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Post by joanlluch on Nov 25, 2014 21:06:38 GMT
To Roger: SAE 660 May be indeed a good material for cylinders. There is at least one aspect where stainless may beat bronze though, it's thermal conductivity. We want heat to not get lost in the cylinder. The poor thermal conductivity of stainless may help this. Also the grade I am proposing is easy to machine. I have to check but this suggests me that such grade does not have the problems that the most common grades have.
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Post by joanlluch on Nov 25, 2014 21:18:09 GMT
Just a thought but putting aside all the good valid reasons put forward in this thread for not using SS would a stainless steel cylinder not be less efficient too. Would you not get more problems with condensation as SS is not a good conductor of heat. Another thing to consider, stainless steel and the steam locomotive appeared around the same time, certainly stainless steel was here in the early 1900's so why has it not been used before? I'm all for new ideas but when we are talking about a material that was well known during the steam era's hey day then there must be a good sound reason for not using this particular material. Pete Stainless steel being less conductive means that the material will not loose heat to the atmosphere, thus it will keep a higher temperature inside the cylinders. So in fact it will not be less efficient but quite the contrary, unless I am missing something. You will get less condensation as well for the same reason. On a full sized loco stainless could not be used because you can't make a casting out of it. On miniature however you can machine a solid block of material.
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Post by Roger on Nov 25, 2014 22:16:34 GMT
I'm not sure the conductivity of the cylinder is of much relevance except in the initial stages of starting the locomotive when condensation is going to happen in all metal cylinders. The insulation on the outside will limit the losses and they will probably all end up at pretty much the same temperature. I don't think the efficiency would be measurably different. Corrosion and bearing properties are the ones that have the greatest importance. If you can keep the Stainless Cylinders away from any other metal parts they might gall with, that ought to work. It's worth bearing in mind that Stainless of any kind is a lot tougher to machine into the form you require and you probably won't be able to cast it. Both Cast Iron and SEA660 are much eaier to get into the shape you require. That alone would put me off using it.
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Post by joanlluch on Nov 26, 2014 4:45:30 GMT
I am not posting this that often to prevent me to be titled as a fool and utterly rejected in this forums, but one of my goals is to produce a 100% stainless steel "naked" shiny locomotive. Thus my interest in studying whether such material could be used in as many parts as possible. (Please, for those who are "purists": avoid to comment if you do not like the idea)
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Post by Roger on Nov 26, 2014 7:08:31 GMT
Hopefully everyone has realised by now that you are no fool, but just have very different goals and interests to most of us. I think that Stainless Steel is not really the right material to use where there are moving parts in contact with it. I don't see why you couldn't use it externally on cleading for example on the outside of Cast Iron or Bronze Cylinders which could have Stainless Steel covers and say Bronze inserts where the piston rods come out. It's going to be difficult to stop the metal piston or valve parts from making contact though. I'm sure you'll succeed in your goal, it's just a matter or working through the issues one by one. There's going to be a limit to how much people here can help you though. The materials used conventionally have been chosen for their proven suitability and that's all that members will have experience of. I'll be very interested to see how it turns out, it's certainly a lot different to what we're used to seeing.
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Post by Deleted on Nov 26, 2014 16:17:10 GMT
I am not posting this that often to prevent me to be titled as a fool and utterly rejected in this forums, but one of my goals is to produce a 100% stainless steel "naked" shiny locomotive. Thus my interest in studying whether such material could be used in as many parts as possible. (Please, for those who are "purists": avoid to comment if you do not like the idea) ----------------------------------------------- Don't worry matey, you're obviously no fool and a loco finished in 100% stainless steel has been done quite a few times now...........As a person who wanted to go into the Research and Development side of Rail Traction Engineering, I hope I'm not deemed to be a "Purist" ?? ( A "Traditionalist" on the other hand is something entirely different...) .............. PS, DERBY went to the wall and my career went elsewhere.....
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Post by albert on Nov 26, 2014 16:28:17 GMT
Hello, This all stainless is not new, several years ago there was a stainless top motion traction engine on the circuit, it was no better than a conventional T/E, it did not look any cleaner than many others. As for thermal efficiency it was never mentioned. Albert
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Post by joanlluch on Nov 26, 2014 19:05:06 GMT
The reason I attempt to go all SS is partly emotional. I've been working all my life with this material and I know it very well. It could or not be the best on every part, but after two decades working with it I got in love with it. So there is not a real rationale behind it. I know I will have arguments with my loved SS she-mate, she has a strong character, but God, she's beautiful, and I think she may love me too. I believe I know her enough to hopefully deal with her in a successful way, but it is said that love is blind so I may utterly fail to conquer her. Time will tell, but I am not yet ready to leave my loved mate for another girl. Ultimately, my "affairs" with her with be known, so everybody will know whether this girl deserves any respect.
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Post by alanstepney on Nov 26, 2014 19:25:25 GMT
It is well over a century ago that Stainless Steel was made in commercial quantities.
At that time and for long afterwards, the very height of technology was the steam engine in its various forms. The designers, of those, the latest high-tech devices, could choose any materials they wanted, if there was any benefit to them.
They didnt use S. S.
Yes, lots experimented with it, but found no clear advantages.
I'll stick with the "conventional" materials, until or unless, someone can show me some benafits of changing.
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Post by Deleted on Nov 26, 2014 20:01:01 GMT
Does anyone remember seeing an all SS Rebuilt Scot in 3.5"g --I think ??
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Post by springcrocus on Apr 15, 2015 6:34:52 GMT
Good morning, Gentlemen I've brought this thread back to life, rather than start a new one, because sometime in the next six to eight weeks, I will be expecting to aquire the material for the cylinders on my 5" Brit. The choice will be probably be between cast iron castings, cast iron billets, gunmetal castings and gunmetal billets although I am also attracted to the mild steel with liners proposed earlier by David (vulcanbomber). I can't really think of any more viable alternatives. So, has anybody got anything to add to the discussion so far? Factors that will influence the decision include ease of machining, cost, reliability, maintenance and, of course, cost again. That's 'cause I'm skint and wooden cylinders really wont cut the mustard. As an aside, I will be putting an ad in the "Wanted" section for certain Brit castings so if you have any hiding under the bench, please have a look. Steve
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Post by Roger on Apr 15, 2015 7:27:15 GMT
Hi Steve, From what you say it sounds like you are considering machining from solid as one option. That's not for the faint hearted, there's an awful lot of material to remove and you almost certainly will have to machine it on a mandrel with multiple setups on a rotary table to be able to reach all over it. The flip side of that is that it's a very cheap way of doing it. Don't assume that the cost of a Bronze is significantly more than Cast Iron, certainly SAE660 is pretty cheap if you shop around. How good that turns out to be in the long run is hard to tell but it machines beautifully and it won't rust which is why I chose it. Here's a link for Cast Iron, and a link for the place I bought my SAE660 which cost £142.80 delivered for my two cylinders. (102mm diam x 170mm long)
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Post by ejparrott on Apr 15, 2015 8:05:38 GMT
Iron every time, unless you're looking to produce really high detail cylinders, under the cladding, where it'll never be seen again, in which case steel fab with iron liners
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Post by Deleted on Apr 15, 2015 8:35:32 GMT
On the original topic :
The currently available engineering plastics would not be suitable for cylinders on a real engine . One day maybe .
Lots of toy and demonstration engines have been made with Perspex and glass cylinders but only for occassional use at low temperatures and pressures .
Carbon-Carbon composites would work for structural things like actual cylinder blocks but they have poor wear characteristics so a liner would always be needed which leads to extra problems .
The only serious contenders for completely new cylinder materials are the ceramics - they have lots of possibilities for use with steam . I/C engines with complete ceramic cylinders or just liners have already been sucessfully built and run .
Britannia cylinders :
Realistically irons , gunmetal and bronzes as conventionally used remain the best materials to use for model cylinders . There certainly are other materials like Monel but very expensive and no advantage .
Of the simpler materials cast Aluminium Bronze cylinders would probably be best of all but expensive and difficult to machine .
I'll add one thing to the list of ways of making cylinders and that is fabrication . I've done this . Two end plates , two tubes , back flange and a few joining up bits with a bit of self jigging of the parts and a few screws and silver solder all in one heat .
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Post by Deleted on Apr 15, 2015 8:36:28 GMT
Bronze for me....details as to why are covered somewhere although not sure in which thread... some of the reasons for my particular castings were, cost, likelihood of castings being unusable if in cast iron and the fact that it's a 3 cylinder and what this would mean if the centre cylinder ever had a rust issue.
regards
Pete
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Post by Cro on Apr 15, 2015 8:58:20 GMT
Steve,
A friend of mine has far to many Brits or bits for them, just selling the one he has only just finished, I have dropped him a text to see if he has anything lying around.
I personally would go bronze for the same reasons Pete has stated above.
Adam
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Post by Shawki Shlemon on Apr 15, 2015 9:18:06 GMT
Maaaany years ago I saw a full SS locomotive in 7.25" G , I can't remember what it was but I do remember it had problems and it couldn't complete one round on the track , I am sure it was NOT because of the materials , it was a visiting loco and I have never seen it again , the owner was a friend of the president of the club at the time , the loco was new and it was a trial run . To me it looked strange but quite OK , different , this is a hobby anything goes .I am not sure whether cylinders were also in SS . My opinion if that is what you want to do , have a go , follow your heart . I for one will be interested to see how it goes .
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Post by andyhigham on Apr 15, 2015 10:33:53 GMT
The best material is cast iron with cast iron pistons and piston rings. The only drawback with cast iron is rust. (after steaming squirt some oil down the blast pipe and push the loco forwards in reverse gear and vice versa) Bronze/gunmetal etc are non rusting but problems arise selecting suitable piston rings and piston valve seals. An alternative thought would be to speak to one of the companies that renovate 2 stroke motorcycle cylinders. They apply a "Nikasil" plating on the cylinder bore, this is a hard wearing chrome like finish and cast iron rings work perfectly with it
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Post by Deleted on Apr 15, 2015 11:35:37 GMT
Hi Andy..an interesting idea but i'm not sure that you can do this for the materials that we normally use? I stand to be corrected but I thought that nikasil or the other variants, alusil and lockasil are only used to coat aluminium cylinders, not sure that this can be used on cast iron etc. Mind you i guess you could always make your cylinders from aluminium and then get them coated, if this is possible you may have discovered a way of getting a more efficient steam locomotive due to the thermal properties of aluminium...There are issues though...any problems with the bore and it's back to the drawing board as honing this material is probably beyond the home workshop, not impossible but the coating is very thin and there's no room for error, also you won't be able to use a normal honing tool as you need special cutting stones and paste. However yes if you could do this you would have a very hard wearing bore that runs very nicely with cast iron rings, the chances of wearing the bore in our environment are just about impossible unless you get grit or such inside. My Porsche engine that i'm currently rebuilding is Alusil, not a coating as such as Porsche cast the silicon into the block and then etch the bore to burn away the alloy ready for honing leaving the ultra hard crystals as the only contact with the piston rings. BTW the early nikasil engines did have problems with seizing up due to rust...I don't know the details behind this though but it's known about in Porsche circles.
Pete
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