Wednesday 30 October 2019

7/4" Gauge Bagnall Contractors Locomotive

By the way of a change of pace, allow me to introduce another of my longer-term projects.
A  7 1/4" gauge Bagnall Saddle Tank locomotive.

Time away from teaching over the half-term break has allowed me to get in the workshop push this little project along a bit which feels good.



I am building this model more-or-less to a published design, known as Sweet William.  However I will be changing certain aspects of the model to speed-up the manufacturing process and hopefully create a more robust and easier to maintain and run model.  The tender which I have designed is totally out of scale but should provide a stable riding truck for the driver which should at least be in the spirit of the engine, and which I hope will look smart.




I've built the whole thing up in CAD, and I think it will be quite an attractive engine when finished.   The tender design incorporates a woefully out-of-scale coal rail, however I've added this to make the engine easier to push about when not in steam and provide something robust which I hope will not bend or break if manhandled.  My intention with this locomotive is that it should be a hard-working miniature machine rather than a exact scale model, and I think that details like this will improve it's longevity and hopefully prevent the paintwork becoming too knocked-about when subjected to out-of-scale abuse.


To speed up the build process, I've made extensive use of laser-cut pieces.   The image below shows the parts for the tender as I received them from the laser cutters.  



The parts simply slotted together and took less that 20 minutes to weld-up into a really strong construction.




The main frames are being assembled here and are of a mostly welded construction.


After a clean-up, time for a lick of paint.


The axleboxes on the published design have been replaced with self-aligning take-up bearings, more commonly used in conveyor belt mechanisms.  These should last a lifetime.


One of the tasks this week has been the pattern making for the cast iron cylinders.  Here, I'm testing the fit of the pattern whilst refining its design.  


The cab gets a quick coat of primer..


The drivers controls have started to go in.  That on the left is the reverser, and the screw handle on the right will apply the brakes.




And there she (it?) is.  I've enjoyed taking a break from the 1:56 models over the past week or so whilst on half-term, and getting stuck into working with some materials and processes where my experience and confidence is a little higher.

Just in case anyone is wondering whether I'd thought to make a miniature version of this already miniature locomotive, the answer is...Yes!  I have the parts drawn-up as a little laser kit, together with some rolling stock and I'll probably build one up once the Vickers Vernon is complete - although I do now have quite a backlog.  🙂


Until next time,  thanks for stopping by.

James

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