Minnie Cylinder block

[Richard ParsonsParticipant @richardparsons61721]

Aluminium Cylinders.

Can any one help, point out problems I will have or offer useful comments?

I want to build a ME Minnie Traction Engine.  Because of chronic shortage of material over here in lace w:st=”on”>Hungarylace>, I will have to use aluminium, probably hard Dural as I have got a lump of it, for the cylinder block unit.  The cost of the bronze castings is quadrupled by postage etc.  All too often stuff does not arrive or take months.  I think this due to a shortage of ‘cleft sticks’.

I think this will work if I use solid PTFE pistons reinforced with alloy which will not touch the cylinder walls.

According to Corning Dow, PTFE softens at about 250 ºC and melts about 280ºC.

The cylinder on the Minnie is design with a steam jacket around the cylinder.  The cylinder block also acts as the steam collector from the boiler.  So the maximum temperature of the cylinder will be that of wet steam in the boiler.  Superheating with this sort of design is a non-starter.  According to my steam tables these temperatures will be: –

• At 50 PSI this is about 138 ºC,
• At 80 PSI it is 155 ºC,
• At 100 PSI it is about 164 ºC.

I expect to run the boiler at the design pressure of 50 PSI which has a temperature well under the softening point of PTFE.

The valve system will probably be PTFE piston valves again running in a Dural sleeve. 

The major problem is the sealing of the alloy cylinder and valve sleeve into the alloy block.  With bronze cylinder castings they are sweated in with soft solder.  The cylinder and valve guides will be bronze inserts etc.

I ride a little 50cc moped whose cylinders are some form of hard chromed ‘monkey metal’.  It has done well over 5,000 miles.

By the way Thanks to the editor I do not have to unpack and search some 40 black sack containing my copies of ME dating back to the mid-60s.

[Richard ParsonsParticipant @richardparsons61721]

[JasonBModerator @jasonb]

The only problem you may have is the cylinder expanding with temp and giving a poor fit to the piston and possible galvanic attack between the copper and alloy.

 

Can you not source a lump of cast iron and loctite or shrink fit  the cylinder liner into that, the liner could be bronze or iron, then use a dural piston as this will give smoother running due to the lighter weight.

 

Jason

[Keith Wardill 1Participant @keithwardill1]

Hi, Richard,

 

There is a construction article by Rex Tingey starting in the July 1979 issue of Model Mechanics, which is downloadable from this ME site. This uses an engine of Mr Tingeys own design, with a form of ‘sleeve valve’ instead of conventional gear. This consists of a Dural sleeve sliding in a brass outer cylinder, and the (brass) piston slides inside the Dural sleeve. (Sorry if this is unclear – see the drawings in the mag). 

 

The engine runs at 40 psi, so the use of brass is probably OK, but would not be recommended for the higher pressures in Minnie – however, the information about the Dural cylinder, and a suitable piston may be of some help.

 

Incidentally, I live in Romania, (not too far from the Hungarian border) and have found a metal dealer near me who stocks all sorts of odds & sods. I found a 10cm x 30cm rod of PTFE, which cost me 30 Lei (about 7 Euros). He has some pieces of what he calls ‘Bronz’ – but unfortunately the Romanian for brass is ….Bronz!. However, he has also some large pieces of what is almost certainly brass, and it is a slightly different colour from the ‘Bronz’ – one of his employees insists the ‘Bronz’ is phosphor bronze. If you (or anyone else) knows a way to test for PB, then I will take another look – if suitable, maybe the postage from Romania to Hungary will be less than the piratical British postal system (If Hungary is your location – strange e-mail)

 

 Alternatively – I ordered a 1.2 kg package of metal from UK, and was quoted postage of ‘about 30 pounds’ – I had it sent to a friend in UK for a fiver, who sent it on to me, also for a fiver. I also order stuff from Germany, at fairly reasonable postal charges, so go figure how the UK companies work out their pricingl  (I know a UK book company selling the latest books at a discount, who mails world-wide for free).

 

Has Hungary got people who can certify/insure boilers for public use? – there seems to be no system in Romania.

 

Good Luck – Keith

[Richard ParsonsParticipant @richardparsons61721]

Hi Keith

Thanks for the prompt reply.  Yes I am ‘next door’.  I live on the Southern great planes in ‘Mesopotamia’ the land between the rivers (Duna –Danube- and lace w:st=”on”>Tiszalace>).  There is some sort of a problem with copying the word ‘lace w:st=”on”>Hungarylace>’ so I will call the place Magyarország instead and see if that works.  3 years ago some gents from ‘somewhere East of Suez’ turned up with suitcases full of cash. If there is something no Hungarian can resist is a suitcases full of cash.  The cleared out all the stockholders, autosbonotok, junk yards and swept the place clean.  Now all you can get is ‘structural steel’.  Copper is impossible because the ‘local didcoys’ keep, ‘liberating’ the overhead conductors from the railways (and from unfinished power lines).  It seems to be a little habit of theirs.

As for Phosphor bronze I have some kilos of it –I brought some 780 kg of mixed metals from the lace w:st=”on”>U.K.lace> including 50 odd kg of assorted silver steel.

How to tell PB from brass or Gunmetal.  Brass always turns with a fine swaff, it stays yellow.  Gunmetal turns –with a sharp tool- giving fine spirals and PB in little lunate shape chips.  I am going to try put up some photos if I can.

PB is or was usually cast as a bar and has a rough irregular surface.  After a day or so freshly turned PB takes on a reddish tinge (or my bits do).  By the way does the stuff feel greasy and have a tendency to go green? If so it might be ‘Glacier Metal’ and is wizard stuff for bearings.  PB can also feel slightly slippery and is generally harder than brass.  Hope this helps.

JasonB

Many thanks I do not think I will get galvanic action.  The boiler will have to be stainless steel if the local manufacturer is still in business.  I have not been over there since last winter and he may have ‘gone’.  I am also investigating something I saw when I opened a tin of tomatoes yesterday.

Best regards

Dick Parsons

[Keith Wardill 1Participant @keithwardill1]

Hi again, Richard,

 

 I am near Arad, about 40k from the western border of Romania – as you say, there is some problem with the e-mail (I can see this in the post – ‘lace w:st=”on”>Hungarylace>&#8217.

 

Google Earth doesn’t know where Magyarország is, so I’ll take a look at a map later.

 

Sounds like you maybe got a bargain (?) with the metal – how did you get 750 kg home?.

I think maybe I didn’t make myself too clear about testing PB – I know about the machining effects, but the stuff I want to test is in a store, so I guess they won’t be too happy with me trying to machine it. I was hoping (against hope), that someone knew a simple ‘on-site’ test.  Maybe I’ll buy a bit to test. All the pieces are smooth, apparently not cast, which may be an indication they are not PB, as you say. However, I have a bar of PB at home which is also smooth, bought at a metal dealers in Germany.

 

Keep us updated with your progress, because this sounds like it could be a unique traction engine – stainless boiler, dural cylinders and PTFE pistons.

 

All the best – Keith.

[VersabossParticipant @versaboss]

Yes, Keith, there is something called ‘drawn phos. bronze’. Mostly in the smaller dimensions, but I would not dare to give a limiting number.

Although I admit that I sometimes also have troubles in distinguishing brass and bronze, I think when you would use a clean, blank piece of real brass and compares this with the stuff in the shop, you would see the difference. But naturally this means to have something first..

Maybe you can convince one of the local trumpet players (there is one in every Romanian village I believe) to bring his instrument in the shop, and you give it then (the instrument I mean) a good Brasso treatment before making the comparison  ! (just joking)

Greetings, Hansrudolf

[Richard ParsonsParticipant @richardparsons61721]

 

Hi there Keith, I am near Kecskémet about 150 Km away (as the crow flies). Magyaroszág is what the natives call the country and they call themselves Magyars (pronounced Mod-jaws). Any Romanian will tell you this

The 750 Kg was a lifetime’s collection. Part of it came over in an ancient 3½ tonne Merc van. The rest of it with my furniture   One place I worked at I was sometimes asked, by security, to leave my car unlocked. Occasionally they found stuff that was ‘identify, mark and destroy’. But someone forgot to do it so it just had to vanish! All sorts of stuff, from a box of left-handed 9 BA screws to a billet of weird hand forged non magnetic ?steel?

Hansrudolf hello trumpets are usually varnished so Brasso will take a lot of elbow grease.  An on site test would be to take a mite of brass with you and see if you can scratch their sample. If the sample is harder than your bit of brass it may well be PB.

‘lace w:st=”on”>Hungary lace>’ seems to be something generated in the file transfer system which the website uses. It may be due to Windows Vista –Come back NT4 ALL is forgiven!

Keep you posted on progress, but I am still in the investigation stages.

[Keith Wardill 1Participant @keithwardill1]

HI, Richard,

 

The locals here have a similar identity problems – maybe 50% of our neighbours claim to be Magyars, when in fact they and their forebears have lived in Romania all their lives – the Magyars are a race, as opposed to a nationality – some here have never even been to Hungary, and we are only 40km from the border.

 

As I mentioned earlier, the shop has what they call brass on its shelves, but it is difficult to make any distinction between it  and the material they call PB. I have lots of brass (maybe 50kg of hard naval brass ingots), so perhaps they’ll let me compare them when I have time.

 

Hansrudolf – you are probably right about the trumpets in Romanian villages – we have a brass band which performs (?) at every funeral. Not sure I can get them to come into Arad to make a comparison . The size of the PB rod I have is just over 2cms dia, and was bought from a dealer at the Sinnsheim Echdampf Fest for almost nothing, along with some other odds and sods for stock. (It will get used one day).

 

I’ll make a check when I get chance, and see what is what.

 

Sorry you don’t get on with Vista Richard, but after working with computers for over 45 years (first one was an Elliot 803 serial machine in 1964 – size of a large room – 1 kword magnetic core memory), I would never go back to NT4 – horrible. Try Windows 7 – not perfect (its Microsoft), but it is a reasonable crack at Windows.

All the best.

[Richard ParsonsParticipant @richardparsons61721]

 

Snap! My first machine for which I had to help design a ‘bulk picking system’ in 1963 was an ICL1500. It was three machines in one large room, 1 working, 1 having its valves changed and 1 warming up for tomorrow. The warm end of the cooling system was excellent for warming up the meat pies for the night shift.  It had a 3Kword memory and a 3’ Bryant disk which had to be started by hand.  Later on I designed the prediction part of the stock control system for the 1900.  Then I went to worship at ‘Big Blue’ a 360/55 which had 64 Mb of ‘real’ and the idea of ‘virtual’ memory.  Was your Eliot a process control machine –Hot ends of Rolling machines etc?

By the way ‘Magnetic matrix memories’ are still being produced for the military.

I do not blame your Magyar speaking population is probably quite right not to cross the ‘Medicine line’. The locals have their problems. They will not listen to anyone (even their fellow language speakers on your side of the line). Over the time I have been here when we need casual labour we try to get Hungarian speaking Romanians. 

Actually I liked NT4 it was a release from MS DOS (actually I used Dosshell). But I think my favourite was IBM’s OS MVS. I am about to switch to Windows 7 less file bloat etc but I do not want to loose any more of my ‘legacy systems’ and I do not like Microsoft updated which remove old but very useful facilities and replace them with things are very dodgy.  I am having to re-write my gear wheel search facility nasty it was highly procedural in structure.

My late wife was always complaining about my metal stocks and wanted me to give them to her sister’s fancy man.

 

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