johnd
Part of the e-furniture
Posts: 281
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Post by johnd on Mar 9, 2021 17:04:52 GMT
Pete, Just to confirm that on my valves the chamfers do overlap but because they are only a few thou deep i think it probably doesn’t have any effect on strength. Gordon Smith at the time i spoke to him said that in his experiments it did make a difference. I have just remembered that another thing we talked about was the fit and finish of the stem that passes through the adjusters. He said that the stem should have a high finish and the just enough clearance for a smooth sliding fit. He did dozens of experiments over a long time, i went to two of his lectures and found him fascinating to talk to.
Daggers
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nonort
Part of the e-furniture
If all the worlds a Stage someone's nicked the Horses
Posts: 277
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Post by nonort on Mar 9, 2021 20:01:13 GMT
Just a thought why not make the valves to the Gordon Smith drawing. Then add chimneys to them to clear the tank. The spring should never touch the spindle of the valve. Also I have made several sets of these and found that with all the bits made as drawn the adjusting nuts are almost unnecessary as I screw them down so they are level with the top of the body the rate of the spring is at its most workable point and screwing the adjuster in and out makes very little difference. They are I believe drawn out to run at one hundred PSI.
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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 Mar 9, 2021 21:14:37 GMT
Pete, This is an intuitive rather than an expert response, but it strikes me that if the valve is opening more efficiently (as it probably is with any pop action) the amount of steam needing to be released in a given time through the holes in the cap will be greater, necessitating a greater area. So the comparison with the previous situation may not be wholly valid. I think the chamfers around the holes are useful to ease the steam flow and I can't see that they would diminish the strength of the top cap significantly? Malcolm I can give it a try! Pete.
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Post by suctionhose on Mar 10, 2021 1:44:58 GMT
[quote author=" smallbrother" With types (b) and (d), what is the object below the guide in the bore? Pete.[/quote] Pete, Out of courtesy I should answer your question myself. Yes type b and d show wing valves with a guide in the hole below seat. The wings can three in number with advantage. The bore dia should be increased to an equivalent area to compensate for area taken up by the wings.
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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 Mar 10, 2021 10:06:16 GMT
Anyone have a drawing of these wing valves?
Pete.
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Post by suctionhose on Mar 11, 2021 8:31:05 GMT
No drawings. Varies with bore. Made by plunging slot drill in from end. Not essential. Balls are fine.
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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 Mar 17, 2021 9:06:37 GMT
Well I tried my latest version and unfortunately no improvement. I wasn't looking for perfection but was hoping they would be better than the originals.
Rather disappointed and I think it shows (once again) there are some things I can do and some that would take me more patience, perseverance and time than I feel the job is worth. I have other pursuits I can get on with which involve much less frustration than this and I need a balance of things I can do easily and things that I find hard.
I have an offer from someone to make me some which is at a very reasonable price so I am going to take that up.
I can get back to other more productive workshop tasks. I have the Juliet build which is very slow but I seem to get there eventually with the stages met so far. I also intend to sell my Polly 1 loco which needs a bit of a tidy up and new certificates.
Thanks for the terrific advice as always but I have flogged this horse enough for the time being.
Onward and upward!
Pete.
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,907
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Post by JonL on Mar 17, 2021 21:09:03 GMT
I suspect that some items have reached their peak evolution after all these years, unless Roger is going to start doing lab experiments on these too! I aspire to work at your level; don't be too hard on yourself!
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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 Mar 18, 2021 8:43:29 GMT
I suspect that some items have reached their peak evolution after all these years, unless Roger is going to start doing lab experiments on these too! I aspire to work at your level; don't be too hard on yourself! Thank you! Sometimes you've got to be a realist and then you don't beat yourself up. The more trials and tribulations I go through I just see how good the top builders are. There is another thread going on choosing a model to build. Most of the advice is to choose the model you really like. That would be crazy in my situation. As with all things, we can't all be Lennon & McCartney! I went out the workshop late last night and started taking the screws off for the inner dome. I noticed a slight leak under steam. Anyway, 2 screws are not having it. So there's another little challenge for me. The more you do the better you get. None of it is wasted as far as I am concerned. Fortunately I have other interests where I know what I'm doing. I like having the balance. Pete.
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timb
Statesman
Posts: 512
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Post by timb on Mar 18, 2021 12:30:33 GMT
What is that saying, 'Change the things you can, learn to live with those you cannot'?
Something like that...
Tim
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on Mar 18, 2021 14:14:06 GMT
And have the wisdom to know which are which!
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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 Apr 14, 2021 11:24:01 GMT
I ordered 2 ready made valves from Blackgates.
Just finished testing them now. Crickey, do they pass some steam or what?!?
Tiny holes in the adjusters but they coped with the blower full blast no problem whatsoever.
Really pleased to have found a solution.
Just got to make some simple extensions now so I can put the saddle tank back on.
Pete.
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Post by coniston on Apr 14, 2021 20:17:28 GMT
Excellent Pete, glad you got it sorted.
Chris
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smallbrother
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Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Apr 16, 2021 17:23:15 GMT
Extensions duly made.
Wrong thread in one end...............arghhhhhh.
Beer o'clock.
Pete.
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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 May 13, 2021 9:37:07 GMT
I found one of the commercial safety valves was prone to buzzing.
I'm sure I read about this on the SV info kindly sent to me but can't find it.
Can anyone advise what would cause this please?
Pete.
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darrene
Part of the e-furniture
Posts: 440
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Post by darrene on May 13, 2021 14:02:18 GMT
On a side note, I was interested to read in the article about putting a drop of oil on the top of the valve. I'd noted just that advice in a video yesterday but hadn't heard of it before that. Is it a common practice?
Darren
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stevep
Elder Statesman
Posts: 1,070
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Post by stevep on May 13, 2021 14:49:36 GMT
I think it was a common practice when safety valve springs were wound up from piano wire, as it stopped them rusting.
Using stainless springs probably means the practice is obsolete - but I still do it! (There again, that speaks volumes).
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Post by ettingtonliam on May 13, 2021 17:02:43 GMT
I don't know about safety valves, but I had a hand pump that buzzed which turned out to be the one of the ball valves bouncing. I think I cured it by restricting the ball travel but that probably isn't appropriate for a safety valve.
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weary
Part of the e-furniture
Posts: 290
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Post by weary on May 13, 2021 18:15:07 GMT
Pete,
Am making an assumption about the design of safety-valve that you have fitted, so bear with me ......
Whilst your safety valve is 'buzzing' can you firmly touch the lifted valve guide-rod sticking up above the top with a piece of thin rod or rigid wire - apply pressure sideways; & if you do-so does the buzzing stop? If that eliminates the buzzing it may indicate that your valve guide-rod is just a little too slack in the hole in the top of the safety-valve and can allow vibration creating the 'buzz'. Easiest solution is smaller guide-hole! There are some other possibilities for the buzzing but maybe look at that first as it is a simple diagnostic/eliminator test.
Regards, Phil
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Post by suctionhose on May 14, 2021 2:53:33 GMT
I found one of the commercial safety valves was prone to buzzing. I'm sure I read about this on the SV info kindly sent to me but can't find it. Can anyone advise what would cause this please? Pete. The cause of buzzing is that the outlet holes to atmosphere are too small / partly covered by the spring generating back pressure in the body of the valve. This causes the valve to open and close at at a high frequency which is the buzz. In my own experiments to overcome this exact problem, I concluded the outlet to atmosphere must have an area equal to 150% of the valve bore. A valve of my own making had the buzz. I changed every possible thing (springs, seat types, clearances, everything) to no avail. I did the calc's. Outlet area was 130% from memory. Added one hole - in anger, with a pistol drill, while in steam - and problem solved! Since then, I have made many valves of different styles. It is a peculiar obsession of mine. I still stand by the 150% relationship.
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