Project 16 - Misterton Rebuild

My Misterton layout was originally built in the 1980s as an end to end mainline station over 12 feet. (Misterton is based on Crewkerne station on the L&SWR mainline in Somerset). In 2008 I added more baseboards to make a continuous loop. For it to work I had to turn the layout through 180 degrees, which meant viewing it from the operators side where remnants of non scenic fiddle yards at each end are in full view. Scenically it gives an unfinished look. More critically it limits the length of the station platforms. The scenery is also looking tired after 30 odd years and the track is code 100 whereas the other side of the layout (Hewish Gates) is code 75. All this points to reasons for an uplift.

My plan is to rebuild the layout and lay the track on a transition curve. The platforms follow this gentle curve achieving more length than a conventional lozenge shape with straight sides. This is nothing new and is commonly practised by other modellers.

I drew a track plan and discovered that the transition curve also gives room for extra sidings, something else that Misterton currently lacks.

The new asymmetric 3-way turnout and original single slip on the mainline are as Crewkerne but the rest of the track layout is a stripped down version of the prototype. The existing buildings and some scenic elements will be reused.

I plan to finish the rebuild within a year.  Progress will be reported here under the label 'Project16'. My postings will include modelling techniques, which may be of interest to my Blog Followers.

To Part 2.

3d Print Experiments - FB track finale

I thought it worthwhile to explain why I have gone to the bother of making my own sleepers? Peco track is designed to 3.5mm scale not 4mm. Spacing out the sleepers significantly improves the look but the sleeper lengths could also do with lengthening. Having a 3D printer to hand gave me the opportunity to produce track that looks more authentic and be able to integrate cosmetic fishplates. If  I did not have that I would simply space out the Peco sleepers.

Having worked out the price of the plastic plus rail and a tad for paint there is a saving of about 65p over Peco ready made track unless buying it in bulk where prices work out about the same. So, no real point in doing it to save money.

Whatever we do in sleeper design it is going to be a compromise compared to the prototype because we can't get away from the track gauge of 16.5mm. (I have mentioned elsewhere that I'm not interested in converting modern RTR locomotives to 18.2 or even 18.83 for complete accuracy to prototype).

Here are the track dimensions adopted.

Item	Prototype	18.83mm track gauge (scale 4mm:1ft)	16.5mm track gauge (scale: compromise)
Sleeper Width	10in.	3.33mm	3.33mm (4mm scale)
Sleeper Length	8.5ft	34mm	32mm (Rail to end of sleeper 4mm scale +  track gauge 3.5mm scale)
Sleeper Pitch	2.5ft	10mm	8.8mm (proportionally scaled. 16.5 is 87.6% of 18.83. 10mm emphasises the narrow look of the track too much.)
Track length	24 sleepers over 60ft	240mm	205mm (approx. measured)

Comparison of Peco, DIY and 18.83.

Note: Peco and DIY sleepers look wider because of the shadows.They are all about the same width.

3D Print Experiments - FB Trackbase & Fishplates

When prototype track was made in 60' lengths the rails were joined by metal bars called fishplates. Sleepers at the end of the rails sat beneath the fishplates and consequently were closer together than the rest of the 60' track. That is what I observed for flat bottom rail on the stretch of line I am modelling. Elsewhere the sleepers sometimes sit either end of the fishplates.

The two sleepers close together are 3D printed as a joined pair with integral fishplates on both sides of the rails.

It gives an impression of the bar, is not perfect and bolt heads are a step too far with this technology at this scale (00).

3D Print Experiments - Track Bases (BH rail)

Printing the bullhead rail track base was more problematical than the flat bottom rail base due to the oak key that protrudes from the rail chair on one side. It initially printed all over the place. The solution was in the the design rather than printer setup this time. It is too esoteric to go into details suffice to say it was a question of examining how and what was printed and then adjusting the design for simplicity of form to help the printer do its job.

In this photo I show the track base with a C&L chair (brown) for comparison. The C&L chair, being injection, moulded is finer and a more consistent form that is not easy to achieve for small parts in 3D printing where the plastic is extruded and layered.in free air.

We can see the variation that can result. The leftmost chair is quite acceptable but the one next door has lost a bit of form in the key. I wonder if extending the key might help but then I'll start seeing droop. Still scope for more experimenting but I may stick with this, providing batches are no worse, as it is barely visible at normal viewing distance.

3D Print Experiments - Track Bases (FB rail)

Trying to get more accurate track bed dimensions in 00 I previously spent a lot of time spacing out individual sleepers on Peco code 75, which does gives a more authentic look but the sleeper lengths are still inaccurate.

Now with a 3D printer to hand I wondered how easy it would be to make my own track bases to slide on to the rail. This would be quicker than setting individual sleepers and separate chairs. I focused on flat bottom rail and decided to set the sleeper height same as Peco so that the track was compatible with their turnouts.

The photo shows the printed parts (grey) with correct sleeper size and spacing for 00 gauge. i.e. sleepers 32mm* long and 8.8mm pitch. The dark coloured sleepers are Peco.


The CAD design was relatively simple. The sleepers were designed as joined pairs with integral rail base plates.

Optimising the printer was the difficult part but after a whole day spent tweaking this and that it finally came down to three factors. First to design the rail base plates a little meatier than Peco so that this minuscule part was substantial enough not to be malformed due to plastic fluidity. Secondly to heat the PLA plastic to 185C instead of the default 205C to stop the plastic 'leaking' and causing malformation and thirdly to vary the plastic layer height. The default is 0.24mm, which I retained for the sleeper but reduced it to 0.1mm for the base plates. The base plate clips are very small and need to be built up in very small small layers to preserve their form.

This unkind macro photo showing the rail 'clip' makes it all look a bit rough. The roughness is far less noticeable at normal viewing distance and when painted the lines shown in the top photo will be less prominent too.

Providing the clips have formed correctly they slide onto the rail easily and and hold it firmly.

* Is a 32mm long sleeper correct to scale? Well NO. in 3.5mm scale (being correct for 16.5mm 00 track gauge) a modern 8.5 foot sleeper scales to 30mm and in 4mm scale it is 34mm. To compensate for the narrow look of 16.5mm track when modelling everything else to 4mm the distance from the outer edge of the rail to the end of the sleeper is scaled in 4mm instead of 3.5mm giving a sleeper length overall of 32mm. Visually it looks right even though it is not true to scale overall.

My Hornby Class S15

I wanted this class of mixed traffic locomotive for a very long time because it was common on my stretch of modelled line. Back in the 1980s I looked longingly at the DJH kit, which I think was the only supplier for an S15 in 4mm scale, but it was expensive and could not be afforded at the time.

Many modellers have craved for an S15 and it featured in published wish lists. Now Hornby has just released it, presumably in response to demand. My dreams have been fulfilled and I got one. It is the most expensive locomotive model I have ever purchased but costs well below the DJH kit, once the motor/gearbox and wheel set addons are taken into account.

I have already enhanced it with head code disks, cosmetic screw link coupling, crew and a Zero 1 chip. which fitted easily in the tender connecting to the DCC socket therein.

The accessory pack was tricky to fit, as usual. The front steps had to be set back further than designed so that the wheels did not interfere on my 800mm radius curves.

About making head code disks.

About making cosmetic screw link coupling.

About fitting a Zero 1 chip (class 700 but same idea),

 N15 and S15 (below) - Spot the Difference.
(one is green and the other black, Doh)

3MT Renovation - Fin

Well, the bogie repair broke at the fixing ring but was soon strengthened with a slither of acetate sheet linking the ring to the body of the bogie.

Next job was to find a motor. X03 or X04? I thought either would do but when I looked deeper I discovered these early motors are a bit of a minefield. First thing to understand is that the X03 post dates the X04! Also, there are 3 pole and 5 pole variants and there are gearing variants.

Identifying which one to use was made simple by finding the Service Sheet for the 1956 R59 3MT at Hornby Railways Collectors Guide. This identified X04 as the right one with a worm thread of 6. That website is an excellent source of historical details for Triang and later ranges.

The best place to buy an X04 motor is Ebay but the prices vary enormously from a few pounds to over twenty. Those at the top end tend to have a rewound armature and NEO magnet upgrade. I monitored for several weeks before bidding and winning one at £7.50 incl. postage. This is an original, used motor that works like new.

Some Sellers don't know what they are selling because I did see X03s listed as X04s. The X04s have felt oil pads, the X03s do not and are not so good build quality (I understand from others).

To Part 1.

3MT Renovation - Part 3

Both the front bogie and pony truck, which are identical, had suffered some damage and this one shown has become brittle with surface cracking. The metal,  made from MAZAK, is prone to this if it contains impurities or incorrect proportions of metal. Mazak is an alloy of mostly zinc with some aluminium, magnesium and copper content.

The circular pivot point had fractured into 3 pieces with one part missing. The missing part was recreated using car body filler, as was part of the wheel flange that was also missing. The other grey coloured parts are tailored from plastic sprue and glued in place but these are fragile and will not take a hard knock. The additions have since been matt black painted.

I considered remaking the entire bogie using the 3D printer but as this is a vintage toy I wanted to retain as much of the original as possible whilst it is still serviceable.

The rusted weathering effect on the chassis coupling rods was removed using toothbrush and oven cleaner spray and moving parts then lightly oiled. I may paint the wheels matt black as the natural grey finish is just not right.

Now I need a motor, which might take a while to obtain.

To Final Part.

3MT Renovation - Part 2

The remnants of the original lining, number and emblem were removed by scratching them with my thumbnail. They simply cracked and fragmented.

I did not think that a DIY approach to replacement with the facilities to hand was a viable proposition so I searched Ebay for suitable transfers. It was then that I found a supplier who offered not transfers but a complete refurbishment set for R59 as sticky paper labels. That got me thinking whether or not I could design replacements in my graphics application and ink jet print onto sticky paper. (The ink I use is Epson Durabrite, which has excellent colour retention properties and is water resistant).

The design was straightforward and print quality fine. It is worth noting that sticky backed paper once peeled off the backing is thinner than normal 80gms print paper. When applied to the model its thickness is thin enough to look like a slide transfer.

The pannier tank lining was given black edging and black infill between the white and red lines. The first cut was made along the outer edge of the white line and the panel peeled off as a whole, stuck on the pannier tanks and then a second cut made along the inner edge of the red line and the white panel peeled away leaving a remarkably good quality lining.

The other panels were cut out and fitted, retaining the black inners and numbers.

The 'early' emblem is from a HMRS Pressfix transfer sheet that is years old and lost most of its adhesion. To ensure they stayed in place they were placed on top of a puddle of watery PVA glue and when dry covered with matt varnish.

To Part 3.

3MT Renovation - Part 1

Inspired by the success of the Jinty renovation project I dug out from storage my very first locomotive given to me when I was just a few years old in the 1950s. It is the Triang 3MT, catalogue number R59.

This one has a chassis but no motor. For a while in the 1970s I used it as a static, derelict locomotive. It was also my first attempt at weathering with streaks of rust and water marks applied.

I have already repaired a half broken and missing rear buffer beam with a 3D printed part I designed (shown circled in the photo) and have removed the Humbrol enamel paint weathering effects with tooth brush and oven cleaner spray.

Next job is to repair the lining, number and emblem.

To Part 2.

AMRC expo + Jinty Final + Hymek etc..

There is a connection between these apparently separate topics, as will be revealed.

Andover Model Railway Club exhibition 

The annual Andover Model Railway Club exhibition was visited today and I must say it was an excellent show. I may be biased because I was able to buy every rare thing I needed plus a bit more!

On entering the first hall our attention was immediately drawn to the layouts there, which were of a very high modelling standard, from the vast Thornbury Hill (fine scale 00), with its precision scratch built track laying and a plethora of red buses bringing colour highlights to the scene, to the diminutive Shad Dock (00) and its electric arcing third rail simulation as the EMU shoe contacted the end of the rail.

It is a close call but my best in show goes to Dock Green (0 gauge). It has just the right level of modelling details, so important for that touch of realism in the larger scales. The photos here show the goods shed and office. Note the filing cabinets inside the nicely lit office.

And so to the traders. Probably the greatest variety of traders with high stock levels I have seen for some time.

Jinty Renovation - Final Part

Following on from the previous two posts on this subject we needed to find a complete chassis with motor for the forlorn body. Yes. there were some available on Ebay but we were pleased to see Country Park Models at the Andover show. (I hope I have named the right trader). His is the stand with neatly hung locomotive bodies and separate chassis.

He had a variety of 3F chassis for the Jinty. Comparing the Bachmann and Hornby chassis in the flesh so to speak against the Triang Hornby body that we took with us we could see the higher detailed Backmann would not fit so easily. We opted for the second hand Hornby, which was a second series I believe as the screw fixing was not compatible with our early body.

Having got it home the chassis ran like a dream. Extremely good slow running considering its age and obviously serviced well before sale. The body fixing lugs did not quite fit so had to open up the locating holes in the body. The front end interfered with the buffer beam that I had rebuilt. Some filing of the chassis and body for relief finely resulted in a snug fit.


Hymek

After a very successful running session with my 1970s Hymek diesel loco a couple of weeks ago I left it standing on the track whilst other trains were being observed. On looking round I saw a plume of smoke rising from its power bogie. Quickly taking it off the track I then disassembled it to find the cause. One of the motor brushes had lost its carbon brush and flipped over the armature causing a low resistance that made the other carbon brush overheat (I assume). The missing carbon brush has not been found.

I then started looking on Ebay for a replacement X67 brush and was a little shocked at the prices, about £5 a pair plus postage. Whilst at the Andover show I enquired of Country Park Models who dug out a pair from his stock box and relieved me of £5 for it - the going rate it seems.

Please to say no further damage was caused to the Hymek, which now runs fine with its new brush and I have a spare one to hand for the next travesty.

Class 66

A previous post laid bare my attempts to find a Class 66 in EWS livery. Ebay and a Train Fair I went to had none available, or not within my budget. But I did secure a Class 66 in Freightliner livery. I could not beleive my eyes when at the Andover Model Rail Show there was a trader with three EWS versions on his stand! I left them there of course as the Freightliner had fulfilled my need.

This is not the first time traders at a Model Railway show have come up trumps. I feel Ebay is not the panacea we may think it is for finding those obscure out of manufacture items. It is always worthwhile getting up from the computer to visit a model railway show.

Jinty Renovation - Part 2

47606 just out of the paint shop with late crest emblem applied.

Now we need a chassis.

Jinty Renovation - Part 1

Years ago little bro' gave me his Triang Hornby Jinty (a model dating from 1960s). Now he has taken up the hobby he wants it back.

Neither of us can remember what state the model was in when I received it and I was convinced I no longer had it until on opening a drawer this week I saw its body there in a very poor state. How the buffer beam came to be broken and the chimney, both of which are missing is a mystery and whilst he is convinced he gave it to me with its chassis I can't find it anywhere.

Most people would throw the remnant away since second hand replacements are relatively inexpensive and there are better detailed models available new. But, with a 3D printer to hand I felt it would make an enjoyable project to renovate the body.

From this photo you can discern what was missing and the 3D printed replacements in grey plastic. The dimensions were scaled from various photographs of original models.

Having primed the body with Halfords grey primer (not shown) the light colour has highlighted details of the plastic moulding that are lost to the eye with the black finish. The moulding details are very fine indeed and embossed '3F' markings are revealed near the cab side windows.

Just For The Record

This week I bought the GBL Lord Nelson 00 gauge static model.

As the GBL series comes to an end it will probably be the last Southern, Western Division locomotive I'll obtain from the series. I bought the Mallard, Schools, Black 5, Bulleid, N, T9 and Lord Nelson since the series started. All except the N and LN have previously been posted (use the search box to find them). Mallard was an impulse buy and since sold. Bulleid was motorised. The Black 5 is not Southern but I had an idea to turn it into a BR Class 5, which did run on Southern metal.

One day I may get around to motorising more.

 Lord Nelson and N class Mogul.

Z Gauge London Bus

Having visited Hornby Hobbies Visitor Centre (see previous posts) we then went on to visit the Spitfire and Hurricane Memorial Museum at Manston. One of our party bought this keyring there.

The bus is nicely modelled and the wheels turn. Taking a rule to it I reckon it is about Z Gauge in size 1:220. The attachment for the ring could be cut off unobtrusively.

I was told by the purchaser that other vehicles were also available.

If you model in Z gauge and live in the Thanet area pop along to the museum to have a closer look.

A Few Additions to Hornby 700

First up is the loco crew. I was put off buying a crew by the price of Hornby's driver, fireman and vacuum pipe set at over £6 and to be fair the seated driver in the kit would not fit the 700 cab correctly anyway.

I dug out my box of Airfix people from decades ago and modified a couple to fit the locomotive.

The fireman was originally an old man with a walking stick. I gave him a head transplant from a railway worker and turned his walking stick into a shovel with a square of paper stuck to the stick.

The driver was a standing railway worker. I cut off his legs and fabricated sitting ones from sleeved copper wire. He is sitting at a slant because I wanted him to look out of the cab side window.

This view shows the pair in the locomotive. I used PVA glue to fix the crew. It is just strong enough to hold them in place enabling removal without damage or marking of the locomotive.

Another addition is the head code disks for the Waterloo - Exeter route. You can read how they were made here. They are fixed using double sided tape so they can be removed without damage or marking of the locomotive.

My Hornby Class 700

This is the locomotive I purchased from Hornby Hobbies Visitor Centre in Margate recently.

The LSWR Drummond Class 700 a.k.a. Black Motor lasted until December 1962 and none were preserved. It was used for heavy freight workings. Hornby released the model in several guises including 30315 late crest version, which I bought because the prototype was shedded at Salisbury, which seems fitting for the period and location of my Model Railway. I have a picture of a 700 (30692) in 1960 hauling empty ballast wagons to Meldon on the LSWR main line confirming that the class would have travelled on the line and in the period I have modelled.

I added a Zero 1 chip, which was simple to fit in the tender as shown below. The weights had to be removed to make room for it and despite this the train runs satisfactorily but I suspect on tight curves or uneven track the tender might derail. There is still room in there to add a customised weight.

Out of the box the loco was tested using an old analogue Hornby controller and it was noted that the loco had poor slow speed running tending to jump start. With Zero 1 digital control slow running was restored.

 

So far I have only run it with a 15 wagon train. The loco exhibited wheel slip on the slightest gradient and on the main 800mm curves. I felt that the tender wheels were not particularly free wheeling but I need to investigate further and check the wagons for sticking axles too.

One other problem was a buffer falling off during handling. I glued it back in place.

It is a fine model with nicely detailed and painted cab controls. The cab area has an open aspect that is disconcerting during operation without a loco crew in place. I'll be fitting a driver and fireman.

A Visit to Hornby

A family gathering near Margate gave the opportunity to visit Hornby Hobbies Visitor Centre, on the site of the firm's original HQ and factory.

Hornby is probably the best known brand for model railways, having a long history and the Margate factory in use since 1954. Except, as most in the hobby know, manufacturing moved overseas and the building became a warehouse.



The Visitor Centre is around the right hand corner of the main frontage shown in the photo. It comprises an exhibition, cafe and shop selling the firms products, which includes Airfix, Scalextric, Humbrol and Corgi.

Shop

My interest is in the railway products. I was surprised to see only a subset of the entire catalogue on display. I later discovered that the warehouse had moved elsewhere, and the office staff too. Only the visitor centre remains on site. This might explain the lack of products available.

Fortunately, the locomotive* I was after was available, in all its guises, and happily we had arrived on a rare 10% off day. The price paid was slightly lower than that offered by the Internet discounters! Had we visited the previous weekend we would have been blessed with a 50% off factory sale! Such a shame I don't live close by.

* more about the loco. in a future posting.

Exhibition
 
A handful of model railway layouts, which although landscaped still looked like toy train sets and would definitely appeal to younger visitors whereas older souls may find the static exhibits of toys through the ages more appealing. I saw examples of toy cars I owned from the 1960s and trains I bought in the 1970s, one of which is still used on my layout. Those vintage models on display all looked brand new.

One room is given over to a military exhibit of full size military vehicles and a huge diorama of a Battle of Britain airfield under attack. But this room holds a secret. If you made a pilgrimage to the site because of your love of Hornby and lament the end of manufacture on site and would have liked a tour of the premises well there is a small round spy hole in a door that leads into the factory area. You can see the factory interior that was once a hive of manufacturing activity, empty of machinery now of course.

Cafe

The cafe is a spacious and comfortable rest area We only wanted a drink and had a cappuccino, which was of excellent quality.

I understand Hornby Hobbies are planning to move the Visitor Centre to a new location in Ramsgate. I'm glad I visited whilst it is still at the old factory site.

Enthusiasts Do The Weirdest Things

Once upon a time, hanging on the railway room wall, I had a single piece of ballast stone mounted on a plaque. It was picked up from the track bed of a long closed and abandoned branch line. To anyone else it was a bizarre thing to have but for me it was a reminder of that branch line and the traffic it carried in its heyday. That piece of  memorabilia was taken down and dismantled long ago but I did come across the stone in a storage box recently.

The next piece of memorabilia to cross my path was a railway sleeper with screw fixing holes for 3-hole rail chairs, given to me by a family member. That sleeper was crying out to have the chairs reinstated and so began quite a lengthy project to install a genuine piece of LSWR track as a garden feature (LSWR being my favourite railway company). It was a long time coming, like a year or two, because I had to wait for parts to turn up on Ebay and then win the auctions.

Having bought the rail chairs (made in 1880 and 1881) I discovered their holes did not line up with those on the sleeper and in fact the orientation was a mirror image! I think the holes in the sleeper are for a later BR style of chair.

Initially, I assumed I would need to source rail screws for fixing the chairs and noted the holes in the chairs were much larger than the screw shank so, some kind of ferrule spacer would be needed as well. It was whilst researching this that I found that early LSWR chairs did not use screws but things called trenails and metal pins. This was going to get a whole lot more complicated.

I realised that I had to make the tapered oak trenails since the chances of obtaining them ready made was slim. The tools available to me are quite basic, a Black and Decker workbench, hand saw, electric drill and smoothing wood plane together with an essential spokeshave. No matter how I tried, drilling a hole straight through the middle of the oak for the metal pin did not work out. Either I drilled through at an angle or the wood split.

I decided to drill only part way through and fit a dummy pin, essentially just a head on a short stub. These were designed in CAD and 3D printed in plastic.

Oak keys for holding the rail in the chair were cut and planed from oak. There was a drawing on the web for these but I have lost the source.

The final part to obtain was some railway ballast. No good going to your local builders merchant. They don't sell it. Searching the web for suppliers of reclaimed railway ballast generally threw up large aggregate suppliers who would be happy to sell me a 20 tonne lorry load! But, then I came across Mid Hants Natural Materials a Hampshire supplier who offers reclaimed railway ballast and is happy to supply domestic customers with small quantities. Price is quite reasonable if you are able to collect it yourself. I bought 300 kgs in 10x30kg bags for this project.

The rail by the way is 19th century 82lb/yd double headed. The running edge of the rail is noticeably worn from years of railway stock running along it. I cleaned up and painted the metal work with car paints for a close match to real weathered rails.

A nice piece of railway heritage in the garden.

Is that weird or what?

'N' Thornycroft J Class Lorry - 3D Print. Part Fin

The cargo body folded canopy was glued into the cargo body and its frame formed from 'skirt' (see part 5d for explanation). Painting and lettering was applied and the final result is shown below alongside a 1p coin.

Not too bad after all. The troubles with 3D print mentioned previously are far less prevalent for larger objects.

To Part 5a (start of series).

'N' Thornycroft J Class Lorry - 3D Print. Part 5f

I hate SuperGlue. It's been troublesome getting these small parts to stick. Why does the glue stick skin better than plastic? (By the way this is PLA plastic and does not work with polystyrene glue) I'm finding I have to wait a long time for the Superglue to fully go off and once it has held its a b****r to break apart if a mistake occurred. The petrol tank is a case in point. I placed it in the correct position on the bulkhead, applied pressure to create the bond and set aside. Came back later to find the tank had slipped down the bulkhead and set hard. The only consolation is it is barely visible once the canopy is in situ.

Photo 1: Cargo body and battery boxes assembled and step glued to the chassis.

Photo 2: Rolled canvas doors with integral pillars applied. I painted the wheel sets off the lorry as once they are in place it would be difficult to access their rears. At the same time I painted the canopies,which are a lighter colour than the rest, although not particularly obvious against the darker wheels. I may need to over paint a lighter colour.

The canopy with strapping  is removable, sliding over the cab rear wall. I might design and make a folded canopy as an option.

Photo 3: Rear wheels, drive shaft and exhaust pipe glued in place.

Photo 4: Front wheels glued in place and rear mudguards. The latter are strips of 'brim' curled over a metal rod to form the curve and glued to the underside of the cargo body. Head lights cut from the plastic rod and glued to side of radiator.

All looks a bit rough I know but bear in mind the photograph equates to your eyeball being about three inches from the lorry, whereas the optimum viewing distance for 'N' gauge is about 2 feet.

In the next posting, painting and final assembly.

To Final Part.

To Part 5a.

'N' Thornycroft J Class Lorry - 3D Print. Part 5e

The remaining parts were printed, cleaned up and assembly begun.

Photo 1: The complete kit of parts, including skirt and brim (see part 5d). There should be a window in the rear wall of the cab. I left it out because it is hidden by the canopy on the model.

Photo 2: Two holes were drilled in the cab floor for steering column, gear lever and brake lever (the latter two in one hole). The steering wheel was glued to a length of 'skirt', fed through its locating hole, glued and excess cut off. Similarly with the gear and brake levers. Front and rear wheels were glued to their axles, the front axle being a length of 'skirt'. The petrol tank was glued in position behind the front bulkhead.

Photo 3: Two lamps were cut from the rod and glued to the front bulkhead and the cab glued in place on the chassis. The four cargo body supports were glued on top of the chassis frame. Mudguards fitted to the front wheels. I may treat the rear wheel mudguards differently and will leave these until later.

Photo 4: Lengths of 'skirt' are used for cab canopy strapping and same for the step, which is cut from a 'brim'.

Assembly continues in the next posting.

To Part 5f.

To Part 5a.

'N' Thornycroft J Class Lorry - 3D Print. Part 5d

This photo shows the set of wheels, petrol tank, steering wheel and rod. What a mess!

Each component was printed with a brim, which helps these very small components stick to the printer bed. The brims will be cut off and part of the long one on the right will be used for the step up to the cab.

Next thing to notice is none of the holes in the wheels formed as the printer could not cope and the conical shape of the wheel hub is just a blob.

They look useless but with a bit of filing and drilling they become useable. You may think this defeats the object of 3D printing but at least the wheels are round!

In the next posting the remaining components will be printed.

To Part 5e.

To Part 5a.

'N' Thornycroft J Class Lorry - 3D Print. Part 5c

This is the raw print of the chassis on the print bed of our 3D printer.

A few comments about the environment. Each time the machine is powered up the printer needs to be calibrated to take into account any deviation in levels between the X, Y, Z arms and printer bed. This may be a peculiarity of our printer design and I don't know if other printers have the same need. In theory it is simply done by loading a set up file into the controller but I go a step further and manually set the print head height above the middle of the bed. Too low and the first layer or two will be too thin, too high and the plastic will tend to float free of the bed.

The bed has a glass working area that is covered with kapton tape. This is a high temperature tape that has good adhesion properties for the plastic as it is laid down. The tape looses its effectiveness after a few prints and needs to be replaced, but its life can be prolonged by wiping vinegar over the surface before each print, which acts as a cleaning agent. Some people have cited success printing directly onto the glass.

The chassis component above shows thin plastic whisker deposits and it is a bit blobby. This is a common occurrence, particularly for small objects. I dare say further experimentation with printing parameters may reduce the problem but it is generally the case that some post processing with files, scalpel and drills to remove blemishes is required. Indentations can also occur and if undesirable will need to be filled with plastic padding.

I mentioned in the previous posting that a skirt is formed around the component. It can be seen in the photo above. In this example it is ragged and not suitable for rod and bar components. You'll have to read Part 5b to understand this.

Here is the finished component after the rubbish is removed. A one penny piece is alongside to show how small the chassis is. If you think it looks a bit rough then it pails into insignificance at normal viewing distances.

Sometimes the component printed may be very poor. In this case either the design would need rework, the printer parameters changed or simply print the component rotated through 90 degrees corrects the problem.

The cab canopy was a case in point.

The photo below shows two prints of the same cab canopy. The right hand version suffered badly. When it was printed turned 90 degrees it held its dimensions correctly. (version on the left).

Note the indentation on the left hand version. This could be filled with plastic padding but it is not necessary here. The canopy on the prototype is in fact canvas pulled over a frame and exhibits depressions between the frame bars. This I recreated with a file for the finished component shown below.

More component printing in the next posting.

To Part 5d.

To Part 5a.

'N' Thornycroft J Class Lorry - 3D Print. Part 5b

There is logic behind deciding on how to disassemble the lorry into individual components. The main consideration is the printing process itself because the extruded plastic is initially soft and any parts of a component that overhang or have an air gap beneath are likely to droop due to gravity. Supports can be built in to overcome this but it just means more work to cut and file them off the finished component. Looking at the complete lorry I found a workable split line between the chassis and body that avoids overhangs.

Another consideration is the scale of the object. How much detail is practical to print in 'N' gauge? Not a lot I wager and that which is barely seen and has complex curves in the prototype can be designed as a rectilinear block, if at all.

These images below show all the parts designed in CAD for the lorry and explanation is given below.

1. The chassis

This has most detail. I designed it upside down as that is how it will be printed. The image below shows some of the lorry parts included in the design. Note the block design of the leaf springs - not like the prototype but do give a resemblance of springs and are fit for purpose in the model. The strut with the hole does not have the curvature of the prototype but it serves its purpose to give rigidity to the frame and facilitate passage of the drive shaft through it.

2. Wheels, steering wheel and petrol tank

These were presented in Part 5a of this series.

3. Radiator, engine housing and cab

As shown.

4. Canopies

On the left is the opened cab canopy, deliberately oriented this way for print to avoid overhanging parts. There is a cavity in the back for the canopy to slide over the rear wall of the cab. The other part is a folded canvas for covering the cargo body. This will be stored in the open cargo body.

5. Cargo body, supports and battery boxes

I decided to model this without a cover in place thinking that the lorry may have been delivered to the customer like that. I have seen photos as such, which also show the cab canopy folded up vertically on its frame.

The supports stand the body off the chassis frame and the battery boxes hang beneath the body.

6. Lamps and rolled canvas doors.

This is just a rod that will be cut with a scalpel into slices and fixed to the model to represent the four front lamps and rolled cab doors.

7. Rear Axle

As Shown.

8. Left and right mud guards

The tabs on these are glued to the backs of the wheels.

9. Various tubes and bars

This is not a CAD design. It is the redundant skirt created during the print process. What happens is a string of plastic is laid around the perimeter of the piece to get the plastic flowing before it prints the actual component. This is a very fine thread of plastic that is ideal for use as 'N' gauge struts, drive shaft, axle, gear stick etc..

In the next posting I start the print.

To Part 5c

To Part 5a.

'N' Thornycroft J Class Lorry - 3D Print. Part 5a

In this series of postings I shall be making this:

as a kit of parts to a scale of 1:148. Now that is small and will stretch the limits of our printer capability, as you will see.

First thing we need is a dimensional drawing. A chassis dimensioned drawing is on display at Milestones Museum Basingstoke. With regard to the bodywork I shall use the specified wheelbase dimension to scale the above photo.

Now I need a Computer Aided Design Application, one that can create 3D models and has an export facility for Stereolithography files. This is a data file that defines 3D products built up one layer of material at a time, being what 3D printers do. I reviewed popular open source CAD Applications and choose FreeCad, which seemed to have good tutorials. Help is also available from YouTube videos. Even so, CAD can be quite complicated and the method I used from the plethora of options available in the Application may not be the best or even most effective means. I used a facility called 'Part'. The drawn model is created by adding and subtracting geometric shapes rather than starting with a 2D line drawing. It sounds a simple method and it is, although I have not yet needed to create convoluted shapes.

These photos demonstrate the principal as applied to the front wheel of the lorry:

1. A blank cylinder 5.94mm diameter and 1mm thick.
2. Another cylinder is superimposed (height arbitrary but, more than the first cylinder) that is embedded 0.5mm into the first cylinder.
3. The second cylinder is 'cut' from the first, which leaves the impression it made in the first cylinder.
4. A cone is added, representing the hub of the wheel.
5. 9 more cylinders superimposed and embedded the full depth of the part.
6. the 9 cylinders are cut from the wheel leaving an axle location hole and 8 vents.

I decided to create a group of objects in the same drawing for quickness although it is quite acceptable to have separate drawings for each object.

On the left are the four wheels, a steering wheel and petrol tank. The steering wheel is solid as it is not practical to print the spokes for something this small. Each rear wheel is a set of two in tandem with the rear one being a solid disc. The right hand image shows how the wedge shaped petrol tank was made from two rectangular boxes. The angled box is cut from the other to form the wedge.

Having exported a steriolithography file it needs to be converted to a G code file that is specific to the printer in use. It sets parameters that heat the plastic, moves the printing nozzle in x-y-z planes (within the bounds of the available printing bed) and extrudes a string of plastic the length of which is set for each segment of the printed object (the object is created by laying down strings of plastic in rows and layers).

The conversion utility is Slic3r. The utility needs to be configured and a configuration file compatible with our printer was supplied by the printer manufacturer. All we need to do is adjust parameters when necessary for optimum printing of specific objects.

The next posting will present all the remaining drawn parts for the kit.

To Part 5b

To Part 1 (About the printer)

Best In Show

I attended the BNHMRS 32nd model railway show on 14th/15th March 2015. I usually give a review of shows that I visit on this Blog but, this time it would be inappropriate because together with my son we were exhibiting our Cliddesden layout.

The BNHMRS show must be one of the largest in the south. This year there were 25 layouts on show. A specially invited guest of the club was Steve Flint, editor of 'Railway Modeller' magazine and he was given the unenviable task of judging Best in Show.

We were happily operating our little layout when we became aware of an increasing throng near us and then Steve Flint stood up on a bench and gave a speech, the content of which escapes me now because he announced that Cliddesden was to be awarded best in show! We were in utter disbelief as we were ushered to the front of our layout for shield presentation and photographs.

It was totally unexpected and begged the question why? Our layout is a simple loop with two sidings on a board 6 x 3 feet.

There is little doubt in our own minds that the scene we created looks right and realistic. The fact that it is closely based and scaled from a real location helps and years of modelling experience is another factor. But there must be more than this that warranted Best in Show.

Listening to comments from the general public as they perused the layout gives some clues. Lots of people gave praise saying it is well modelled and they appreciated the detailed scenes we replicated from real events of the period. (We have a screen presentation running alongside the exhibit that helps visitors understand the history of the station and the events that we modelled). There were also those who had some affinity with the line and came especially to see the layout, like the gentleman who knew Bert White, the last station master of Cliddesden and another who did a project on the station and showed us original documents related to the line and gave us a gift of a rare artistic print of the station in 1916, coincidentally the exact period of our model! This level of interest arose because we were exhibiting a scene that has roots in the local area.

There is no doubt in my mind that a model railway closely based on a real location can be more satisfying for the creator than a fictitious location because the history that must be researched adds interest and a sense of purpose to the project. For the visitor who knows of the area it awakens faded memories of happy times (hopefully). It was really heart warming to hear their stories.

We had a great time at the show and to cap it all it was my Birthday!