Creative Heritage: 3D printing and model making

In what we hope will be an ongoing series of guest blogs on the site, we’re delighted to share this Creative Heritage piece, sharing the story of one of many creative ways of engaging with heritage and history, inspired by or aligned with the stories of Hemingfield Colliery.

This one brings together old and new technology as Peter Duthie shares his insights into planning, designing and fabricating 3D models of industrial electric locomotives. Peter writes:

The Spark

After retiring early from a career which started in optical communication technology but then took some unexpected turns, I rekindled an early interest in industrial history, railways and model making.

Having cut my teeth on a variety of projects, modelling a wide range of rolling stock, structures and buildings, mostly narrow gauge, I came up with the idea of modelling all electric narrow gauge systems which have worked in Britain, but excluding purely passenger tramway (though the boundary can be difficult to define).

An interest in early narrow gauge electric locomotives took me to the Friends of Hemingfield website and specifically to the Walker-Immisch cable-climbing locomotive mentioned on the Wharncliffe Silkstone Colliery page.

Engraving illustrating electric locomotive on fixed rope system used at Wharncliffe Silkstone 1890-1893?, Taken from advertisement for the G.E.P&T Co., May 1892

A web query produced an interesting and useful response from the Friends, who have asked me to share a few words on the reason for my interest.

Methods of making

Technology has moved on since I last cut and joined styrene and painted the results in the 1970s, and I was now able to use 3D CAD (Computer Aided Design) skills used professionally in industry to design and print 3D models, so-called ‘additive manufacture’, a term which contrasts with older methods of carving, shaping, milling, machining, etc, where material is removed to create the product.

Tools for the job

The design and modelling software I used in industry was capable and costly, but free versions now available for hobby use seem to be fine for model making.

3D CAD design for an engine house model (Photo credit: Peter Duthie Flickr Stream)

I use Autodesk‘s 123D Design on a standard laptop, with a mid-range Monoprice Select Mini printer, costing about £150.

Icing the cake

The PLA plastic filament process is akin to cake icing, with melted filament extruded under computer control to form shapes initially in two dimensions, then building into the third dimension by layering shapes.

3D printed model making: example of the tools and materials used – the PLA filament spool and 3D printer to the rear and right, together with the products: separate pieces reproduced multiple times from the same design, add in painted elements and fit together to create the final modelled objects. (Photo credit: Peter Duthie, Flickr stream)

Compared to alternative techologies used by printing bureaux such as Shapeways (where I started my 3D printing adventure before I invested in my own machine) filament printing does tend to produce a ‘layered’ finish, though this can be improved by surface finishing.

Technical challenges

The geometry of complex engineering designs can pose a challenge to the printing process for overhangs, and it is often better to split shapes into smaller parts for printing.

3D Printing, or additive manufacturing, building up a model at a line of melted PLA filament a time to reproduce the design file. (Photo credit: Peter Duthie Flickr stream)

Wall thicknesses cannot be as fine as e.g. brass metal, and compared to hand made models 3D printing will always be an approximation. Indeed mixing materials can often be a good compromise.

However, 3D printing does provide a way to produce simplified models quickly, and to replicate items such as colliery tubs where a large number are needed.

Most of my models are static, using wheelsets in 6.5mm, 9mm and 16.5mm gauges, but some have been motorised using commercially produced mechanisms. Where more obscure gauges are required or inside frames are involved, then even the wheels are sometimes printed.

Motorising 3D printed model elements (Photo credit: Peter Duthie Flickr stream

Scoping a project

To keep a potentially large project within bounds, I generally excluded battery locomotives, and started with overhead wire pickup, though that has since extended to include two rail and three rail pickup and return.

Having produced simple representations of many of the more obvious prototypes, I have been chasing down information on increasingly obscure and elusive early machine, hence my interest in the Walker locomotive used underground at Wharncliffe Silkstone colliery.

The Industrial Railway Society‘s handbooks, together with the IRS’s web forum, are a helpful way to identify NG (Narrow Gauge) electric railways, though some remain difficult to find plans or photographs for, such as a reported one-time system in the plutonium factory at Sellafield…

Final product

The finished Immisch-Walker electric locomotive model, painted with accompanying coal tubs or ‘corves’ (Photo credit: Peter Duthie Flickr stream)

Creative communities: making and sharing

I have been sharing my project with a community of narrow gauge modellers through an internet forum, most of whom are more interested in steam and internal combustion traction, but the encouraging feedback on my maverick interest has helped me to keep going with this strange project.

Photographs of my models (and other material besides) can be found on my Flickr photostream at www.flickr.com/photos/139973551@N08/

At the last count, I was approaching forty different UK electric narrow gauge systems modelled, many of them associated with mining and tunnelling, but every time I think that I am nearing the end, I seem to discover more possibilities.

Keeping creative in challenging times

The COVID lockdowns have provided more time for model design and making, which in turn have helped reduce my frustration with other activities being curtailed.

The Friends of Hemingfield Colliery have been kind enough to share some further suggestions from early electrical engineering journals, so I should keep going for a little while yet.

Websites such as the Friends of Hemingfield are invaluable when it comes to researching early industrial technology, so keep up the good work.

If there are any questions, then I would be please to try to answer them – FoHC have my contact details.

Peter Duthie

December 2020.

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