Member postings for Redsetter

Model engineering is in fact about getting your hands dirty and making physical models.

You will learn far more about the practicalities of valve gear by making a model than you will by playing on the computer. Certainly once you understand the basics the computer is a valuable design tool, but the OP has exactly the right idea.

I strongly object to being called "old hat". You just want to impress us all with your computer skills, don't you? Well, jolly good, I'm impressed.

You need to make the model reasonably large so that you can see what is happening, as very small dimensional changes can have large effects on the valve events. The only significant metal part in my father's model was the connecting rod, which was a 12 inch hacksaw blade. The design was scaled up to suit this from one of the full page drawings in Martin Evan's book, so the model fitted on a board 18 inches long, which was quite a practical size. I wish I still had it!

Excellent project! My father made me a model of Walschearts gear about 50 years ago, using mainly cardboard and drawing pins, and we both learnt a lot from it.

A set of drawings for a locomotive such as Martin Evans Simplex, Don Young's Black 5 or even LBSC's Tich will give you good dimensions for the components. You will need to model the valves and ports as well in order to see what is happening.

Greenly's "Walschearts Valve Gear" and Martin Evans "Model Locomotive Valve Gears" got most of it right and are well worth reading, though some of the finer points of design are glossed over.

There is a lot of variation in the design, and generally the gear has to be designed to suit a particular locomotive. Once you get started you will see why.

You will find it fascinating, but dangerously addictive.

I have in fact driven saturated and superheated locos in broadly similar conditions over many years and I am not convinced either way. As an engineer I think for myself and I take into account all aspects of the problem in hand.

Now the great god julian has spoken and all his sheep bow down to him, instead of having an intelligent discussion. We should be trying to help the OP with his questions. It's all about winning the argument, not solving the problem.

We are only playing with toy trains and anyone who is worried about about fuel and water savings in that situation needs to get a life and get out more. He may enjoy the meetings of the Flat Earth Society, if he isn't already a member.

It tends to be forgotten that superheaters only work when they are properly hot and this takes some running time to achieve. I have driven 5 inch gauge locos which are not superheated, and they work perfectly well. Possibly they use more coal and water than their superheated counterparts but this is very difficult to quantify, and so what, anyway? In average start-stop running on a club track I am not convinced that superheating makes much difference.

Dean,

It is not surprising that Zoe was unpopular. In 1957 there was very little interest in narrow gauge prototypes and Gauge One was also a minority interest, confined to scenic layouts for which Zoe would be quite unsuitable. There are many pitfalls in an eight coupled chassis. So having built a large and quite complicated loco you would have nowhere to run it.

With due respect, you would understand a lot more about LBSC and his locomotives if you built one for yourself. Many of us have done it, and found it quite difficult.

Thank you - I am familiar with the numbering you gave, hence the question, Having now had a good look at it, it is not an NVR switch as claimed but a plain push button on-off, which explains a lot.

I have just bought a new NVR switch.

It has 6 terminals. One row is numbered 11. 21, 31.

The other row is numbered 12, 22, 32.

I would like to know what these numbers mean so I can wire it correctly.

Just to save anybody asking, because somebody will - No it did not come with any instructions.

Thank you for your help.

I have only ever seen one of these in pieces and the valves and ports were quite nicely machined, so I would suspect that the problem is somewhere else. They can certainly be made to work well.

The design is said to have been based on Neville Evans' Didcot.

Modelworks instructions were quite well illustrated - there most be some around.

IIRC there was a known problem with the Modelworks valve gear - either the eccentrics were wrongly positioned on the crank axle, or the eccentric throw was incorrect - something of that sort.

There is a 14xx thread on ME Clearing House, maybe of some help.

Surely it would be worth trying to set the valves under air pressure first? It would save a lot of dismantling and is arguably the most accurate method.

Going back to the original question, which has been discussed many times.

The poster is a beginner. The M type is a fine machine but the newest is about 60 years old and many will be considerably older. Any lathe of that period may have had heavy use and will have signs of wear, even if it is an M type. Some of that wear may make it inaccurate and some will be difficult to rectify. This is not the best option for a beginner, unless he wants to specialise in restoring vintage lathes - in which case he will very quickly need another one to do the work.

An M type or similar may only cost a few hundred pounds but by the time you have sorted it out and replaced the missing bits, you could well be approaching the price of a new Warco, Chester or Arc of similar capacity. These may not be perfect but they will be accurate, unworn and will work straight out of the box.

Most modern radiator valves do not have an adjustable gland nut. When they start leaking you have to replace them.

It should be obvious to anybody with half a brain that the simplest, quickest and most cost-effective method of getting power to the shed is to lay a cable from the house - either temporary or permanent.

I think David knows that already.

With due respect to David, he was an electrical engineer and is now a teacher. I am surprised that he needs to ask the question.

The best solution is to have the workshop in the house. If that isn't an option, just get a long cable, and start making something. Presumably that is the object of the exercise.

Stephen,

It is normal practice to assume a 3 jaw will not run true, and to start oversize then turn down to diameter. If you have to get a piece to run true you use a 4 jaw independent chuck, or a collet. If you really must do it in a 3 jaw, you can shim one of the jaws. It is what I and many others have done for the past 50 years. Don't worry about it!

Fascinating details in the video, and it does establish the cylinder position. It all looks very lightly built. As there is no sign of a valve spindle, I think the steam chest has been removed and blanked off using the cover plate.

It is indeed surprising that they got away with just lowering the axle, if they did - I wonder how well it ran?

Col, Stephens Society states that Stephenson gear was used which is what you would expect, but in this case it is best not to jump to conclusions!

The photo at Kings Lynn when new shows reverse lever on the right of the footplate, and some detail below the frame. The bottom eccentric rods can just be seen under the frame. There are two levers projecting downwards. I think the longer one is a brake lever and the shorter one is the connection to the weighshaft.

I have read somewhere (Industrial railway society?) that the cranks and eccentrics were outboard of the firebox, rather than below it, which suggests widely spaced cylinder bores with the valves between them.

The weighshaft and link suspension is the main puzzle. I am tempted to start drawing!

Joe,

Do you have any detailed information on the rebuild?

Looking at Ian's frame drawing of the 2-2-2, which may well be correct, the cylinders are horizontal and close to the bottom edge of the frame. In the rebuild the crank axle would be about 9 inches lower, the axleboxes would be falling out of the horns, and to preserve the geometry of the motion the cylinders would have to be lowered or inclined. All this would involve significant alteration (or replacement) of the frames.

It was quite a major rebuild and I think this has to be understood before making a model in either form. A look under the actual loco would reveal a lot.