More rubbish from TAFF
In July, we received the first shots of the Dennis Eagle, the second dustcart in the Oxford range, our design techniques have changed over the years and I thought back to the last dustcart that we started developing nearly 15 years ago.
76SD Shelvoke & Drewry Dustcart.
A big lesson we have learned over the years is that the easy part is deciding the subject matter, designing it is the bigger challenge, particularly if you cannot find a vehicle to measure up. In this case, we searched high and low to find a W Type dustcart manufactured by Shelvoke & Drewry, a vehicle that had been introduced in the late 1940s and had back then been purchased by many councils around the country. The history of the company dates back to the 1920s when it was founded by Harry Shelvoke and James Drewry, who had previously worked together at Lacre, a company best remembered for producing road sweepers.
The company's first product was the Freighter, a small-wheeled low-load height two-tonner. This was initially marketed as a general purpose lorry, but it soon found its niche.
In the 1930s Shelvoke & Drewry began to develop more specialised vehicles for the municipal market, including gully emptiers, cesspool cleaning vehicles, and street watering and washing vehicles. The company also began to manufacture fire engines, buses, and forklift trucks. During World War II, they produced a variety of military vehicles, including cable drum carriers, ground equipment for the Royal Air Force, and ambulance bodies.
After the war they continued to be a leading manufacturer of municipal vehicles. The company's waste collection vehicles were particularly innovative, and they were widely used by local authorities throughout the UK. Sadly the company went out of business in 1993, but its vehicles are still fondly remembered by many.
After months of hunting we drew a blank in finding a vehicle to measure up. We began to wonder if we should change to something else, then we were made aware of a rear body in a scrapyard
So our plan was
- To measure up the cab on a 'gully emptier/cesspool' vehicle
- Base the rear on the scrapyard find
Scanning was not an option back then, it was a measuring job from which we would create a handmade model, before refining into parts for toolmaking. Then we realised that the cab we had found to measure was a shorter version, but the front would be good enough, as we had also come across some drawings which we could cautiously cross reference. Experience had shown us that drawings from the 1950s often differed from the real thing.
Short Cab gully emptier/cesspool vehicle
The rear body in all its glory ! You can't win them all.
So putting together all of the above, plus some details which we extracted from the drawings enabled us to come up the following measurements.
1. The Length
The traditional way of measuring, taking a datum line and then measuring each way. It used to be painstaking and the more curvatures that you found on a vehicle the harder it became. It took around two days to measure up:
- The narrower cab was adjusted to the longer variant.
- The scrapyard rear was dug out around the edges to get as close as we could to the real size.
2. The Widths
3. The Heights
Getting to this stage had already taken us around six months, far longer than anticipated and now we needed to build a prototype to check the functionality and ensure that we could capture the look of the vehicle.
This was the first off resin sample which we made in the UK.
After some refinements and functionality changes we moved on to some production patterns. It was not typical to go through the duplication of sample making like this, but back then it was more difficult to communicate with the toolmakers.
The final sample prior to creating the CAD, with a change to a screw instead of a pin, which then we later reversed.....
Then the CAD was completed
After approval we began cutting steel to create the moulds and ten weeks later the first shots became available.
Then we went through refinements and around 15 months later the fisrt products arrived in the UK. Certainly not the easiest of processes.
We have released five liveries:
You have to laugh, after all we had gone through a few years later we had a call from Peter Johnston in Northern Irelandnwho was planning to restore a W Type, having seen our vehicle he asked if we could supply any information on the measurements/design etc, we happily obliged and in 2013 his restoration was complete.
If we had only waited a few years perhaps our life could have been easier !
Then jump forward to 2022.
76DE Dennis Eagle Olympus Refuse Truck.
This was a totally different prospect as a modern vehicles are usually much easier to locate and the Dennis Eagle is seen on roads across the UK. We didn't have the benefit of CAD, so we could digitally scan a vehicle and build up the design from there.
- Create the components with CAD
- Cut the steel.
Locating a vehicle was relatively easy.
Note the laser scanning spheres. These capture everything in their 'field of vision', so placing at controlled points around the vehicle and at heights to capture roof detail is important to capture all of the imagery. The shape is no longer an issue as the scanning creates a point cloud that is extremely accurate. Every bit of detail is captured, and the individual scans are meshed together to create one scan of the subject - if you leave your coffee cup on the dashboard it will pick it up. Clear areas like windows should be 'clouded' with wax to capture the surface, duller surfaces are better than glossy more reflective surfaces.
The above are screen grabs of the Dennis Eagle scan, the widows being clear means the scanner looks through these and captures the interior of the cab showing the seats. The point clouds are literally what they say, not a surface, so we triangulate across the point cloud to create the surface. The greater the level of detail (more required dependent on scale) the more time this will take. In the early days this was a very manual process, but in recent times there is more automation.
The final CAD is shown on the above clip.
Then all we have to do is sit back and await the first shots.
Our Design Cells are already prepared and ready, so we are anxiously awaiting the first decorated sample.
To be updated on release follow this link to the Oxford Diecast website Dennis Eagle - enter your email address in Notify Me
So quite a difference between designing the Shelvoke and the Dennis.
I do wonder what it will be like in another 15 years.
As always, I do read your comments, but I am unable to comment.
So until next time.