Originally printed in Gazette Vol 20 No. 12 as The Technical Committee 3D Printing Project. Part 1 of this article appeared in Gazette Volume 19, issue 8, August 2015.
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Finney7	Richard Lambert
	01299 271918
	Email: finney7richard@yahoo.co.uk
	Web: http://www.finney7.co.uk/

https://www.lgminiatures.co.uk

The T9 locos were the mainstay of London and South Western Railway express power in the late Victorian period. Designed by Dugald Drummond, they were built between 1899 and 1901 at the LSWR works at Nine Elms and by outside contractor Dubs & Co. Glasgow, which later became the North British Locomotive Company. Numbering 66 in total, the locos were later improved with superheated boilers and lasted well into Privatisation. The last survivor was withdrawn (and preserved) in 1963. The model build made use of the highly regarded Martin Finney T9 kit. Two examples were built - 113, the first Nine Elms loco, and 702, the first Dubs and Co example with a cross-tube firebox. The kit is well designed and builds into an accurate and well detailed model, if the usual care and attention is taken. Both models were paired with six-wheeled tenders, and finished in LSWR livery.

From the outset the project was used as a test-bed for 3D printing technology and its possible applications in O gauge. The GOG Technical Committee ex Chairman, Steph Dale, produced drawings of parts and a detailed design for the inside motion and valve gear. These were drawn in a suitable software package by (Technical Committee member) Simon Thompson, enabling plastic patterns to be 3D printed. The patterns were passed on to Laurie Griffin Miniatures who produced a kit of brass parts for modelling inside motion suitable for a number of Drummond locos, including the T9s. The design and drawing stage was described in the earlier Gazette article by Simon, and this second article describes how the castings were successfully used to produce working inside motion.

The tender builds deviated little from the kit instructions. Minor modifications were made to improve the appearance of the brake rigging and water valves. The etchings for the distinctive LSWR lamp brackets were replaced with cast items from the Laurie Griffin range. The electrical pick-ups (simple phosphor bronze wire wipers) were fitted to the tender inner chassis. Nickel-silver handrails were used to represent the polished steel ones used in that period.

The locomotive bodies were also built mainly as described in the instructions, however a lot of detail was added to the insides of the cabs. Pipework and fittings were copied from drawings and photographs kindly provided by Steph and Peter Smart. More prototypical reversing and sanding handles were added. Damper and cylinder draincock levers were fitted to the floor, and displacement lubricators were added to the cabsides. Square Perspex rod was used as the safety glass around the water level indicators and wood veneer was used to represent the cab floor planks. Crews were added for which a special mention is due to Mike Sheardown. He expertly painted the figures, and, as a passed fireman, suggested a few often-forgotten details that bring the locos to life, such as cracking open the firehole door and the ashpan dampers below the firebox.

The kit allows the portions of the chassis frames above the footplate, between the splashers and smokebox, to be spaced prototypically. However, as the kit is designed to finescale standards, the spacing of the chassis frames below the footplate are 3mm too narrow. I dislike the step inherent in this design, so decided to compromise by widening the frames below footplate to 29mm and narrowing the portion of the frames above to match. I made prototypical frame stretchers to widen the frames. This process also required the fabrication of new smokebox fronts and backs, although I was able to utilise the smokebox wrappers supplied in the kits. Alterations were also required to the footplates and the valve chest covers. Whilst fabricating the smokebox fronts, I took the opportunity to include an opening smokebox door and all the correct piping, blast pipe and petticoat pipe. A lovely tube plate etching was supplied by Eastside Pilot.

To avoid an unsightly horizontal join in the chassis frames at footplate level they were split vertically - the inner part of the upper frames are attached to the main body of the chassis, and the outer part of the upper frame is attached to the footplate. The join is now along the top of the frame and is barely perceptible. The T9 ashpan has quite a distinctive shape which is not fully represented in the kit, so a new pair were fabricated, including bases – this has the advantage of hiding the motor and gearbox and providing a vessel to fill with lead ballast.

The front bogies were mainly scratchbuilt using a few of the etchings provided in the kit. Side control and downward springing was incorporated to minimise movement. The front part of the chassis, behind the front bogie wheels, was narrowed very slightly to allow the models to negotiate 6ft radius curves.

It all had to be assembled with a lot of care as the clearances are very tight. The cylinder front and rear were adjusted to match the frame spacing and fitted in place using the GA drawing as a guide. The slide bars were soldered into the motion bracket and an etched brass jig (supplied with the castings) used to position the assembly accurately in the model frames. The rest of the rods and spindles were added using a drawing.

Number and works plates were sourced from Diane Carney, and the models were painted and lined by Warren Haywood. A blow-by-blow pictorial account of how the locos were constructed can be found on the Guild’s website under ‘Forum>My Workbench>On Nick Dunhill’s workbench.’ Thanks to Steph Dale, Simon Thompson, Peter Smart, Mike Sheardown, Diane Carney, Laurie Griffin, Warren Haywood, Stuart Tebbett and John Craig for their help and inspiration. Part 1 of this article appeared in Gazette Volume 19, issue 8, August 2015.