Sunday, January 27, 2013

Andy May's Models

 Some pictures of Andy's models can be found at the below address.

Great stuff especially as Andy now resides in England.

Tuesday, January 22, 2013

Make A Jig

A "Jig" is a type of custom-made tool used to control the location and/or motion of another tool or item.  A jig's primary purpose is to provide repeatability, accuracy, and interchangeability in the manufacturing of products.
In modeling we often spend much time trying to achieve consistency when we build multiples of items . This can be done by using a Jig which is made to suit the application, in our case, it may be bending wire for handrails or assembling bogies or to assist with difficult fitting of parts, a jig will often provide the answer to a multitude of problems.
Most modelers have at some time found a need to make a jig to achieve a result with their projects and so there must be a whole heap of ideas amongst our group which can be shared to hopefully assist newcomers and even old hands.
I would like to encourage  all contributors on our Blog to share their "Jig" ideas under this theme of
"Make a Jig"  
To kick off, here is a simple little Jig I use for applying the End Bargeboard to Double Skinned Roof carriages.

This little jig is made simply from some styrene strip of .75mm thickness. It is designed to work as a spacer which is placed on the end of the coach to assist with  gluing the bargeboard into place, leaving a gap as per the real carriage. 
To explain the situation  - In picture A below, the brown carriage is modeled to represent a Double Skinned Roof version with the large End Bargeboard. The Green carriage is modeled to represent the carriage after the double skinned roof has been removed. Picture B shows the side view and it can be seen that the double skinned roof (circled) on the AZ carriage extends a bit beyond the end of the carriage to allow for air to flow under the protecting bargeboard and between the roof space. The carriage on the right is the modified single skin roof version and it can be seen that the roof is somewhat shortened. 

To make the Bargeboard Jig - Take a straight section of .75mm Evergreen strip styrene and cut it to fit between the roof and side walls of the carriage, then add extensions to reach upwards to the curve of the roof. Glue it all together on a sheet of glass or flat board to achieve a flat Jig.
The Bargeboard Jig is put/rested in place on the end of the assembled carriage body after the roof has been fitted. I then apply small drops of glue to the under side of the roof "between" the extensions, taking care not to glue the jig to the carriage body.
 Then slide the curved end bargeboard on top of the jig and press it up under the roof. Once the "tack" spots of glue have dried, remove the jig by carefully sliding it out, then a bead of glue can be applied to the bargeboard and the roof trimmed to match. 
The end result should look something like this!

 Store your Jig so that it may be used again on a similar project.

Monday, January 7, 2013

WAGR R Class Diesel using 3D Printing

The R class has always been one of my favourite locos and just fits into the 1960's timeframe of my layout.

Over the last few months, I have been working on a model of the R class using 3D printing techniques.  While the technology isn't quite there yet at delivering a finish comparable to injection moulding at an affordable price, it does appear to be practical to produce a complete loco using 3D printing, if one is prepared to put up with some imperfections.

No doubt, the technology behind 3D printing will continually improve, so my strategy is to accept the current level of quality as part of the learning process to build a "proof of concept" model.  In a few years time when the quality has improved, I can get new "prints" done and get a new, better model for minimal extra effort.

Today, I received my first complete body for the R class as a 3D print from a company in Belgium called i.Materialise.

The major deficiency of the current (affordable) 3D printing processes is that the resolution is not fine enough to get a nice, smooth surface finish.  The laying of the material as the model is being "built" results in a roughened "striated" surface and also a "stepping" effect on curved surfaces, particularly, in the case of the R class, on the roof.  Whether the quality of surface finish is acceptable depends very much in the individual modeller.

Note the imperfections on the large square radiator intake grille in the form very fine "whiskers". These are due to a minor problem in the design which will be rectified in subsequent prints.

The beauty of the 3D printing process is that virtually all the details can be "printed" as part of the process, providing the details are, of course, built into the 3D artwork in the first place.  In the case of the R, it is really only handrails and horns which will have to be added to complete the body detail. I decided to built the raised numbers on the cab side into the 3D design and they appear to have worked fairly well.

This view of the side detail shows the striated effect visible on vertical surfaces.  While it would be possible to sand the flat surfaces to get a smoother finish, it would be difficult to do so without damaging the fine details.

This top view shows the stepping effect visible on the curved roof.  As my layout is close to "eye level", this effect will not be as obvious when the loco is operating.

I already have a working chassis using a custom-made power bogie from Hollywood Foundry and matching unpowered bogie. The following photo shows the "loco" on the Hollywood Foundry bogies, with very temporary underframe and temporary weighted "fuel tank".

I am currently working on the 3D design for the bogie sideframes and plan to also do the underframe and fuel tank as 3D "prints".  The underframe will be designed to take 2 powered bogies, if desired.

Although I have no intention to produce the R class as a kit, there is the option of making the 3D designs "public" through the i.Materialise website so that anyone interested in building an R class can order "prints" for themselves of the major components.  I can easily make available the ordering details for the power bogie, etc. from Hollywood Foundry, perhaps as an addendum to this blog.  As an indication, the cost from i.Materialise for the 1-piece body as pictured above is $100 + $30 shipping per order.  Delivery time is about 2 weeks from ordering.

I don't have any intention to do the design for an RA.  There are some major differences between the R and RA, including the RA being longer overall.  I estimate it would take about 30-50% additional design time to modify the R design to produce an RA.