Lynton & Lynmouth 4mm scale, 8mm gauge

[CF MRC]

I have always had a soft spot for the Lynton & Barnstable railway: a narrow gauge railway but with standard gauge style.  Over the last couple of years we have holidayed a few times in N Devon, visited the area and, of course, the preserved railway itself. A grand little line, that is becoming a great success with outstandingly pretty countryside around it.  Many of you will know that the line closed in the mid 1930s but had a significant investment by the Southern Railway in the ‘20s, before closure. There is a massive amount of information available on the line.

 

Anyway, following this N Devon inspiration, I have acquired some 4mm scale L&B bits and pieces.  I have started a diorama of Lynton, usually working in the camper van when we are away - and with a very slow rate of progress; at this stage it is just the engine shed area to see if I like it (the shed is on the left in this image). 

An Australian company, Outback Models, has made some very reasonable printed and laser cut card kits of the buildings at Lynton and that is the basis for this model. Printed paper kits can be significantly improved by extra embossing, as shown by the stonework and corrugated iron roof. There is a lot of weathering and detailing yet to be done.

The engine shed track has been made to correct gauge, 8mm, with code 40 FB rail - OO9 looks rather crude when representing a 2’ line - and the area has been blocked in with grey paint.  Keith Armes has produced a Templot plan of the track work. lynton_no_bkgrnd_track_v2.pdf

 

lynton_no_bkgrnd_track_v2.pdf

Quite a different style of modelling to CF, but it will be quite fun to start adding the details and learn some new scenic techniques for rocks and moorland. Quite a good distraction for the time being, from not being able to work on CF.

 

Tim

[CF MRC]

I have cropped and enlarged this interesting picture of the Barnstable-end doors at Lynton.  The ash had been shovelled out of the ash pit, but a leaking hose pipe has evidently made a couple of puddles - something well worth simulating...

 

I don’t think I have ever seen model puddles that were totally convincing, perhaps due to a varnish meniscus, non shiny surface to the water or maybe they’re just in the wrong place.  So I put my thinking cap on: in fact this little project is helping me to practice some quite useful techniques. To represent the puddle I first of all gouged out a depression from the card surface and painted it dark gray. 

 

This was then filled with epoxy resin (Araldite Precision) to an excess, taking care to mix the resin without air bubbles and to let it stand under a lamp for a short while to become nice and runny. 

 

The top of the water was then represented by a microscope slide cover slip which is 170um thick, gently laid down on the resin, with just a little pressure to squeeze out any excess.

 

Once the resin had cured, the coverslip was broken away with the edge of a scalpel. Somewhat annoyingly, this actually took some of the surrounding earth away as well, whilst the cover glass remained stuck to the main puddle. 

 

The ground was therefore made good with a coloured plaster slurry to just above the top of the coverslip. 

 

Now obviously a loco shed area would be covered in ash and this was represented by ground up ash from my miniature traction engine.
Whilst ash powder can be held in place by a layer of PVA glue to some extent, a more natural effect can be produced by using sprayed matt varnish to help lock the loose ash together. This would also represent the surface where the puddle has started to dry out.  However, I didn’t want matt water over the whole puddle, so this was covered with PVA glue, incorporating a strip of paper to remove it more easily after the spraying. 

The end result gives a glass-like reflection from the water - funny that - and avoids problems of menisci and an irregular surface.  The building itself needs further work around the roof (just resting in place in these images) and more details. 

 

Quite a lot of work for two little puddles, do you think it was worth it?

 

Tim
 

 

Edited May 9, 2020 by CF MRC

[CF MRC]

I have made good progress today on the enamel signs on the engine shed.  I have trawled the internet for near equivalent images of prototype enamel signs to those shown in the L&B bible, Measured & Drawn as well as any photos of the station that I have on file. These images were then captured as a photo with a screen shot and then cropped to the border, with other image distortions corrected using the iPad photo manipulation software: it is remarkably powerful, with clever adjustments for distortions inherent with a phone camera lens.  This image shows one of the rather poorer specimens. 

In fact quite a lot of the prototype signs showed major damage and rusting and so they were cleaned up and touched up after importing the photos into NotePad Pro, a drawing package, again on the iPad: looks pretty crude at this magnification!

 

These rectified images were again re-saved into ‘Photos’ to then be imported into a slide in PowerPoint on my laptop.  Photos can easily be manipulated for exact size in PowerPoint and borders of the correct colour re-instated, where these were cropped.  The slide was made up of all the enamel signs I could find for Lynton and one extra for self promotion: this was finally saved as a PDF that can be printed off on an A4 sheet at correct size for 4mm scale.  

The signs were run off at high resolution on matt photo quality paper on my inkjet printer.  I am not convinced that signs should be glossy in this scale: the photographic effect of the enamel is sufficient.  The sheet was given a light spray with Tamiya light grey undercoat to seal it on the back and the edges touched in with a felt tip pen once the signs were cut out.

The signs in use at Lynton varied over time and they certainly give a lovely splash of colour to an otherwise quite lacklustre building.

Tim

Edited May 11, 2020 by CF MRC

[CF MRC]

 

Had to get me name on it somehow. 

Tim

[t-b-g]

You have many areas of interest Tim. Another lovely bit of modelling.

 

Will it ever turn into a little working layout?

 

Tony

 

 

[CF MRC]

It could well do Tony. It’s a relatively compact station and the scenery around it outstanding. It would be an interesting challenge to do it justice.  This is quite an entertaining project that could utilise some novel techniques: it’s 40 years since I modelled green fields and the modelling world has moved on a bit since then.

 

Tim

[CF MRC]

Bits & pieces courtesy of Modelu. 

Tim

[roundhouse]

The engine shed looks lovely and look forward to seeing your future buildings of this location especially as I am currently building Blackmoor station in 009. The enamel signs are one of the upcoming tasks that I will be doing to add to the station.

[hayfield]

Tim

 

A lovely bit of modelling, two friends of mine are volunteer coach builders for the L&B, so I get regular updates

[CF MRC]

It’s a scorching hot day at Lynton, but the engine shed is a few degrees cooler in the shade. 

Come the evening, the new electric light installed by the Southern Railway, gives a bit of help to see repairs. 

I’d like as many fivers as the number of times my hand has been caught in the Tommy bar on the blacksmiths vice, when I was a kid. 

Tim

Edited May 17, 2020 by CF MRC

[CF MRC]

One advantage of following a prototype as well covered photographically as Lynton is that weathering is rather easier.  The shed now has its roof permanently fixed and the ends blended in: the heading photo shows how this was in Southern days. 

At the Lynton end, the smoke staining was rather more prevalent: the only outstanding details are now the point rodding, power line insulators and water pipe at this end. 

The building is now awaiting the rest of the world around it. 

Tim
 

 

 

[CF MRC]

I have made a start on the axles and wheel sets for Yeo, the first engine for Lynton.  The standards are based on those of the 2mm Scale Association, but minus 1.42mm.

 

The Heljan wheels are actually very fine as made, but to work in the narrower FS flange-ways require a thinner flange. The wheels were thinned mainly on the rear and a little bit off the front face, being held in a step collet. There is no need to modify the tread diameter, so maintaining concentricity. 

The new 2mm axles were turned from watchmakers pivot steel: it is very hard and has a highly polished surface. A 1.5mm diameter by 1mm deep shoulder was turned on the end using a TC tool. 

The fly crank webs will be made next using 1mm thick steel, fitted up against the shouldered axle.  What will become apparent, when the valve gear is complete, is that the engine won’t look as if its got it’s elbows sticking out, compared to the commercial model. 

Tim

 

Edited May 19, 2020 by CF MRC

[CF MRC]

The crank webs were made by drilling a strip of 1mm thick steel with the relevant 1.5 & 0.9mm diameter holes, just using the dials on my co-ordinate drilling table for setting out. Lots of cutting oil was needed, and a very gentle action with the small TC drill.

The strip was then tidied up prior to chopping off the individual crank webs. 

The use of two twist drills helped to hold the stack of cranks together for filing in the vice and also indicated that they had identical throws. 

The cranks are just lightly placed on the shouldered axle in this image. The backs will need thinning for frame clearance and, of course, crank pins fitted.  They will be a force fit, once quartered accurately.

 

It’s a excellent hobby that let’s you go from playing at being an artist to an engineer in the blink of an eye isn’t it?

 

Tim

[CF MRC]

Making this work will be a challenge.

Photos by Owen Chapman

It would be useful to have some dimensions for the valve gear, as these are going to be very critical. 

Tim

 

[t-b-g]

12 hours ago, CF MRC said:

Making this work will be a challenge.

Photos by Owen Chapman

It would be useful to have some dimensions for the valve gear, as these are going to be very critical. 

Tim

 

 

A walk in the park after some of the inside and outside valve gear you have done!

[CF MRC]

The chassis is now cut out: it will replace the front 2/3rds of the Heljan set up, but integrate with their fixings.  As ever, the two sides were sweated together, drilled and filed to shape. 

The frames are 1.5mm hard brass, with sighting rods in the axle holes in this picture. I am very lucky to have an incredibly accurate mill / drill and the chassis is pretty true. Various holes are for mounting the cylinders, motion support bracket and valve gear rocker.  The rebate at the rear will take the frame widened part of the Heljan chassis. 

One thing I have noticed was that the Heljan crank throw was about 0.5mm short. Can’t think why. 
 

Tim

[Phil Traxson]

On 21/05/2020 at 22:59, CF MRC said:

Making this work will be a challenge.

Photos by Owen Chapman

It would be useful to have some dimensions for the valve gear, as these are going to be very critical. 

Tim

 

I can assure you, being a volunteer in the works at the time, that making it all fit in and work on the real thing was not easy. Clearances were VERY tight and scale down to about zero on a model!! Unfortunately "Lyd" will now be stripped down for its second 10 year overhaul, as soon as the works are allowed to reopen, and so the opportunity to actually measure the gear in-situ will not occur for some time. How ever I'm sure Boston Lodge will have a drawing somewhere which they may be able to copy and supply ( again probably not until staff return) particularly if it is accompanied by a donation of " pictures of the Queen", which they are desperately in need of in the present circumstances.  

[CF MRC]

I now have all the necessary works drawings for the valve gear, thank you Phil. It will be fun...

 

Tim

[CF MRC]

The coupling rods were made from 1mm thick steel strip, two sweated together and then drilled 0.8mm on the mill drill. 
They were then roughly milled to shape. Sighting rods through the holes ensures that they are sitting level in the machine vice. 

The two rods were removed from the mill looking quite chunky. 

These were draw filed to shape together, again using the sighting rods to keep them in register. 

This photo shows one rod as filed roughly to shape and another completed with the inter-boss rod suitably reduced in thickness and the oiler corks filed into place.  The screw is 16BA for reference. That is the size of the bearing currently, but these will be running in brass bushes when complete. 

Final picture shows a rod sitting in front of the frames. 

The Heljan rods are quite close to scale dimensions, but don’t have the oil corks and boy are they sloppy!

 

Tim

Edited May 24, 2020 by CF MRC

[-missy-]

I'm so glad I have a CNC mill so I don't have to bother with all that faff anymore!

 

J.

[CF MRC]

I’ll stay as I am...

 

Tim

[CF MRC]

I started to mate the new chassis to the body substructure of the Heljan loco this evening. The design of this engine is really quite complex and it took a lot of head scratching to work out how to reverse engineer a new chassis into it.

The back end of the plastic frames were cut off and the cast fixing narrowed so that it fitted between the brass frames, with the plastic rearward extension on the outside. 

The cast internal engine weights have been on the milling machine having space made internally.  

This little gadget is very useful for measuring casting thicknesses https://www.ebay.co.uk/itm/DENTAL-WAX-TYPE-IWANSON-CROWN-CALIPER-TENTH-DIAMOND-GAUGE-ORTHODONTIC-MEASURING/282950014554?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200513093106%26meid%3D5a70b0e5081c4c869444d0e93ba405b0%26pid%3D100005%26rk%3D1%26rkt%3D12%26mehot%3Dpf%26sd%3D293274769253%26itm%3D282950014554%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithBBEV1Filter&_trksid=p2047675.c100005.m1851

The roughly put-together castings gives a clue as to why there is need for a bit more internal space. 

Tim

Edited May 26, 2020 by CF MRC

[CF MRC]

With the outside cranks and the somewhat complicated valve gear I thought it would be advisable to be able to drop the wheel sets.  To that end, the frames were dismantled and slots milled downwards.  The small vertical holes in the frames had been drilled already to take 16BA fixing bolts. 

The bottom half of the bearing and keeper was milled from two pieces of 1.5mm thick brass sweated together, with corresponding holes drilled for the fixing bolts.  As ever, working on both together saves a lot of time and is easier to file true. 

After adjustments the keepers can be seen trial fitted, but before the bearings were properly adjusted. 

The Heljan model has no representation of the brake gear and so the keeper was always intended to represent these.  However, in reality the rods are set back behind the frames. To achieve this effect, a rebate was milled down the outer and lower edges of each side of the keep. 

The bulk of the keep was the filed away close to the frames, but keeping representations of the brake hangers and, of course the bottom halves of the bearings.  It’s just roughly placed in this photo and will require further refinement and fitting for the axles. 

Quite a heavy evening’s work - the last time I made a chassis like this was for the Baldwin 2-6-0, back in 1982! Soon be time to get the chassis and wheels all assembled. 
 

Tim

 

[CF MRC]

The chassis has now been erected and wheels dropped in, at least for the front pair, as the rear axle is awaiting a gearbox and wheels: it is currently running as a little known MW jack shaft driven mechanism...

It all turns over nice and evenly by thumb power, even though it’s a bit stiff, as there is no slack anywhere.   The chunky 3D nature of the rods and the fly cranks just missing the frames shows up better in a 3/4 view. 

It will be interesting to see if the loco runs more steadily for using the outside bearings, compared to the more normal inside frames and bearings. 
 

Tim

[CF MRC]

The chassis has turned over under its own power today. The drive system is a Maxon 6V 6mm diameter motor with a 1:4 planetary gear box coupled to an 18:1 transfer box made originally by C & L. It is very narrow but needed some modification to the lower bearings and fixing bolts to make it narrower still.

Setting up the chassis, drive system and coupling rods was a bit tricky, but it has the major advantage of being small and tucked out of the way between the wheels.  The motor and transfer gear box will need a torque arm across the top which will also unify them and close up the gear box: this may well fix to the nearby cross member and give some stability to the set up. 

It all runs OK, but the frames need to be stiffened up and the axles need spacer washers to keep side play under control.  iPhones are really good at picking up gear & motor noise!

The back wheel (bottom left in the video) is due for replacement as it is eccentric, probably due to a small crack in the hub. 

Tim