Monday, September 07, 2020

How I constructed a luggage van by 3D printing

Until now, my 3D printing projects have focused on downloading and printing-out various items created by other people (eg seeHow I constructed a 3D printed beam engine and  How I constructed a 3D printed diesel loco - pending) or drawing simple objects for printing such as the seats for my CVR railcar or the window frames and ridge tiles for the Boneworks building.

After struggling unsuccessfully to produce viable 3D drawings with Sketchup, I came across TinkerCAD which seems better suited to the way I think and learn - see How to draw a window frames with TinkerCAD. Having mastered fairly simple drawings, I decided to try using TinkerCAD for something a bit more challenging - a complete wagon.

 The first task was to research the type of wagon I wanted to produce. Having recently finished constructing a model of the CVR railcar, I felt it needed a small luggage van to tow. I tracked down a couple of photos of a County Donegal luggage van .......

..... and sketched out some rough dimensions for it, using the Hartland Loco Works (HLW) mini-series wagon chassis as the starting-point.

A large proportion of the wagons on my railway have made use of HLW chassis. They were once cheap (around £10GBP) and plentiful. Unfortunately, HLW have recently ceased trading and so, apart from residual stocks in a few shops and secondhand models the supplies will dry up completely - unless someone produces a 3D printable alternative (see below).

Once I had a rough sketch, I started by creating the side of the van in TinkerCAD.


The side is simply a series of rectangular blocks of various sizes linked together. The tools in TinkerCAD are cleverly designed to make repetitive tasks easier and so planks, for example, can be repeatedly copied, pasted and moved a set distance through the use of the 'Duplicate' tool. (See How I drew a window frame with TinkerCAD )

Once I was happy with the side, I then drew the end.


The trickiest part was drawing the curved section. After a couple of abortive attempts, I remembered that I had used a large dinner plate as a template when creating similar curves on models and so drew a large disk and sliced it off to produce the arc for the roofline.

These two parts were then exported as .STL drawings, imported into my slicing software (Cura) and printed each out twice.

The sides are designed to slot into the recesses in the ends and so, after a little bit of tidying with a file, the van was put together as a dry run. Comparing it with the photo, I realised I needed to make some adjustments to the parts and add some detailing.

The detailing on the sides was added first. Various strips of 1mm thick plasticard were cut, shaped and applied to represent the strapping and hinges. A length of 1mm brass rod was fixed in place to act as the door catch and four pieces of half-round brass were cut and attached to represent the hinges.

The process was repeated for the other side.

The sides were then glued to the ends.



My initial thought was to make the roof from single curved piece of plasticard, but in the end I decided to form it from plasticard planks. To support these, two roof supports were drawn and printed. The drawing for these was simply achieved by slicing off the top of the drawing of the end.

 10mm wide strips of 1.5mm plasticard were then cut and glued to the roof, starting at the outer edges and moving in towards the middle, so the final strip could be cut to fit (it was 4mm wide).

A piece of 0.5mm plasticard was then cut to size and carefully glued over the planks, starting on one side and applying liquid solvent in strips until the whole roof covering had been applied.

The body was then loosely fitted on to a HLW chassis and checked to make sure it looked OK and rand smoothly.

It was then given a couple of coats of Halfords' grey primer ........

.... before 1mm half-round nail art gems were applied to represented rivet and bolt heads.

I use thick superglue applied with the end of a cocktail stick to fix the gems in place. I find that there is usually sufficient residue on the end of the stick after using it to apply the dots of glue to pick up a dot and transfer it to the model.

The strapping, hinges and catches were then picked out in black acrylic paint and the roof given a coat of dark grey acrylic. The padlock (a small piece of plasticard with a 1mm brass rod hook) was painted gold.

As can be seen, the van looks OK behind the railcar. It's maybe a bit on the small side, but that's because I had no dimensions to go on and so based them on the size of the chassis - adjusting the dimensions so it looked in proportion.

There were various types of luggage van used on the County Donegal and some of them were about this size - though of a different design.

As you can see, I have added my own style of LGB hook and loop couplings, Bachmann 24mm metal wheels and Binnie Medium Carmarthen buffers,


POSTSCRIPT

I decided to develop my drawing skills further and add the details on to the 3D drawing in TinkerCAD.

I have now printed these new sides and ends out.

 The detailing seems to have come out well, ......

.... so I am encouraged to keep developing my skills in TinkerCAD.

 

I also decided to draw and print-out interlocking planks for the roof;

 ..... so it would make a more or less complete model.

At the same time, as HLW chassis are now no longer in production, I drew and printed out my own version - using the same dimensions .....

.... but with my own design of solebars, as I was never entirely happy with the look of the HLW solebar. I think my version looks more UK-based. It should be, I used photos and drawings of the Southwold Railway wagons as my guide!

The chassis glues together quite simply .....

... and can be used with Bachmann 32mm or 24mm wheels as with the original HLW chassis.


I have made the .STL files for the van and the chassis available on Thingiverse should anyone want to have a go at printing them out for themselves.

 

Post-Postscript

 I have now modified the chassis sides to include a simplistic representation of brake gear.

For me, TinkerCAD uses a far more logical approach to the production of 3D drawings. Drawings are produced by manipulating and joining three dimensional objects on the screen, whereas in programs such as in Sketchup, shapes are produced initially in two dimensions and then extruded into the third dimension. I suppose they are designed primarily for those who are used to using 2D CAD packages. 

I shall carry on tinkering with TinkerCAD. I find the logistics and skills needed to produce a decent 3D drawing every bit as rewarding and stimulating as making a model from scratch. And there is something very satisfying in watching the printer churning out something I have drawn.



3 comments:

Unknown said...

Great job, mate! I'm doing a similar thing in On18 scale! Living far from any hobby shops, my 3d printer has been a game changer! Now if only the grandkids will stop wanting fairies and Pokemon!
Dave

GE Rik said...

Hi Dave
Fortunately, or should that be unfortunately, I don't have any grandkids to make those sort of demands ...... yet ...... 🤔

GE Rik said...

Just realised that 0n18 is 18" gauge, 0 scale on 9mm track. That must be fun! I'm a great fan of Heywood's minimum gauge railways (eg Eaton Hall Railway near Chester)