldering as a holding agent at the SVR, for example when machining new piston rod metallic packing halves...
As I mentioned earlier I "donated" that particular bonnet to a very poorly Manor.....I wonder if Polly have any more available ??
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Post by Roger on Oct 26, 2019 22:01:00 GMT
This is my solution to the deflector that's been suggested for the safety valve body. I don't really want to Silver or Soft Solder to the existing body unless there's no other way, so this fits onto the flat face of the body before the threaded rods are attached. Those will have locknuts that press down on this to hold it in place. Looking from the top, it looks like the casting is what you're seeing because I've included those features in the base of the deflector. There has to be a clearance for them underneath anyway. Deflector sleeve by Timothy Froud, on Flickr This is how it looks in situ, with a gasket under it to make the seal. Assembly with deflector sleeve by Timothy Froud, on Flickr So this is the first operation to machine the deflector from a piece of 25mm Brass which is the finished size. Here I've added a square to the top, the sole purpose of which is to hold enable the top and bottom machining to be located radially. 20191026_132721 by Timothy Froud, on Flickr That's done by holding it by the flats in the vice for machining the underside. 20191026_144757 by Timothy Froud, on Flickr A quick check to see that it clears the curved tubes in the 'casting'.... 20191026_144806 by Timothy Froud, on Flickr ... then adding the clearance holes. 20191026_145459 by Timothy Froud, on Flickr The rotary table can now hold the piece the other way up, and I can clock the side, turning the table to get it true to the square. 20191026_150415 by Timothy Froud, on Flickr Once the middle was found, the square was machined off since it's in the way now. 20191026_151215 by Timothy Froud, on Flickr I've used a Horizontal Roughing operation to remove the bulk of the middle in 0.5mm cuts. I can't hold this too tightly else it's going to deform when the middle is removed. 20191026_202839 by Timothy Froud, on Flickr A 3mm Radius mill with a 0.5mm corner radius is being used here with a Radial Finishing operation, starting from the top edge and lifting at the middle. I don't want this going back, taking a cut on the vertical side from the inside because that's going to end in tears. 20191026_204141 by Timothy Froud, on Flickr You can just make out that half of the curved inside detail has been cleaned up, with the staircase still showing on the left. 20191026_215410 by Timothy Froud, on Flickr That's got another couple of hours to run, so turning to the top feed body again, here are the studs going in. I'm using the bung I made ages ago to stop anything falling into the boiler. The back right stud has a pair of nuts locked onto it so I can tighten the stud down. the item on the left is the colour coded box spanner made from Silver Steel. 20191026_222827 by Timothy Froud, on Flickr This looks a lot more compact now, and actually more like the real thing. 20191026_223629 by Timothy Froud, on Flickr And best of all, the cover now clears the nuts and the edge of the flange. A lot of effort, but well worth the result. 20191026_223646 by Timothy Froud, on Flickr The feed tubes had to be annealed before I could get them back into shape. 20191026_204609 by Timothy Froud, on Flickr
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 26, 2019 23:29:13 GMT
Hi Gary, Quote}--"Full marks to Roger for a machining tour de force but I lack the skills and the equipment to follow his method, and I know I'm not alone! However I don't think a casting is a great help for this item, because you are still left with the problem of getting it to sit nicely on top of the boiler; of machining it very thin (and thus chucking it securely) to get clearance inside; and then of profiling the outside to a nice polish free of blowholes... and even if you achieve all this, it still doesn't look like the real thing because it lacks the beaded edges and (yes) those slight imperfections that tell the world it is a proper beaten product". I managed it like this--- After some initial preparations}---To hold it I soft-soldered the top end onto a stub of faced-off round mild steel bar--- then centered in a 4-jaw independent chuck.....For cutting I used a hand-held Dremel Mini-Drill along with the appropiate stones and emery wheels....and partly rotated from time to time by hand... NO POWER from the lathe AT ANY TIME !! Polishing was by hand and successive useage of 200 and 400 grit paper etc....although the job was made fairly easy as Polly supplied the casting already slightly polished in the first place... As there wasn't any power turning involved I could remove, test onto the Bear's boiler, then replace without the need to re-centre too accurately.... Incidentally I quite often made use of soft soldering as a holding agent at the SVR, for example when machining new piston rod metallic packing halves... As I mentioned earlier I "donated" that particular bonnet to a very poorly Manor.....I wonder if Polly have any more available ?? That would work in 5" gauge, where the SV bonnet is like a large thimble. I wouldn't fancy it in 7 ¼" where it is more like a small teacup, lots of hard filing! Maybe a Black and Decker instead of a Dremel? ;-) As for Polly, they have a lot of GWR castings in their Practical Scale range, you can only ask... -Gary
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Post by delaplume on Oct 26, 2019 23:39:19 GMT
Hi Gary,
Yes, it's from their Practical Scale range that they supply Peter Riche's Castle drawings, castings etc.....I use them a lot for the majority of The Bear's items...
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Post by Roger on Oct 27, 2019 12:31:41 GMT
This is how the deflector looks as machined... 20191027_085005 by Timothy Froud, on Flickr ... and it fits like a glove, so I'm really pleased with it. 20191027_090332 by Timothy Froud, on Flickr I was going to use a gasket, but instead I'm decided to use Loctite 574 Flange Sealant because I want to follow up on Alan's suggestion to use spacers to set the Safety valve pressure. 20191027_110957 by Timothy Froud, on Flickr I made up an adaptor with an M6 thread to attach the air line and a regulator so I can check the opening and closing pressures. 20191027_105854 by Timothy Froud, on Flickr Armed with that information I made some Phosphor Bronze sleeves to go under the spring retainers and set the characteristics as follows... Initial opening 85 PSI Maximum pressure with the regulator at line pressure 92PSI Closing pressure 82PSI Now these might just be a little on the low side, but it's a good starting point. Shaving 0.1mm off the spacer appears to result in about 2-3PSI increase on the opening and closing pressure. Anyway, I think it's a good place to leave that and move on to the next task. At least I know there's no way I can get to dangerously high pressures. 20191027_121815 by Timothy Froud, on Flickr
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 27, 2019 18:13:07 GMT
That’s an exceptionally neat solution Roger, well done! - Gary
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Post by Roger on Oct 27, 2019 18:36:40 GMT
Thanks Gary, I'm glad you like it. This is the bonnet from another GWR locomotive that was on the workshop floor at the SVR when I visited, and it seems likely that the detail on the bottom of the shoulders is the same on 1501. 20140204_114256 by Roger Froud, on Flickr This is the clearest shot I've got, and it certainly looks that way. So far I've not really looked that closely at the entry of the pipe, so there's going to be a bit more modelling of that required as my current one doesn't look like that. IMG_1414 by Roger Froud, on Flickr Anyway, either way, the pipe needs to go through the tank and join up with the top feed, so here's the first attempt as doing that. 20191027_173458 by Timothy Froud, on Flickr 20191027_173600 by Timothy Froud, on Flickr There's no way I'm going to get that fitting around all the tight bends, so I'm putting it on now and modifying the bending fixtures to accommodate it. 20191027_175255 by Timothy Froud, on Flickr This is a quick and dirty print of the LH shoulder to see if I've got the flange somewhere near right. 20191027_174412 by Timothy Froud, on Flickr There's more support material than there is in the whole part! 20191027_181201 by Timothy Froud, on Flickr It seems to fit reasonably well, so I now need to concentrate on getting that exit right. The pipe is way over scale, but there's no way around that if it's going to work. 20191027_182112 by Timothy Froud, on Flickr This fits really well, even though the print is a mess. 20191027_182131 by Timothy Froud, on Flickr
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Post by mugbuilder on Oct 27, 2019 18:48:06 GMT
That assembly is an anmazing piece of work. Something that I would be reluctant to try myself. Very well done, Barry.
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 27, 2019 19:00:16 GMT
Frustrating isn’t it? You could model that great gap exactly, between the bottom of the shoulders and the boiler cleading, and somebody is bound to say (or think) “look at that geat ugly gap, surely he could have done better than that!” Some aspects of Swindon build were decidedly agricultural, though ‘tis sacrilege to say so...
Gary
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Post by Roger on Oct 27, 2019 19:29:43 GMT
Frustrating isn’t it? You could model that great gap exactly, between the bottom of the shoulders and the boiler cleading, and somebody is bound to say (or think) “look at that geat ugly gap, surely he could have done better than that!” Some aspects of Swindon build were decidedly agricultural, though ‘tis sacrilege to say so... Gary Exactly so, it's always a compromise so it's best just to please myself really. These things are a real pain to model, there are no drawings of the cross sections so it's down to guesswork and lots of checking the photos. I think this part is impossible to machine into all of the corners, but hopefully it will be feasible to do something. We'll see. Until it's finally modelled it's hard to know what the issues will be.
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Post by Roger on Oct 27, 2019 19:36:53 GMT
That assembly is an anmazing piece of work. Something that I would be reluctant to try myself. Very well done, Barry. Thanks Barry, I'm really enjoying seeing all of the locomotives you've built. I don't know how you've found the time to do all that and with such detail too. In reality, it's the equipment and software that are the game changers. When you can sculp parts out of solid without the constraints of traditional methods, life is much easier.
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Post by ettingtonliam on Oct 27, 2019 20:24:46 GMT
Gary As Belfast folk are prone to say about 'Titanic' -- 'It was fine when it left Belfast' then possibly old Swindon folk, shown a photo of 1501 now would say 'It didn't have those great big gaps when it left here'
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 27, 2019 23:23:58 GMT
Gary As Belfast folk are prone to say about 'Titanic' -- 'It was fine when it left Belfast' then possibly old Swindon folk, shown a photo of 1501 now would say 'It didn't have those great big gaps when it left here' Indeed... but there was that infamous bunker fire Mr Belfast, when did that start? As for Swindon, I have a photo of 1504 in BR service, which I’ve just looked at closely, and yes, that ugly gap is there too. Looks like the buck stops in Wiltshire and we can’t blame the SVR nor the NCB for that matter! So if Roger feels obliged to make a better-looking fit for appearances’ sake, we will all have something to criticise (for once!) Gary
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jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Oct 28, 2019 0:18:22 GMT
I don't think Roger has posted on here the original works drawings for the safety cover that he has copied. I have done a search on here and via emails from the late Bob Youldon, so can only go by what I perceive to be correct via numerous drawings and pics I have for older GWR locos.
I have yet to be assured that the safety valve top is the correct diameter or the shape of same. To my mind it appears to be too short in diameter at the top, and the flare too gentle.
I assume Roger wants to recreate the 15XX as it was in BR days rather than as acquired by the SVR with quite a lot of spares from industrial usage.
Happy to get shot down on all of this of course, and no criticism implied of Roger's remarkable machining skills and tooling.
Cheers,
Julian
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Post by Roger on Oct 28, 2019 8:13:22 GMT
I don't think Roger has posted on here the original works drawings for the safety cover that he has copied. I have done a search on here and via emails from the late Bob Youldon, so can only go by what I perceive to be correct via numerous drawings and pics I have for older GWR locos. I have yet to be assured that the safety valve top is the correct diameter or the shape of same. To my mind it appears to be too short in diameter at the top, and the flare too gentle. I assume Roger wants to recreate the 15XX as it was in BR days rather than as acquired by the SVR with quite a lot of spares from industrial usage. Happy to get shot down on all of this of course, and no criticism implied of Roger's remarkable machining skills and tooling. Cheers, Julian Hi Julian, I haven't posted the Works Drawings because of copyright issues that might arise. You're quite right that the final diameter of the outside edge is smaller than it's supposed to be, by quite a lot as it turns out. The drawing scales to 40.458mm whereas mine ends up at 35.11mm. All the other dimensions are as they should be. The issue with the top is that the edge ends up wafer thin if you truly follow the drawing, and I don't think it's feasible to have a rolled edge appearance without the rolled edge being way over scale. So what I elected to do was to go for a rolled edge but that's pulled the outside diameter in to achieve it. The construction was exactly to the drawing, but that radius pulls in the outer edge somewhat, if that makes sense. If you look at the pictures of 1501 I posted above, I don't think they're to the works drawing either. To my eyes the top looks much more like what I've made because the bottom looks large in proportion to the top. It's hard to be sure of anything really without measuring what's actually on there. Personally, I'm very happy with it, I don't think many people would spot what you have with your Eagle eyes! It's all a compromise, and I'm not making a super scale model in any case. It's easy to become too obsessed with these things, I'd never finish it if I kept going back to make minor changes that most people, including myself, wouldn't notice. There are many places where it's not truly to the Works Drawings, after all it started life as SPEEDY, and without starting from frames made to the Works Drawings, there's no way to make it exactly right.
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Post by ettingtonliam on Oct 28, 2019 9:27:08 GMT
Gary As Belfast folk are prone to say about 'Titanic' -- 'It was fine when it left Belfast' then possibly old Swindon folk, shown a photo of 1501 now would say 'It didn't have those great big gaps when it left here' Indeed... but there was that infamous bunker fire Mr Belfast, when did that start? As for Swindon, I have a photo of 1504 in BR service, which I’ve just looked at closely, and yes, that ugly gap is there too. Looks like the buck stops in Wiltshire and we can’t blame the SVR nor the NCB for that matter! So if Roger feels obliged to make a better-looking fit for appearances’ sake, we will all have something to criticise (for once!) Gary My point is, at what point in BR service was your photo of 1504 taken? Was it straight out of the Swindon factory, or after it had been in the hands of the running sheds for a while. I reckon that the safety valve cover and clack box covers were probably taken off fairly regularly for attention to the bits they covered, and the hard pressed fitters wouldn't be too fastidious about how well they fitted afterwards. They might have been more careful with a King, which would be in the public eye, but not with a lowly shunter. Titanic's bunker fire? Its an arguable point if indeed there ever was one. There was a coal strike in early 1912, resulting in a shortage of bulk coal supplies for shipping. It was over by the beginning of April, but Titanic was only coaled for the voyage at the very last minute in Southampton, and one suggestion is that this hurried operation with dry dusty coal resulted in a smouldering fire, which anyway played no part in the iceberg strike and its aftermath. Not in Belfast, no sir!
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Post by delaplume on Oct 28, 2019 11:53:02 GMT
Hello all, Bearing in mind that these bonnets sit on top of a GWR "Standard" boiler I thought this might make for some light, bed-time reading ??--------------------------------> www.devboats.co.uk/gwdrawings/gwrstandardboilers.php <-------- Hi Roger, Have another look at that bonnet photo shown inside the SVR running shed......notice that the bottom of the shoulder is almost pointing vertically downwards, indicating that it came off a boiler without a water tank nearby ie}-- a tender loco. where the feedpipe follows the curve of the boiler However, on 1501's photo the same part is almost at 90 degrees, thus allowing the feedpipe to follow the horizontal top of the water tank, which is almost at the same height as the bottom of the safety valve.... a feature that you have modeled quite well I would say !! I would also second the approach that says}--- "This is how it looks in service to-day".....because a).The loco is always available for photos or checking details etc BUT.... b).The best bit is it stops those Purists and Rivet Counters in their tracks.... You made a good point by saying that your model initially was a Speedy....With a nod to William Stroudley perhaps you can market this version as an "Improved machinist's 15xx" ??...LoL !! Keep it up, matey !!.........It's an inspiration to us all ps}---- Posty has just arrived with a box of fresh Microns...I'm going to apply them to my old Chester Craftsman lathe and hope !! Cheers Alan
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Oct 28, 2019 19:34:40 GMT
Indeed... but there was that infamous bunker fire Mr Belfast, when did that start? As for Swindon, I have a photo of 1504 in BR service, which I’ve just looked at closely, and yes, that ugly gap is there too. Looks like the buck stops in Wiltshire and we can’t blame the SVR nor the NCB for that matter! So if Roger feels obliged to make a better-looking fit for appearances’ sake, we will all have something to criticise (for once!) Gary My point is, at what point in BR service was your photo of 1504 taken? Was it straight out of the Swindon factory, or after it had been in the hands of the running sheds for a while. I reckon that the safety valve cover and clack box covers were probably taken off fairly regularly for attention to the bits they covered, and the hard pressed fitters wouldn't be too fastidious about how well they fitted afterwards. They might have been more careful with a King, which would be in the public eye, but not with a lowly shunter. Titanic's bunker fire? Its an arguable point if indeed there ever was one. There was a coal strike in early 1912, resulting in a shortage of bulk coal supplies for shipping. It was over by the beginning of April, but Titanic was only coaled for the voyage at the very last minute in Southampton, and one suggestion is that this hurried operation with dry dusty coal resulted in a smouldering fire, which anyway played no part in the iceberg strike and its aftermath. Not in Belfast, no sir! Hi Ettingtonliam Majestically avoiding going Titanically off-topic, I can't say when my photo of 1504 was taken, though I don't think it would take us very far forward as the 15xx had rather short operating lives in BR service. Judging from the photos they did not get a lot of love and affection in the sheds either, so your theory of flinging the bits back together after a quick service makes perfect sense. Whether the fit was better in 'ex-works' condition would be much harder to prove. The dilemma for us making models of them, is which do you follow? The photographic evidence of a rather unlovely fit in service condition, or an optimistic wish that they might have (briefly) looked a bit better when they were new? We will all have our own opinions, and in the end we will do what satisfies ourselves, but it isn't a particularly easy call. For some of us (not Roger of course) it could be a handy excuse... -Gary
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