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* Pop Rivets and Underframes

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* Assembling a low cost CNC Router / Laser Etcher

* OpenSCAD and Sample 3D Print Files

* Extended Guide to 3D Printing


Loco Types and others.

Most G3 locos are just that -Locos... But there is a growing number of DMU and EMU type "sets". A Southern 2NOL is a nice size and there are several GWR "flying bananas" around. Something the size of a Brighton to Victoria dual 5BEL Pullman set would be a challenge -as it would be nearly 30 feet long... It is recommended that the leading and trailing cars of the set be powered, or to power a bogie per car of the complete set. Due to physics the mass of the car will cause it to prefer to continue in a straight line. To help counteract this mount the batteries in the middle of the car. In a set all the motors are going to have to feed from a common "Buss Bar" layout from the ESC. Thus you are going to have to make sure that the connections between each car are secure. You can make scale-like false connections between the ends of the cars, but underneath try using something like a Tamiya connector, MOLEX or similar to handle the load and power. Always place your connectors in places that are easy to disconnect.

Plans and suppliers for parts.

Most of the plans currently are from a few suppliers.

  • The National 2.5GA will supply plans to non members at cost, they have a 10% rebate for members and 5% rebate for members of the G3S.
  • Reeves 2000 may have some old 2.5" gauge LBSC plans, but they are moving out of this market.
  • GLR Kennions sell plans for LBSC's classic designs.
  • Locomotive Design Co sell a number of plans for various locos and rolling stock - including coaches, wagons, toads etc.

Laser Cut Parts.

The main problem with metal laser cut parts are that the edges can be razor sharp until cleaned with a stone or emery. There can sometimes be hardened spots left by the heating, causing drills and taps a few problems. These are more of a nuisance than a hindrance. Laser cut ply is a nice thing to handle but there are some problems with the layer of carbon on the edges, these will need to be roughed off otherwise the glues will not grip well. Most Laser Cutters use AutoCAD R 2000 DXF or DWG type files to work from. Some charge by the time taken, the part complexity, or the quantity of sheet material used, and some have a fixed minimum charge. Some materials cannot easily be laser cut, but most metals are catered for by someone, somewhere. If you are set on using brass, stainless or aluminium then persevere, but costs may be higher than for a basic steel cutting shop. You will normally have to supply your drawing at full model size in metric. Some CAD systems show circles on screen as polygons, but usually they will cut as true curves. Annotate your drawing with at least one dimension to enable the manufacturer to confirm the scaling and units used. Optionally you can mark the sizes of finished holes, noting that M4 is not the same size as 4 mm. If you mark a hole as M4 it may be assumed by the operator that you are going to tap it to that thread -thus the hole will be smaller. If in doubt on anything, have a conversation with your supplier.


Custom Laser cut parts. There is only really one dedicated model engineering supplier here and that is Model Engineers Laser (MEL). MEL have quite a stock list of parts for G3 or 2.5inch "off the shelf". For specials to your own CAD design they will willingly cut your pieces and then ship them to you with the invoice. Standard steel thicknesses for MEL are 0.9, 1.2, 1.5, and 2.0 mm. For brass they are the same as steel but with the addition of 0.5 and 0.7 mm. Most parts suppliers will have a range of laser cut parts for sale. Williams Models have a large range of wagon axle systems that are made by this process.

It's always worth ringing around your local town for a competitive quote on your drawn parts if you have a big order. One member has used Accrofabs in Derby to good effect.


MEL will do parts in wood. They seem to supply Peter Woods Models with their work.

Derbyshire Laser commonly cut ply thicknesses of 0.6, 0.8, 1.5, 2, 3 and 5 mm. They also have experience of ultra-thin down to 0.1 mm, and can go as thick as 12 mm with some cautions on edge quality. Partial depth cuts can also be made by reducing the power, so this should be good for door or window frame outlines. One member has adopted their 1.5 mm ply to produce carriage sides, using DWG or DXG files. They charge by the sheet used, a sheet will take six LMS carriage sides. Recognising that ply has a dominant grain direction, thin ply bends one way far better than in the other. Take cognisance of this on your CAD drawing if you want to bend your sides with a tumblehome, and make sure the supplier knows this.


Photo etching a plate is a complex and costly procedure. This is reflected in the price. I have never assembled an etched kit but they are popular. The principle is to solder the tabs together to produce the model. A temperature controlled soldering iron will be required as will precise melting point solder. A typical soldering iron will cost around £50 and be circa 50 Watts. Messrs C+L Finescale and DCC products sell a large range of solders and fluxes -but care must be taken with the fluxes -some of which are quite "nasty". Be sure to use a neutraliser and wash your joint afterwards. Commercial 60/40 tin lead solder can be used but it has a variable melting range and can cause problems when affixing new parts near existing ones..


These can be made from Brass, Whitemetal, Bronze, Iron or Resin. Castings are the parts you buy from the suppliers that enable you to complete or modify your model. Brass provides the most "refined" of the common castings, as the "lost wax" casting method allows it take fine detail. Most Iron and Bronze castings are found in the catalogues of steam locomotive parts suppliers as only these materials are fully steam proof. These will look quite crude as you are paying for the shape that you will produce via machining, the original ugly lump exterior will end up as turnings in the bin. Resin castings can be quite detailed but are brittle in thin sections. The common casting materials are semi opaque and only when they have been primed does the surface detail present itself. Epoxy and CA style glues are the most suitable for jointing these. White Metal castings may be classed as the "Ford Cortina" of castings. They have been around for well over a century and they still serve us well. Modern castings may use rubber moulds rather than machined oak but the principle is the same. They are of middling strength and can be used to make things like axle guards and brake stanchions. As such they have no structural strength and should be classed as ornamental, thus their use for "dress up" parts.

It is quite possible to make your own White Metal and Resin castings and this is covered under DIY Casting

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Page last modified on January 08, 2020, at 07:15 AM