Recently I have been building a train set, I will blog the progress, in six parts, highlighting how I get certain things done.

• Part 1 – Design and Woodwork
• Part 2 – Electrical design.
• Part 3 – Mechanical servicing
• Part 4 – Construction
• Part 5 – Painting of buildings and natural elements.
• Part 6 – Embedded computing and setup of DCC controllers.

Base Setup

Firstly I am designing a track that is movable from a storage hook on a garage, to a pool table in my living. This requires a baseboard, which I constructed with three cross breams, an MDF sheet and Tasmanian oak edging.

Designing the layout.

I used  the Simple Computer Aided Railway Modeller (SCARM) to plan my layout.  A read over an old German railway construction guide gave me a lot of practical hints as to what made a good layout.

Layout as viewed from the front.

layout as viewed from the rear.

Setting up the levels for hills and track.

The frame work is wood and MDF. Before getting into some neat tricks, lets look at a time lapse.

Steps:

• The track plan is printed 1:1 on a standard printer using 40 pieces of paper, there is a trick to doing this in SCARM.
• The layout is placed on the board and a toy train is run over it, just to get a feel for what it will be like to interact with.
• Spacers are cut on a table saw, so that the MDF can be set to the correct height for the track.
• Contours are cut from MDF using a jigsaw and the track carver up and placed on top of the MDF.
• Everything is assembled, a brad gun and wood glue is a quick way to get this done. I screw down the MDF, without glue, so I can  run wires later.

Train storage Cabinet.

I built a cabinet to hold the trains and keep them dust free.

• It is build like a picture frame, but I used the table saw to create a ‘grove cut’ on the frame.
• The grove allows two pieces of acrylic to slide like doors in the frame.
• If your not 100% on table saws, this video is terrific. (10:20 explains grove cuts).
• Using acrylic instead of glass lets me insert the doors after assembly (acrylic bends)
• The wood is Tasmanian oak (to match the table) and the finish is Linseed oil followed by a glossy furniture polish.
  • Frame Cutting  in Tasmanian oak is fraught with random peril. If you cut the long edges first, you can reuse failed cuts for the short edges, saving timber.

Rule of thumb. If you would you would not be happy with this kind of material on the surface of whatever you are coating, remove your finger prints.

• So a very thin coat of paint is 0.02mm, but often thicker.  So wash your hands, then it’s probably OK to touch. But don’t “Pizza and Paint”.
• Thermal paste on your CPU is 0.07mm  to 0.12mm thick, So Pizza hands are a definite problem. A single normal finger print may well produce a small but noticeable effect to cooling. A well handled CPU with a few prints is probably not good, you would not leave scraps of plastic wrap on the CPU after all.
• Some glues may dilute your finger print and not care (super glue). While other (silicone adhesives) will probably bond poorly.
• Solder – The NASA soldering standards (NASA_STD_8739 .3) state: “When handling metal surfaces that are to be soldered is unavoidable, clean, lint-free gloves or finger cots shall be used. “. Many commercial soldering standards also follow this advise for handling of both solder and parts.
  • Whats interesting is that some manufactures are particularly concerned about what is on your hands (moisturisers and hand lotions cited as being particularly problematic to solder).
  • The finger print contamination of solder joints is often resolved by just keeping the joint hot until the solder takes. This extra heating burns of enough contaminate to allow solder to flow, but can damage components amongst other problems.
  • UPDATE: The new IPC standards (IPC-J-STD-001ES), which NASA, and many other companies, have adopted, don’t mention fingers or gloves specifically. They only broadly reference that handling mechanisms stall not contaminate the board or parts.

This cabinet cooling hack is based around the Artic F12 TC series fans because this fan has a built in temperature sensor. It’s not a hardware hack at all. but a ‘cabinet hack’; so don’t be afraid to give it a go if your not into electronics.

These fans are awesome for cabinets (cooling your amp. game console, etc) because they:

• have their own temperature sensor and speed up accordingly;
• are basically silent until needed;
• use a fluid dynamic bearings (much longer lasting than regular fans)
• know when to speed up (temperature profile is pretty good);
• are long lasting;, with a 6 year warranty;
• less irritating and deeper than normal fans (sounds like a fridge) when going full ball.
• are not expensive.
• The specs say it can run on 5v so USB power may be an option.
  • Edit: I just tried one out on my bench-top power supply. It did not move until about 6.5v.

Links:

• ARCTIC F12 TC
• ARCTIC F12 PRO TC

For this project I am using my DIY honey-comb fan guard (details here) to protect the fan and install it into a cabinet.

Step 1: Plan it out.

Some things you need to do first,

• Figure out which way you are going to position the fan.
  • Many people have the fan blow into the cabinet so that dust is not drawn in through every crack
  • You can then protect the from sucking dust in with a screen
  • Note: You don’t want the fan working against another devices fan, which it sits behind
• Route 12v power to the fan pins and check it spins and works before installing.
  • Don’t worry about an off switch, it will idle silent when your devices don’t need cooling.
  • You can use a 12v wall wart.
• Look into dust catching foam
• By my testing, this neat little fan in question draws 30mA on idle and about 100mA when going full throttle.
  • So look for a 12v wall-wart in the 150mA to 200mA range.
  • Also Red is positive, black is negative, and don’t do anything with the yellow.

Step 2: Cut your cabinet.

Take care, with this.

• Use a 120mm hole saw and a stencil (I have one here).
• Drill from the outside in
• Unplug everything in your cabinet, don’t dill through into your favourite electronic toy.
• Do the hole-saw first, then the other four holes.
  • Then, if your hole saw moves of target, you can reposition your stencil.

Stencil (on right, print at 300 dpi. The big circle should be 120mm in diameter and the screw holes 105mm centre to centre.

Step 3: Assemble and Enjoy.

•  You may need a guard on both sides, to prevent errant wires entering the fan.
• Be careful the temperature sensor is not damaged (its breakable, and the fan stops if you smash it)
  • Generally tuck the sensor out of harms reach.
  • Place your temperature sensor on the device if you need more aggressive cooling.

I originally designed this as a two shelf unit, but trivially built it as a three shelf unit. The indents in the shelf place McCormick brand spices (Australian jar) at a pleasing interval, and seat them snugly. The rail is at the right height to keep the label viable and support the jar, without making removal difficult.

Machining was done on the artifactory‘s  CNC-router.

Final Result

Blue Prints

Image (click for larger)

Download

DXF (cad file)  here

Construction Notes

NB: I could not quite let go of my old school woodworking tendencies, so I made all tabs fit the slots exactly… This meant that after the router made its cut, the wood would expand a little and not fit in the slot. This is just what I wanted, preferring a bit of sanding at the end, so all would fit very snug. Nowadays I would wind back the slots 0.3 of a millimetre and let the glue do the rest.

The spices escutcheons I ended up 3d – printing and painting.  Nowadays there are plenty of 3d printing services should could offer a much better finish.

The stain I used was Wattyl Wood Gel – Honey Oak. I like how easy and fool proof these stains are. The results not bad either.

Photos of actual parts.