A Crompton class 33 story

[Frits]

Hello,

In the coming weeks, months I will start building my Crompton "diesel".

For a picture of the real Crompton go to http://www.class33crompton.co.uk , there are lots of them.
My progress up till now is that I finished the drawings of the bogie in my 3D CAD program TurboCad 8.1 Pro.
By the way, I did never see the real loco , but do my drawingwork from fotographs which I found in 2 books I purchased last year.

To introduce my filosofie of building such a locomotive, I will give you some of my views.

1. The locomotive should be constructed as light as possible, because I don't want to carry a heavy machine in and out of my car.
Oh yes, I hear you warning that it cannot haul a heavy train.
But as in the real train I will sit on my loco and not in the wagon behind it. Therefore my own weight can be calculated up to the loc weight and now I have enough adhesionpower the act as a strong freighttrain.

2. Most of it parts are made of aluminium. Of course because of the weight, but mainly while aluminium is easy to work on. And... it doesn't rust like steel.

3. My goal is to build a nice locomotive which looks as much as possible like its big original. But it must work like a good 5 inch locomotive and it should be constructed in a simple way out of easy to obtain materials with a minimum of skills to finish it in a reasonal time limit.
Therefore its all the time: Give a little and take a little.
But isn't that the fun of our hobby?

Hereby a picture of my bogie design.



Next week I hope to show you more.

Frits

[Alan Wood]

frits your drawing is very nice, but the real locos had hollow side sections on the bogies ,i have a possible source of some works type drawings and il see if i can get some for you. as i worked on these locos for the first 9 years of my railway career i have something of a special place for these locos.

[Frits]

Hi Alan,

My bogie has also "hollow" sides, although its probably a little bit different from what you're use to.
Maybe the pictures below will show better what I intend to build. Oh, and I'm sorry but, as being Dutch, I am used to metric measures, but if neccessary I can calculate them to imperial one's.

What you see is a 1/4 of the bogie and as you will notice the frame is made of 8 x 8 mm aluminium beams, which will be covered with 1 mm alu sheet. In the top picture the front sheet, brake-cylinder, stairs and sandbox are removed.



A view from the inside.



The frontbeam is a little revolving connected to the sideframes, because on the big bolt in its middle the whole motor and gear gondola will be also fixed revolving.
Because of this its possible to lift one wheel independend from the other and the spring you see will carry the bogie on the motorgondola. The whole springsystem will be clear if I show the rest of the bogie later on.

Never the less I'm always gratefull for any "inside" information I can get.
If you will help me and critisize my work, don't hesitate, I'll be glad to hear something from your expirience with this Crompton.

Frits

P.S. What you see is just a drawing, the real job starts tomorrow.

[Brent Hudson]

Hi Frits
What great pictures or cad drawings what CAD package do you use? When I tried to use CAD I found that I could make the parts in the time it took to draw it. I understand practice makes perfect but I only have a short life so must cut metal. One problem you will have with your design is with the springing. You need to have primary and secondary springing as the differance between loaded and unloaded will be so huge. I had problems with a rake of coaches with B4 bogies that rode badly when unloaded as their weight was not sufficient to track properly.
Brent

[Frits]

Hello Brent,

You're absolutely right about the time consuming drawing.
But as I said before, while I'm drawing, I design and consider several decisions.
1. Do I have or can I get the material I will use?
2. Do I have the tools and skill to make it?
3. Because I can render a nearly fotografic 3D picture in every possible view, does my object forfil my expectation?

Above all, I like to draw with my CAD program, I use TurboCad 8.1 Pro, which I own now since 2003. And yes, it is a rather complicate program. I'm still learning new aspects every day.
Today I found my first mistake in my drawing, which I introduced myself, not the program.
Lucky for me I had to shorten the particular part 2 mm.

About the springing, I'm not concerned because the loc will be driven only when the driver is sitting on it. If neccesary, I could put some rubber or secundairy springs inside the springs in order to spring with a light load.(one of my grandchildren for instance)
Lets take care first that it will ride at all.

The work is going on.

Frits

[Frits]

Hello,

A hint for in your workshop.

If you have to drill several holes with a variety of diameters,

drill the smallest diameter first!!!

If you drill a hole in the wrong spot you can always drill it wider.

Frits, who is still drilling and t... (what you call cutting thread in a hole? taping?