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Scrap Tank Test Build – Part 6; Boiler and Running Plate

Now that the much of the bulk of the above running plate work has been completed, the running plate valences can be fitted.  As these are nearly always long and thin, they are prone to distortion in the kits I have built – so it is time for another jig!!  This one holds the valences at numerous places to stop it flexing and to hold it straight.

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With this, it is a doddle to fit the valences in their correct place and solder them without distortion.  I did find that the running plate flexed significantly at the end of the tanks; so the final version is going to include a pair of temporary stiffeners that fold down and stop this.  This would be the moment when they are removed to allow the valancing to take their place.

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And onto the boiler.  In a departure from normal practise, I am not including a flat etch to be rolled into a boiler – it is relatively difficult to get even a pre-rolled boiler into a neat tube without a visible seam and if you do not have a rolling machine it is effectively impossible to do so.  In addition, where boilers have been half etched to create boiler bands I find that the half etched elements that remain are overly delicate.  This was something that caught me out a while back when I drilled such and area to take handrail knobs and badly distorted the metal – this kit is still sitting in its box now and I am probably going to have to replace the boiler.

With these problems in mind, I simply used a piece of brass tube from Eileens; easier and much more durable and if I were sratch-building I would not even think of taking a different route.  This did still leave the need for some rolled parts, to make the smokebox and I have sought to use another little trick here to make these easier to fit – some tags and eyes.  The tags are strips of half etching that pass through the eyes and then tugged back.  This can’t impart a curve into the metal but does allow the parts to be pulled tight and makes it easier to solder into place without much of  lip.  Mind you, they were a tad short and will be lengthened slightly in the production run.

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A second additional laminate is then needed to form the outside of the smokebox and down onto the saddle.

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I did find another little error when it came to the front of the smokebox.  Whilst the diameter for the front that I had drawn had allowed for the thickness of the two laminates, when you fit these there is also a layer of solder between them and whilst this ought not be that thick, it was just enough to make the fronts too small.  In the production run, I will deliberately make this a tad too big as it is easy enough to file it back but much more difficult to add the missing metal (I didn’t, I just made a fresh one from sheet metal).  The smokebox door is not mine, the door from the Lochgorm Models Loch is the right size judging by the photographs (note the drawing in the old man’s book has it being smaller but this does not match the photos, so I ignored it in this respect – sorry Dad!).

The downside of using tube as a boiler is that boiler bands need to be considered.  I have provided these in the kit (again using the strap and eye technique).  I chose to fit them on this kit although in practise I think any metal boiler band is too thick and would probably have done it with a transfer sheet if this was not a test build (done prior to painting, the thickness of the transfer is enough to show through the paint on what will be a single colour to the boiler).

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Only the top of the boiler is visible after the first ring and a bit, so can be cut away to leave lots of room for the motor, weighting and DCC chip.  I may try and fit this with sound, so who can give a view on what it might have sounded like – a jinty is my favoured guess?

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Scrap Tank Test Build 5 – Getting on with the Chassis

With the basic chassis made, it is essential to fit the nuts to secure the body to the chassis as both of these will be concealed with later work.  So a quick test fit looks like this and we can get onto the next bit, the coupling rods. _DSC0361compress

As is not uncommon, these are made from a pair of layers of brass laminated together.  You can see that the outer layer is half etched for much of its length, with the full depth only being present at the bosses.  I have also sought to make it easier to build these by including them in a folding jig – the folding is underway in the bottom portion of the view. The logic of the jig, indeed the whole kit, is to make a really smoothly running chassis much easier to make.  Modern CAD and computer operated phototool creation techniques by the etchers means that it is possible to easily draw and then etch such that each dimension is faithfully repeated on the product.  Thus, it is possible to be confident that the wheelbase will be repeated exactly on each side of the frames and also on the coupling rods.  However, this accuracy is completely lost if the user has to laminate the two parts together by hand; it is not possible to get them superimposed on each other exactly or repetitively so the spacings of the crankpin holes will change.  The jig overcomes this as the fold line is so long that there can not be any twist as it folds, so the two parts will meet consistently and accurately. _DSC0271compress

It is true that there remain two areas of variability.  The first is that the degree of etching will not be exact on every occasion so the holes will be slightly bigger or smaller on each occasion.  This can be easily overcome by making all critical holes a tiny bit too small and then opening the holes up with a ream (not a file, reams will open up a hole consistently).  The second problem is that a fold is not always consistent on a fold line so the jig can protect against twisting but might not necessarily put the two laminates directly on top of each other.  However, the important point is is that they will be correct horizontally, any error can only crop up vertically.  Thus, when the crankpin whole is opened up, it is possible that it will move vertically slightly but this will not change the dimension between the holes so the critical dimensions should be retained perfectly.

The above is all true in theory but in practise there was an almighty cock up in my artwork; so I was deprived of finding out.  A total case of designer error and when this is yourself, there is no one else to blame………………. _DSC0276compress

………..I made one of the coupling rods no less than 8mm too long – doh!  I have no idea how, but it needed chopping; so it was back to the old fashioned way of making coupling rods despite my high ideals!  Fortunately, as they were laminated, it is possible to stagger the cut to make the splice – essentially the same technique as Alan Gibson’s variable length coupling rods. Anyway, after the cutting and splicing, I did get a sweetly running chassis and this is what it looks like.  The unusually large wheels for a shunting loco are already making their presence felt! Chassis 12compress Chassis 13compress

The chassis is created around CSB’s; continuous springy beams.  A spring wire is anchored to the chassis at four points per side (for an 0-6-0) and at the centre of each hornblock.  Thus each hornblock is supported on either side and can “bounce” on the spring.  However, the clever thing about CSBs is that when a hornblock is depressed, not only does the spring wire flex a bit as suspension, but it also rocks on the anchors so the adjacent wheels push downwards a bit to equalise out some of the deflection.  It produces a really smooth chassis and, if it is conceived at the design stage, I think is actually rather easier to both design and build than traditional compensation. This is a close up of a pair of hornblocks and a pair of the anchor points (the other is hiding behind the frame spacer on the right).  Also worthy of note is the colour coding of the hornblocks; to enable them to be reinstated in the same hornguide each time.  This is probably unnecessary with modern (and therefore consistent) hornblocks and the accuracy of the etching I have noted but old habits die hard! Chassis 16compress

Scrap Tank Test Build – Part 4; Beginning the Chassis

Putting aside the body for a while, to take a look at the chassis because it is necessary to mount the two together and it is not possible to close up some of the element of the body until this is sorted out.

As with the body, I am trying to take a moderately fresh approach to the chassis to make this a little easier to build than certainly most of the kits I am used to.  In this regard, most of the kits for the Highland are quite traditional in their design and I readily admit that all but two of my ideas has been either all out pinched from other designers or at least significantly inspired by them.  All I am trying to do is use more of these neat ideas in a single kit to make the life of the builder easier.  I am, however, finding that it makes my life more difficult, as there are a lot more moving parts to most components, so more places for the tolerances to be catered for; so as John Price has already said, the list of little tweeks and amendments to make is growing!  At least, no one can say this particular kit designer has not built their own model.

Anyway, this is what the chassis looks like in the flat; note that it is a fold up design – this is inspired by the Mousa Models chassis, so a pinched idea!

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And this is what it looks like with the basic folds made up.  What it achieves is really neat, as it is instantly sufficiently stiff to work as a chassis; by the time a couple of further cross braces have been installed the basic chassis is more than robust enough for its life.

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My design uses the same slide in hornblocks as utilised by Comet and Brassmasters for their chassis.  After a tiny bit of practise, it is possible to size the hole for the hornguides such that these are just too small when etched.  This means that with a few strokes of a light cut file on each side, the hornblock becomes a tight sliding fit.  Once all of the hornblocks are in, it is then possible to measure the distance between each on both sides of the chassis and also on the corresponding coupling rod.  This is done with digital callipers and by the expediency of measuring the distance at its maximum with the callipers facing outwards and then repeating with them facing inwards the average being the actual distance between the centres.  I reckon to be able to measure down to 2 or 3 hundredths of a mm, which is rather better than I can build to!  Where there are inconsistences, this is dealt with by a few more strokes of the file on the side which needs to be adjusted to change the centre.  This needs to be done anyway to turn the tight sliding fit to a snug but smooth fit for the hornblocks to work properly soif the centre does not need to be changed, the file strokes are undertaken equally on both sides of the hornguides.

This does need to be done after the coupling rods have been formed, of which we will see in the next posting.  However, the chassis is also designed with a keeper plate to accommodate all of the cosmetic springing to the model and the ashpan sides.  This is secured with a series of 12BA screws to enable it to be removed to allow the wheels/axles to be dropped out.  A great boon as the model is built and painted.

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To make the assembly of this element easier (in fact in this case a lot easier!) I have created a jig that holds the two layers of the laminate in exactly the right position.  The jig is chunky enough to avoid distortion as it is folded up and it locates the parts perfectly.  In this particular case, the soldering needs to be done with care as there are folds to make after the jig is cut away and it is important not to fill this with solder before hand.

And this is what the keeper plate looks like – it is pretty delicate until it is mounted but fine thereafter.

 

 

 

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And the two components assembled look like this.  The beginnings  of the cylinders are also visible, this is a slide in module that can be removed for assembly and painting (although the scrap tanks were painted fairly simply, so this is not really relevant on this model).

 

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Scrap Tank Test Build – Part 3; Cab Inner & Roof

I have designed the cab roof and much of the cab interior to be a separate assembly, that can be secured by a series of screws.  As can be seen below, there are two screws at the rear that locate into a tool box that sits on where the bunker projects into the rear of the cab.  As the screws are somewhat lost in the bunker, I have come up with a little dodge where these are retained by an initial nut that traps them in place but still allows them to twist and thus engage in the cab roof assembly.  The other screw comes through the top of the boiler, just inside the backhead.

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The roof is connected to these fixing points with some inner liners to the cabs which can be seen here; the nuts for the rear piece are hidden in the toolbox and to the front within the false top to the boiler.  You can just rebate in the rear spectacle plate that will take the glazing material.

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The actual cab roof has a double skin, to aid its strength, include the lamp irons and also to assist with locating it on the cab.  The outer skin includes the ribs that appear on the real roof, including a grove to allow brass wire to be used to form the seam to this.  To the perimeter of this, there is a valance.

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And this is what it looks like on.  I find that I just can’t make roofs sufficiently well to sit perfectly on the body and nothing shouts “its a model” more than gaps where there shouldn’t be any – be this under buildings, roofs or between parts that have to be joined to structurally stand up!  This is my solution, which I have used on other builds that I have done but it is so much easier when it is designed in.

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Early Pattern Lookouts for Dia 38 HR Goods Brake

I have been doing more with the Scrap Tank, but I haven’t managed to take any pictures due to needing flippers outside yesterday.  So instead, lets see something else that was on the test etch that I have recently had returned.

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This is the early style lookout for the dia 12 Highland Goods Brake.  As originally built these lookouts formed by a single slot to the centre of the roof and were fully glazed to the front and back.  In use guards complained that they caught their heads on the lip of the roof as they climbed in.  To overcome this, many of the vans were rebuilt to include ramped approaches to the centre of the lookout were incorporated, to become what was arguably the signature feature of the Highland’s rolling stock.

Microrail produced a kit for this van 30+ years ago and this included the latter style of lookout.  I had a pair of these kits and ended up acquiring a third one and I felt I really could not have another one just like the first two!  So I had an inspiration and thought it would be fun to make the early pattern lookout.  The old man’s book came out and a scan of the drawing loaded up into the CAD machine.  From here it was a relatively simple exercise to draw up the difficult bits, the glazed screens, and the more simple roof.

The components went together easily and do give a very different feel to the Microrail kit as intended.   I also made a number of other adjustments, to the footboards and also the panelling, to make the model both different and authentic.  The latter, the beaded panelling, is a right pain in the whatsit and took much longer than any other element of the assembly – so don’t to it unless really want to!  And this is what it looks like next to the kit as originally intended, with the later style lookout.

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I will be making these available via the Miscellany Models site shortly, when I have done enough of the other elements I am working on to do a production run.  In the meantime, I do have a pair of very slight seconds (there is a tiny bit of over etching – almost impossible to see, the pictures of my vehicle have the same problem).  These are available for the price of the metal; say £2.50, plus postage (which won’t be much).  Ordering is via here:  http://miscellanymodels.com

And the real thing looks like this:

HR.GBV4

(C) Bill Steel

Scrap Tank Test Build – Part 2; Continuing with the Body

The next stages of the test build were to do the footplate/tank sides/can exterior.

My initial design for the footplate is not particularly radical, but the test build has shown up that until the boiler is put in place (which comes some way into the build process) the front is somewhat delicate, irrespective of whether the footplate valences are fitted or not.  Thus, in addition to the temporary stiffener that can be seen to the front of the footplate in the picture below, stiffeners will be provided to the front half of the footplates.  The idea of these can be seen in the following view which shows the rear of the cab.  By folding these over at 90o during the build, they give strength to the more delicate parts of components.  Some will be incorporated into the finished article, others will simply be discarded when their job is done.

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The two tanks, along with the sides to the cab/bunker, are conceived as a single piece (if you go back to my previous posting, you can see this in the flat in the etch).  The two halves are separated by temporary spacers to both assist in locating them but also to give strength to the assembly prior to the fitting of the boiler which is where it will get its strength from.  It was when I tackled this part, I reached the first disaster – the etchers had failed to half etch from behind so I was missing some fold lines.  This was pretty frustrating as it entirely negated the intended efficiency of the  design and even though I now have a corrected etch, I had to solder on by cutting the parts at the intended line of the half etch and soldering them together in the more traditional manner – exactly what my design was intended to avoid.  As a result of this, there are no neat photos of the tanks being folded up and secured in place, we have to jump on a bit to see this.

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The cab fronts that were constructed earlier were no slid into place and I was pleased to find that it all fitted very snugly and in exactly the correct location.  I did find that I could put in a further pair of fold up tabs on the running plate that meant that it was essentially impossible to put this in the wrong location, so this is another little refinement that will make its way into the production batch.

The rear of the cab was a similar fold up unit to that to the front, which was pretty easy to build but did have one dimensional error at its base that needed cutting away – well that is the purpose of a test build!  All of this, has been created from one piece in maybe three minutes!

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And this is what it looks like with the cab rear in place.  If you look carefully, a couple of 12 BA screws are just visible in the cut out to the rear of the cab – the purpose of these will become apparent in a future posting but it is another one of my little ideas to make this easier to build/better when built.

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And this is what the cab bow looks like from above, after the addition of the splasher tops and backs.  One of the issues this illustrates is that this kit, as it stands, will only work for EM or P4 modellers.  There is insufficient room to get the narrower gauge/wider wheel treads into the splashers.

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Next up will be the cab roof………….

 

 

Scrap Tank Test Build – Part 1; Getting Started

I took the weekend off the other week and attended the Spring Railway Modeller’s Weekend at Missenden.  It is great to spend two full days just modelling away from the distractions of life and amongst people who are all doing exactly the same.  I find it a form of therapy and it is well worth going if you have been thinking about it (and even if you haven’t!).

I took with me the etches that I have had delivered by PPD for the Scrap Tank; with a view to doing a test build using them.  The origins of this class are some of the earliest locomotives built for the line; the Raigmore class.  In an attempt to increase the life of these new enlarged boilers were fitted to them.  Unfortunately for the Highland Railway the boilers were too heavy for their frames and consequently these cracked.  This left the Highland with a number of new boilers, wheels and many fittings but no locomotives!   Ever the frugal, they recycled these parts into a series of three shunting locomotives which were designed by Peter Drummond and these inevitably quickly picked up the name of Scrap Tanks.

These were rather brutish looking locomotives for the time, characterised by surprisingly large wheels for a shunting locomotive – something compelled on the Highland due to them reusing these from the Raigmore class which were mainline passenger locomotives with 5′ 3″ wheels.  For those of you who don’t know what these looked like, this is what we are aiming at:

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And this is what we are starting with:

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Whilst this may (well has!) got me into some trouble, I have sought to design the kit to be easier to build than the average etched brass kit and certainly easier than the Falcon Brass kits that are the staple in 4mm for many of the Highland’s locomotives.  I have sought to do this in a number of ways and the first area tackled, the cab front/interior, illustrates one of these; the use of fold up assemblies to assist not only in creating the shapes but also the laminations.  Many of the modern etch designers are using these (especially the 2mm boys/girls) but I have sought to do rather more than most (which has made the preciseness of the design rather more challenging, more of which anon).

The bulk of this assembly starts as a single piece, that is folded up to form the cab floor, splasher sides and the bulk of the cab front.  To assist the lamination process, jigs either side of the cab front have been used.  Wire rods are slipped through the small holes in these to ensure that they are registered on top of each other properly.

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The view below shows the laminations now sweated together and illustrates the square cut outs behind the cab front which are to enable glass/Perspex to be slotted in to represent the sceptical glazing.  The view also shows the boiler backhead which is made from three layers of etch (not with a folding jig – yet!).  I am pretty pleased with this as this is only 13 * 15mm in size, so the wheels on the backhead are only 2mm in diameter.

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To be continued…………(soon too!).

HR Cradle Bolster – First Test Build

I had a delivery from PPD a week back, so I have been playing with some test builds of this:

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This is a dia 25 cradle bolster; a type of vehicle that I have not seen on another railway.  It has a square cradle that sits on the top of this, with four bolsters protruding from the corners of the cradle.  They were used on pairs and the whole cradle rotated when the pair of vehicle went around curves.  The intention, I presume, was to offer the load more support by offering more points of contact.  Anyway, as no one else had tackled this vehicle before, I thought I would have a go!

As this is my first etched design for a vehicle, I have certainly encountered a number of problems.  As the top photograph shows I produced this in both 4mm and 7mm; the latter has proved more successful due to the thickness of metal being greater.  The main issue that I created for myself was to half etch the solebar overlays so that the rivets and the ironwork could be portrayed.  However, rather than backing them on a further layer of etch (like the etched kits I have built – they evidently knew something……), I spanned it between supports.  The intention had been to make the kit fold up more readily but in practise what has happened is that the half etched solebars have distorted (badly in the case of the 4mm one) due to the stresses introduced in the heat from soldering.  Thus, whilst I have a working model (at least in 7mm), a rework is going to be required.

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Both the 4mm and 7mm versions will have sprung axleboxes, using a varient of the guitar wire sprung version used by Bill Bedford and others.  The 7mm chaps don’t seem to use it much and I guess the mass of their models helps. However, it does glide with the springing and is better as a result I reckon.

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I have also done a 3-D design for the cradle, which I am proposing to use as a master for some resin castings (certainly in 7mm, I might go down the lost wax brass route in 4mm).  A new process that I have not previously attempted.  I need to find out where to get axleboxes and buffers from – Larrie Griffin I presume.

Also back from PPD, were some etches for something altogether more bold (which is a worry in the light of the problems I have encountered on a relatively simple wagon!).  This is the chassis and body etch for a Drummond Scrap Tank.  I have made a start on this and again, some reworking will be required but again there is a viable model in an amongst these parts; it just needs tweeking.  More to follow once I have got further with it.

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Benfieldside’s Signals – An Update

We have not had an update on the signals for Benfieldside for a bit. The first four of these, including the three that were restorations (although in respect of the twin doll signal, very little was reused indeed) are complete.  This is what they look like (with thanks to Phil Hall & the Scalefour Society for the pictures):

The three doll is a restoration from John H Wrights work, so too is the other in theory but the only components reused were the slated deck for the landing and the curved metal that formed the brackets!

The three doll is a restoration from John H Wrights work, so too is the other in theory but the only components reused were the slated deck for the landing and the curved metal that formed the brackets!

Gallows bracket to the right, restored from the John H Wright original.  The simple post signal is all mine!

Gallows bracket to the right, restored from the John H Wright original. The simple post signal is all mine!

The gubbins for operating these is not shown in the views and I will write up a bit more on this at some point but an article I wrote for Rail Express on the signals I did for Elcot Road can be found here.  A few of you may have played with these on the MERG stand at Scaleforum too, as I understnad it they kept people amused. There is more Benfieldside signal updates to follow, when I can get my camera out in the light to take some piccies.

A new website for Miscellany Models

I will be making at least some of the items that I have been developing available for sale.

Therefore, I have set up a separate website entitled Miscellany Models that shows what is available, how to get them and (when I get some time to do it) will become a repository for prototype information that I have on the items I have made, construction/finished photographs and instructions.

You can find this website here.  If you look hard, you will see some hints as to what other things I have been working on and are expected to be made available in due course.

Roger Farnworth

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