That's Better

The J Class War Department general service lorry recreated by 3D printing it as a kit of parts. A far more accurate representation than that shown made with FIMO clay in the previous posting.

And in situ outside the Thornycroft Museum alongside Van No.1

For an in depth study of how the J Class was made please visit my other Blog.

David

Oh Dear

I mentioned in the previous posting that 3D print is more accurate than modelling in FIMO clay. I knew already that our Thornycroft J Class general purpose War Department lorry made in FIMO clay was too tall but I did not appreciate how out of scale it really was until putting both models side by side.

Clay on left, 3D print on right.

The clay model starts to go wrong above the chassis line. This will not do so, I'll need to remake it in 3D print for our Thornycroft Sidings layout and maybe a total of  five to replace the batch displayed on our Cliddesden Station layout.

I keep mentioning 3D print in these postings (I have made quite a number of different models using it during this project) but not gone into detail about the process. Well, I'm now going to take you through the entire process, warts and all. But, not here. The series will be shown on our sister Blog - amodelrailway.blogspot.co.uk. You may wish to follow there and set up email alerts for new postings.  But don't give up on this Blog, there is much more to come here.

To begin with read about the 3D printer we are using.

David

Thornycroft J Class Anti-Aircraft Lorry

History

Thornycroft manufactured 183 of this J class variant between 1915 and 1916. Each carried a 13 pound anti-aircraft gun. This one (below) had an interesting history, which you can read at The Great War forum here.



Briefly, it was acquired by Thornycroft in the 1920s for their own factory museum but during WW2 it was placed on the road embankment between the factory Chassis Store and Deep Lane to ward off German fighter planes! There it languished, rotting away until given away for free to an enthusiast in the 1960s. You can see the state it was in at this time on The Great War forum here.

This movie shows the gun in action. It actually shows two different gun emplacements. Look for the one mounted on the lorry, which is the Thornycroft. Note the number of Tommys operating it and their deployment of the lorry stabilisers.



A super detailed 1:32 kit is available from Tommys War.

Our 1:148 N Gauge Model 

Regular Blog followers will know that we previously made a J class general purpose War Department lorry out of FIMO clay. 

Now we have a 3D printer the J Class Anti-Aircraft Lorry was designed in 3D CAD and 3D printed in plastic as a kit of parts. This facilitates a much greater level of accuracy and detail than using clay. The model is our most detailed  to date, much of which is not seen in the photo. Did you notice that I fitted the gun barrel upside down? It has since been corrected. I'm not showing a larger photo because there are blemishes in the parts, due to the technology of this process, that are barely noticeable at normal viewing distances in this scale.

The trouble with 3D printing is that the plastic is extruded like string and laid down in rows, which are visible. It can also get a bit blobby for very small parts. In fact the wheels did print as blobs. The machine could not cope with the 8 x half millimetre round vents in the wheels! Much filing and drilling was required to get some resemblance of the cast wheels with solid tyres.

Below is the lorry alongside the chassis store in 1939.

david

Thornycroft J Class Lorry - Part 5

About 5,000 J Class lorries were built during WW1 by Thornycroft of Basingstoke (just up the line from Cliddesden). The majority configured for military use.

Here is a small batch sent down the Basingstoke & Alton line to Southampton docks via Alton and Winchester. Not a typical route for them I'm sure but my excuse is a blockage on the Basingstoke to Southampton main line!

I  first had the vision of creating this train many months ago. Anyone who has followed my postings on the J class or Lowmac will know they were scratch built.

Just to show not everything goes to plan in the world of railway modelling this load of five trucks will never run because our little Dapol M7 suffers too much wheel slip under load. A fact I did not know until I built them. The best it will do is three. Even with empty Lowmacs it struggles with five. They weigh no more than r-t-r trucks and the wheels spin freely. A lorry is only a few grammes too.

I have read the M7 might not have enough weight over the driving wheels to maintain traction. I might experiment in that area.

The J class story.

The Lowmac story.

David

Thornycroft J Class Lorry - Part 4

Five lorries now complete and out on manoeuvres at Cliddesden

On Station Road viewed from the South East

Station Road from the South West

Over Cliddesden level crossing.

Past the terrace houses

Now I need five LOWMAC waggons to convey them to France. 'N' gauge society have a nice GWR version but it's only available to members. So, I would have to pay to join and then pay again for the kits! I believe there is a brass etched kit available from the 2mm scale society too and GEM fleetline do a cast whitemetal kit for general sale at £9.50 each. I could also scratchbuld one or adapt parts suggested in this article.

I have not decided yet.

To Part 1.

David

Thornycroft J Class Lorry - Part 3

It worked! What was a ball of brown FIMO clay is now an 'n' gauge J class in WW1 livery.

You can see why FIMO was used, it lends itself to modelling curvature. I am particularly pleased with the canvas cover. It has a very fine mesh texture like canvas, formed by pressing a close plastic mesh into the soft clay to leave the marks. It also has that flexible feel of cloth as it wraps over the inner framework.

There is room for improvement in the assembly method that will be applied as I set about making a batch of these lorries (5 altogether). I have started with the wheels, shown in progress below alongside the improvised cutters.

Here is a photo of the lorry at Cliddesden on a trial drive shortly after its manufacture at the Tornycroft factory a few miles up the line..

To Part 5.

To Part 1.

David

Thornycroft J Class Lorry - Part 2

Progress is being made. The pre-hardened clay components are quite flimsy and easily distorted with handling so I have to make and bake sub assemblies, which are then glued together with Superglue. It is taking longer than I had hoped.

In this picture the chassis frame and its under parts is one sub assembly. The engine compartment another and the flatbed a third. Oh, and the wheels are separate sub assemblies, as shown in Part 1.

What you see here is about 1.5cm tall and 4.5cm long.

To Part 3.

To Part 1.

David

Thornycroft J Class Lorry - Part 1

I mentioned elsewhere about a desire to create a train of Thornycroft J Class lorries in wartime livery  (photo below).

To my knowledge this vehicle is not available from the trade in 2mm scale. The closest kit is the Gem Fleetline Daimler flatbed lorry from 1911. I dare say this could be bashed to get a bit closer to the J style. If  I only wanted one that would be my choice but at £6 a hit a train of them becomes expensive.

I have some success in modelling in FIMO clay, not vehicles but people. So, this is the medium I'll try. At this stage I have no idea if it is achievable. This may be the first or last posting on this subject.

The above photo was taken at Milestones museum of Basingstoke, which has a display of Thornycroft vehicles and more importantly a workshop manual that shows a dimensioned drawing of the J class chassis assembly.

Firstly, I modelled the distinctive wheels, which have some challenging profiles to create in parts that are only 6-7mm diameter!

Here are the finished items for one side of the vehicle awaiting firing in the domestic cooker. (FIMO clay is a man made material that is manipulated like plasticine and then made hard by heating in an oven). On the left is the smaller front wheel and on the right dual rear wheels. The dress making pins serve as wheel hub and axle. Whilst I was able to mimic the bulge and vent holes on the larger rear wheel for the front wheel it proved a step too far.

Believe it or not the rear wheel is made from 5 parts and 3 for the front. Below is a photo of items from around the home that were brought into service as tools to make the parts. I'll not go into detail on how and what parts they made, unless you want to know. I just thought it would be of interest to see the extent of objects used to make what might be considered a simple component.

To Part 2.


David

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