Model Engine Works: 2024

Tuesday, 31 December 2024

00n3 & TT:120 Chassis Conversion

Kato 11-110 Tram Chassis Conversion to 12mm Gauge

It's been a long-term goal of mine to find a readily available economical chassis for 12mm gauge use. This would give 00n3 narrow gauge modellers an equivalent to the Kato tram chassis that 009 modellers have, allowing entry-level tram engines to be accessible at a reasonable price. As a side note, this may also suit modellers of the TT:120 scale.

After working on various alternatives for some time, I finally asked myself: could I convert the Kato chassis and regauge it? So that's what I did ― and it's simple to do, using the new 11-110 version with the cordless motor. The only new bits needed are some small spacers to reset the gauge of the wheels. The rest of the work involves modifying what you have with the existing chassis.

The best way to explain this is with pictures and notes, so I have attempted to do this in the following instructions:

1 Remove the couplings from each end of the upper shell. They are clipped in place, so pull off quite easily.

2 Remove the balconies from each end of the upper shell. I cut these off with a pair of Xuron Track Cutters ― they cut the plastic cleanly and do a neat job.

3 The next step is to remove the four axel boxes from the upper shell. There are two cuts on each one: first a small nick at the inner end, then cut straight across the top. Then clean the cuts off with a craft knife.

This is important as the upper shell needs to be clear of the pickups.

4 The lower shell needs to be trimmed to allow clearance for the bends on the pickups. This requires two cuts in each corner ― it may be easier to cut these with a kraft knife. There is also a bit to trim off each of the end tabs (the small lip that sticks up).

5 Take the metal pickups and using a pair of fine pliers bend these at each end to form a very slight Z. The idea is to induce a 1.4mm offset to work with the wider wheelsets.

I have noted that this can be difficult to get consistent, and I have developed a press to achieve this.

The following shows the method to use the press:

It has a core into which the pickups are inserted with the outside facing the arrow. It will centralize when pushed right down into the slot. Fold up the sides, and press these together to form the bends in the pickup. The metal is soft and bends easily.

I can supply a press on request at modelengineworks@outlook.com

6 Next take the wheel and pull the metal parts away from the central plastic tube and gear. They are only a very good push fit so will not take a lot of force to remove.

7 The next step is to add small packing disks that are 1.4mm thick to the metal wheel pins. This will leave just enough of the pin to push back into the original tube. These can be made from a Plasticard sheet using a hole punch to make the 4mm diameter disk, then drilled with a 1mm central hole so it is a push fit to the axel. I made some on a 3D printer, and can also supply these on request at modelengineworks@outlook.com. The results are similar using both methods.

8 Return the wheel sets to the chassis ― they are not handed so they fit at either end.

9 This is the start of the fiddly jobs. The pickups are returned to the chassis: these need to be kept in their correct position while the bottom shell is clipped on.

10 It is important to get the bottom shell correctly orientated to the metal chassis. There are arrows on the shells that point to the front of the position where the worm gear is located.

11 Before replacing the top shell: as the motor is loose at this point, the red pad on which it sits can become dislodged, so make sure it is correctly positioned in the metal chassis. At this stage to keep the motor in place, I added a small strip of black insulation tape around the hole unit to keep things in place and to test if the chassis runs OK.

12 After testing, the top shell can be returned to the chassis. Look out for the orientation arrow, and then clip this in place.

13 Now test if the chassis runs. If there is a problem: I have found that the areas above the pickups where they are bent out may need more clearance ― they need a bit of free play up and down. The other area that can cause issues is the pickups being too tight on the wheel: these are best with a little free play or less pressure on the wheels and may need to be eased out from the wheels.

The conversion has now been carried out successfully by several other 00n3 modelers.

They have found that the pickup is a difficult part to bend by hand. Also, these must have the correct clearance above the wheels to allow movement. It is also important to get the bottom plastic cover on the right way round, or this will cause the gears to bind with it, or not clip in place.

See the conversion by Paul Titmuss running on his 00n3 layout 'Lispole' on YouTube.

A copy of the press and spacers can be supplied on request at modelengineworks@outlook.com

Sunday, 14 April 2024

009 Tram Shelter

On the bus route to work from Huddersfield to Elland, I kept noticing a very unusual bus shelter. It stuck in my mind because it looked so ornate and out of place. On one of my journeys in 2020 I walked to the bus stop just to have a closer look and I was not disappointed. It is a fantastic little building, built of wood and painted in cream and red with a grey slate roof and lots of little details. Before my bus came I did a quick measure and took lots of photos. It was a much more interesting wait for a bus than normal that day.

I did a little research into the history of the building. It was built by the Huddersfield Corporation Tramways in 1896, which was the first local-authority-run tramway service in England and was built to the unusual gauge of 4 ft 7 3⁄4 in to attract traffic from neighbouring coal tramways. The shelter was presumably repurposed in 1934, upon the conversion of the Linley and Outlane line to trolleybus. The entire Huddersfield network was converted over the 1930s (the tram network officially closed on Saturday 29th June 1940), and was itself replaced - and the shelter once again repurposed - when the trolleybus network was superseded by buses in 1968. Unfortunately, as with most of our very nice Victorian infrastructure, the shelter became unnoticed, unfashionable, and neglected, despite being Grade II listed in 1977. Its fortunes changed in recent times: in 2015, the West Yorkshire Passenger Transport Executive applied to restore the shelter to its former condition and H.C.T. colours of vermilion and cream. This is why I had noticed it. I have since found out that the shelter once had a central coal stove and the roof apex once had a chimney, not the finial that nicely finishes off the restored roof.

Fast forward to December 2023. I had just got a new 3D filament printer and was looking for something interesting to challenge both the machine and my drawing skills when I remembered the shelter. It had a good level of detail and an interesting shape. So off I went and disappeared for several hours doing the drawing. I then had the new dark art of “slicing” software to navigate before unleashing it on the printer.

The results surprised me. They were good, not perfect, but a good basis to work with to create a model with a level of detail at a 4mm scale. I wondered if I could go smaller so tried a 3 mm scale and then 2.53mm TT120. They both worked but with some of the finer window details removed as the printer's 0.4 mm nozzle and 0.1mm layer thickness was just not fine enough. Also at the two smaller scales, the details are just not that visible.

The 4mm scale version I did in three sections: the roof, walls, and floor. It worked well for printing and allowed the interior to be accessed for painting. For the smaller scales, I just did the roof and walls, though I am sure a floor will print with the floorboard details.

There was a little bit of cleaning up to do around the windows, and also the underside of any overhangs are challenging to get smooth on the printer. I have found that small needle files are a very good tool to smooth things out in these areas. Printing on a fine setting does give a good finish to the model and although there are areas with some fine lines these are not difficult to overcome. When preparing the model for painting I used a spray matt primer in either white or grey then gloss spray lacquer, which has the effect of levelling the surface. I applied two or three coats of each and this gave me a smooth surface to paint on.

Painting the first model I used Vallejo acrylic paints, each thinned with a little thinner medium and applied in multiple thin coats and washes to highlight shading. I decided to try and go with the current colours of the shelter and used a mix of 70.926 Red and 70.947 Dark Vermillion on the lower panelling and details, 70.837 Sand on the windows and upper details, 70.826 Black Grey on the roof and floor concrete base. This was mixed with 70.951 White to create a light grey for the concrete base and a mid-grey for the roof tiles. It was also used to dry brush over the roof area. The floor was based out with a light grey and then a black wash to get between the boards and finally dry brushed with the sand. For any areas with lead flashing, I mixed a bit of the black grey with some 70.997 silver to give it a metallic grey look.

It has been an enjoyable venture into the world of home printing my own models and learning a new skill, and though it is not to be compared with commercial printing such as Shapeways, it has a place for those of us who like the challenge of trying something ourselves. I picked a filament printer as it uses less messy materials and takes up less work space than resin printing, so would do for me at this time. Things are changing fast though, so that will change I am sure.

Based on the original panels which I have drawn in a modular fashion, there are some variants of the original shelter also - these include a hexagon smaller version a double-fronted rectangular type and two-handed smaller rectangular versions.

If you like the model and would like your own copy please get in touch with me at modelengineworks@outlook.com and I will do my best to help.