Wednesday, December 30, 2020

How I assembled a 3D printed Southwold Railway LWB van


I acquired my first 3D printer in March (about the time Covid first struck) and since then have been busily printing out various objects which I downloaded from the internet. It didn't take long before I found the need to draw my own objects for printing. After some abortive attempts in trying to get to grips with SketchUp and FreeCAD, I found my way to the TinkerCAD website and since then have never looked back. 

I find TinkerCAD suits my way of thinking and I have found it to be a lot more intuitive than the other 3D drawing packages. It probably doesn't have as many tools and may lack the sophistication of some of its rivals, but I have found it does the job I want it to do and I now feel quite confident with drawing most things (see How I drew an open wagon with TinkerCAD).

My most recent drawings have been to produce the parts needed to construct a Southwold Railway long wheelbase open wagon. I have been steadily drawing the goods and passenger rolling stock which ran on the Southwold - this model is the seventh I have now produced.

Ultimately, my aim is to draw and construct all the railway's variations of stock. I'm currently working on a drawing of one of the Cleminson 6-wheel open wagons.

Once I had drawn all the parts in TinkerCAD, exported them as .STL files, sliced them in Cura and printed them out, I could start assembly.

I usually start by constructing the chassis.

One of the spacers was glued to one of the solebars. As you can see, I use the grid on a cutting mat to make sure everything is square. Note also, the lug on the spacer is facing outwards.

Because my layout represents a thee foot narrow narrow gauge railway, my track gauge is 45mm and hence the spacers are 60mm in length which is appropriate for the Bachmann/Lilliput 32mm diameter metal wheelsets I use. I have also produced 44mm long spacers if anyone wants run the model on 32mm track.

The second spacer was then glued inside the other end of the solebar.

The second solebar was then glued to the other ends of the two spacers

 Incidentally, I use thick superglue and an activator spray for assembling my models printed in PLA. If I printed them using ABS filament, I would use acetone.

The chassis was now more or less complete.

 Glue was smeared on to the rear of one of the end pieces, behind the headstock, and the activator spray was squirted on to one of the spacers on the chassis.

 The end was then joined to the headstock on the chassis and pressure applied for a few seconds.

This process was repeated for the other end piece.

One of the side pieces was now glued to the ends.

..... and the other side was similarly attached.

 At this point I inserted the wheels into their axle holes. Before the floor and centre spacer are attached, the solebars are quite flexible and easily allow the wheelsets to be inserted.
 The floor was now glued into place. I used 2mm plasticard, but a floor piece is included in the 'kit' if you prefer to have everything 3D printed.
 The brake shoe and hanger was then glued to the floor; positioned so the hanger was behind the pivot for the brake lever and the shoe was aligned with the relevant wheel.

Another spacer piece was now glued across the centre of the chassis.

A roof support was then glued across the centre of the wagon - on reflection I should probably have used two supports as the roof slats are quite flimsy.

The roof slats were then tidied-up .......

..... and one of the edge pieces (with the shorter lugs) was glued to one edge of the roof.

The other edge-slat was glued to the opposite side of the roof, followed by a normal slat.

The rest of the roof slats were now glued into place, alternating from one side to the other so that the final gap is roughly in the middle of the roof.

Like me, you might find that the final slat needs to be trimmed to fit into the remaining space. A sharp craft knife is sufficient to pare it down to size.

To finish off the roof, I use 0.5mm thick plasticard, cut to overlap the sides and ends of the roof.

I usually glue the roof covering in stages. I start with applying glue to about a third of the roof on one side and then glue one side of the covering to it, making sure it is square.

I then apply glue to the next third, and finally to the last third.

The wagon was then inverted and the excess roof covering trimmed off with a sharp knife blade.

Finally, I added my own design of centre buffers to match the height of those on my other wagons.

The wagon will eventually be given a couple of coats of Halford's grey primer and the solebars and metalwork picked out with black acrylic paint.
If you are interested in downloading and printing out my kit, then it is available on the Garden Railway Forum under 3D printing.


Thursday, December 24, 2020

How I constructed one of my 3D printed Southwold Railway wagons

Since acquiring a 3D printer (see How I assembled my Anet A8 clone printer) and the skills to draw my own models (see How I drew a Southwold Railway wagon with TinkerCAD), I have been steadily drawing and assembling Southwold Railway wagons and coaches. I have made the .STL files for these models available on the Garden Railway Forum website for anyone who might be interested.

For my own sake, I have tried to make the assembly of the parts for the wagons fairly straightforward, but have decided to show, step-by-step, how I go about their construction to avoid any confusion.

Once all the parts have been downloaded, sliced and printed out, they will need some cleaning-up and the holes in the axle boxes might need to be opened up with a 3mm drill bit.

 I then start with the chassis. 

Firstly, I glued one of the spacers to the end of one solebar, in line with the headstock. I use the grid on a cutting mat to make sure the parts are square.

Then, a second spacer was glued to the opposite end of the solebar.

The second solebar was then glued to the other ends of the spacers.

If you are using the 32mm spacers, at this point you need to glue the small conversion pieces behind the ends of the heastocks on the two wagon ends. 

One of the ends was then glued to the headstock on the chassis.

I then glued the other end to the other headstock on the chassis.

One of the sides was then glued between the ends, ....

...... followed by the other side.

NOTE: When using parts printed with PLA, I use thick superglue and an activator spray to speed up the setting time of the glue (a few seconds rather than a minute or more).

I then either measure the size of the floor and cut it from 2mm thick plasticard or print out the floor piece .......

..... and glue it into place.

Sometimes, I then glue another spacer across the middle or leave this until after I have fitted the wheelsets - it depends on how much the W-irons on the solebars flex.

The wheels are then fitted into their axle holes in the axle boxes.

The brake shoe and hanger was then glued to the floor so it was positioned just behind the pivot of the brake lever and in line with the adjacent wheel.

I then glued the buffers to the headstocks. I have a simple jig to ensure that they are mounted at the correct height to be in line with the buffers on the rest of my stock. You may have different mounting heights or wish to use chopper couplings.

Once the buffers were glued on the wagon was ready to roll.

Like me, you may need to add your own couplings. I have my own, what I like to think are less obtrusive version of LGB hook and loop couplings and so mount these on blocks glued beneath the wagon floor.

I am slowly drawing and printing all the styles of wagon and coaches which were found on the Southwold - including the 6-wheel coal wagons and coaches. I will eventually make these available on the Garden Railway Forum website (once I have perfected the 6-wheel pivoting chassis to my satisfaction).