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Easy-Peasy Carriage Build


MikeOxon

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Easy-Peasy Carriage Build or ‘How to build a carriage with no drawing, no measuring, and little time’

 

One of the vehicles I wanted to add to my collection for use with my ‘Firefly’-class locomotive was the early type of 6-wheel ‘open’ 2nd-class carriage. There is a full-size replica at Didcot Railway Centre, as shown below:

 

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Didcot Railway Centre – Replica ‘Fire Fly’ and train

 

At first glance, those panelled sides might look to be a modeller’s nightmare but 3D-printing makes it extremely simple!

 

There are drawings of this carriage, by Eddy Lane in the appropriate Data Sheet from the Broad Gauge Society, so my first step was simply to import a copy of his drawing, as a ‘Canvas’, into ‘Fusion 360’. The drawing shows the overall length as 27’ 2½“ (i.e. 108.8 mm in 4 mm/ft scale).  Again, ‘Fusion 360’ makes it very easy to scale the ‘Canvas’ by means of a ‘Calibrate’ command, which simply requires the length of one reference line to be stated.

 

Now that I have learned about some of the tools that ‘Fusion 360’ has in its armoury, I have realised that there are many aids to creating arrays of similar features, such as the regular panels on this carriage. In fact, I only needed to create four types of rectangle: ( i ) the outline of the complete side, ( ii ) a ‘window’ opening with rounded corners, ( iii ) the upper side panel, and ( iv ) the lower side panel. I simply created one each of the required types, in registration with the ‘Canvas’ . After that, I could use the ‘Pattern’ tool to replicate as many identical rectangles as were needed to complete the entire carriage side! The same method can be used both for the ends and for the internal partitions.

 

Thus, a few simple steps were all that was necessary to turn a published drawing into a three dimensional model. The overall procedure is illustrated below:

 

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Stages in converting a published drawing into a 3D model, using 'Fusion 360'

 

I now had three ‘printable’ bodies that I transferred to my ‘Cura’ software, to produce a ‘sliced’ model suitable for my printer. Since these individual components only take a few minutes each, to print, I laid out all five partitions together as a batch, for which the total print time was only 45 minutes.  I also printed the sides and ends in pairs, with similarly short print times.

 

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Set of Printed Partitions created as a single job

 

To assemble the parts, I fixed the ends and all the partitions to one side, using super-glue, starting from one end and adding the partitions one at a time. I then weighted the assembly until the glue had cured.

 

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Steps in assembling the components parts of the model

 

After completing this side by adding the final end panel, I applied super-glue to the outer edges of all the partitions and the two ends. I then offered up the remaining side, pressing it into place until the glue ‘caught’. I laid the model on its side and weighted the upper surface until the glue had cured.

 

To show the end result of less than a day’s work, I added a chassis and a roof from one of the carriages I had already built:

 

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My ‘easy-peasy’ carriage

 

Of course, there are lots of finishing touches to add. The purpose of this short post was to show how a seemingly complicated design can be created quickly and easily, by making use of the tools available in 3D design software.

 

Mike

Edited by MikeOxon
Restore images

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Very neat job. The thing I really like is that you made it with separate sides, ends, and so on, like an old style kit, rather than trying to do it as a one piece item. When I say this to 3D people, they usually say “ah, but you’re not taking advantage of the facility 3D printing offers” whereas I’m convinced doing it the way you made this would give real advantages for things like quantity of material used, and finishing?

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Thank you, Northroader.  Since many railway vehicles are simple slab-sided structures, I find 3D-printing is an excellent way of providing surface detail that would be difficult to achieve by conventional means.

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9 hours ago, Northroader said:

Very neat job. The thing I really like is that you made it with separate sides, ends, and so on, like an old style kit, rather than trying to do it as a one piece item. When I say this to 3D people, they usually say “ah, but you’re not taking advantage of the facility 3D printing offers” whereas I’m convinced doing it the way you made this would give real advantages for things like quantity of material used, and finishing?

 

Hi there, there are definitely a number of trade-offs. Printing a model all in one go can be a bonus for some, as it saves time later. However, on the down-side, a lot of material can be wasted creating all the supports that are needed - especially in resin printers. In fact, you could use more material in the supports than in the actual model.

 

Getting the best finish out of the printer means getting to know it really well. Mike's prints are a world away from the ones he made just after buying his printer, mine are too. Finishing depends on a lot of factors that are determined when creating the file for the printer. These include layer height and print speed, but can also include material temperature (and temperature consistency), material quality, and even vibrations from not having a stable base for the printer. I've found a video recently of someone who even swears that the concrete paver under his printer makes a huge difference to print quality.

Definitely in this case, kit form is the way to go. Mike Trice also found creating a carriage in kit form with the sides printed separately was the way to go with Shapeways. I also think one of the possible dangers of 3D printing can be getting carried away and forgetting that the insides of some of these models need painting and such.


In other words - I generally agree :)

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Mikkel

Posted (edited)

The kit form also means you get to build something. I like that combination of new- and old school modelling. 

 

It looks very good Mike, and all that in a day! 

 

Edited by Mikkel
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2 hours ago, JCL said:

.................

Getting the best finish out of the printer means getting to know it really well.

..................

That's a very good point, Jason.  When I look back on all the troubles and frustrations I had when starting, it seems amazing that I now simply press the 'go' button and let the machine get on with it.  I'm sure that there are still 'tweaks' that I could make but, for the moment, I'm content.

 

I also spend some time planning how to orientate the model, so that supports are not needed.  For example, by laying the sides flat on the printer bed, I do not have to support the tops of the window openings.  I have another model under way, where I have deliberately split some components so that I have flat surfaces to lie on the printer bed.

 

At present, I get a different finish on top layers than below, which shows as a different surface texture within the panels, which I find quite attractive.

 

Mike

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Thank you, Mikkel.  Various (pleasant) things had distracted me from doing any modelling for a while, so I dashed this one off to keep my hand in :)

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Brilliant Mike, and so well executed.  I do like the fact that you make it out of parts; it does seem the best way to go.

 

I feel we should have a race as to who can produce a coach in the shortest time.  Let me see, my quickest build is two coaches in six months!  (We will ignore all the others that are not finished yet.)  :D

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Thank you Chris - but this one is not really finished either - buffers, door handles, benches inside, and so on...

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That looks excellent Mike. On a different note, were broad gauge buffers comparable in sizes to standard gauge ones or are they bigger?

 

 

Douglas

Edited by Florence Locomotive Works
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AFAIK, Douglas, BG buffers were of similar diameter to standard gauge, although of course, the spacing was different.  Early buffers were of leather, stuffed with india rubber and horsehair, with iron bands to keep them in shape..  Later GWR designs were standard for both types of stock.  Some shunting engines were fitted with planks to widen the area of the buffer head, so that they could work standard gauge as well as BG stock.

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I think BG buffer spacing was 5' 10", whereas standard gauge is 5' 8".  I realise that the need for extended-width buffers when shunting was mainly because of the offset between the centrelines of BG and standard wagons on mixed-gauge trackwork.

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I accidentally rated my own post 5* by carelessly moving the mouse around - any one know how to remove it?  Someone else had already given it a genuine 5* rating so it's not actually falsified the overall rating,

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