Banavie Road Coaches

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Banavie Road Coaches

Postby flubrush » Tue Mar 08, 2011 5:35 pm

Banavie Road will need some coaching stock and I wanted a rake of the Drummond four wheel suburban stock. In S scale that usually means scratchbuilding unless you can find an etch kit that you can get re-scaled and are willing to pay the price. :hmm: I had got original drawings from the NRM last year and had made my own drawings from them. So I reckoned to start scratchbuilding using Plastikard as I've done before, and using the late David Jenkinson's methods.

So I made a start - actually as a demonstrator on the S scale stand at Railwells last year. The results were not all that great but i never expect all that much on demo efforts since you are normally being distracted all the time, if not by members of the public at least by your fellow demonstrators. :) Later in the year I junked the Railwells efforts and started afresh, only to find that my efforts were still not very good. Maybe it's just advancing age, or maybe I'm just getting more pernickity in my old age, but the results didn't look all that good to me. So that put me in a bit of a quandary. I needed panelled stock on the layout - if not the wee Drummond four wheelers, at least some McIntosh bogie stock. Was I going to have to go down the etched brass road however I did it, or was there another way.

I just happen to have a CNC milling machine - got for another purpose - and I wondered about using that, I had heard that milling styrene was a no-no since the heat in the cutter started melting the styrene and making a mess of any cut. But I had picked up on the Internet that using carbide cutters got round this problem, so I did a bit more digging around on Google and came up with a contact in the G1MRA who had milled some freight sides from Plastikard. So I dug up his email address and we had a fruitful exchange of information and I set up to try out the method on panelled sides.

The Drummond stock has panelling on the lower sides of the body - rather like Gresley teak stock. So I decided to deal with a side as an upper and a lower part to cut down the milling required. I've been doing a fair bit of messing around, experimenting with various combinations of feed and speed with the cutters, and also working out the best way of setting up the project so that it takes the shortest time. My first attempt at complete set of coach sides would have taken well over twelve hours to complete - for a small 28' 6" coach. :) I'm now getting times down into the one to two hour bracket, but there is still a fair bit of expeimentation going on.

Here's a test that I did today - one side of a one compartment test coach side. ;)

milling03.jpg


The lower side fits on the lip on the bottom of the upper side. The rough edge on the right side of the drop light is where I have pushed things just a bit. I decided to incorporate a drop light at teh last moment and made it about five thou thick and at that thickness it looks as though the cutter has started picking at the edge and distorting it. It looks as though I will need to increase the thickness of the drop light by a thou or two to avoid this. However, the rest looks good - certainly a lot better than my earlier manual attempts.

Here's the setup

milling01.jpg


The mill is a Seig KX1 and it is controlled by Mach 3 software on a pretty basic PC running WinXP. The work table on the mill is a piece of Contiboard bolted onto the table to give a smooth surface for double sided tape.

milling02.jpg


A closer shot of the milling head with the 1mm diameter cutter at work, These cutters are a bit fragile hence the experimentation to find feed and speed settings which don't break the cutter. :)

I'll now set up to do a full set of sides - two of each of the upper parts and the lower parts.

Jim.
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Re: Banavie Road Coaches

Postby iak » Tue Mar 08, 2011 7:53 pm

WOW...
Now that is stunning in concept and the execution is nae bad either 8-)
Is this a glimpse of the future for some modellers?
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Re: Banavie Road Coaches

Postby Clive » Tue Mar 08, 2011 8:53 pm

Hi Jim

Taking commissions? It looks an excellent way of doing panelled coaches.

Clive
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Re: Banavie Road Coaches

Postby flubrush » Tue Mar 08, 2011 9:25 pm

Clive wrote:Hi Jim

Taking commissions? It looks an excellent way of doing panelled coaches.


At the moment it's not a quick way - at least not until I find out how fast I can drive the cutters and the Plastikard. :) There are also restrictions - the main one being that I can't do square cornered panels or windows. With Midland style square panelling, I wouldn't use the mill, but do it using the more traditional methods and with microstrip for panelling. For coaches from companies like the G&SWR, where the top of windows were rounded and the bottoms were square, then a milling cutter will always leave a radius which wouldn't be right for such coaches.

With a bit more experience I might take commisions. :)

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Tue Mar 08, 2011 9:33 pm

iak wrote:WOW...
Now that is stunning in concept and the execution is nae bad either 8-)
Is this a glimpse of the future for some modellers?


I must admit that I was quite surprised that the surface finish was so smooth in the panels. I expected some form of tooling marks - as you often get when milling metal. Laser milling/engraving might well be a better way of doing such things since, for instance, you can do square corners with a laser. What I would like to do with this setup is more complex work - like the cab ends of a Blue Train - that's if I can ever find a good drawing of a Class 303 to work from. :)

Jim.
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Re: Banavie Road Coaches

Postby Cock Sparra » Wed Mar 09, 2011 9:41 am

Hi Jim

Could you not do the drop lights separately as per most etched kits, that way you could add some in the open position.
Cheers Phil

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Re: Banavie Road Coaches

Postby flubrush » Wed Mar 09, 2011 10:59 am

Cock Sparra wrote:Could you not do the drop lights separately as per most etched kits, that way you could add some in the open position.


That's what I originally intended to do with the test, but decided to add the drop light in to see how it looked. If I incorporate the drop light as shown it means that the glazing can be one strip for the whole side. With separate drop lights I would have to have separate pieces of glazing for drop lights and quarter lights. On these Caledonian coaches the glazing in the quarter lights and the drop light was , as near as dammit, on the same plane according to the cross section of the body side on the plans. So I reckon that including the drop lights in the main body part will give a good representation of glazing depths. I agree that on other types of coach, there should be a noticeable difference in the depth of glazing on the various lights and that separate drop lights would be preferable to achieve this.

If I want some open ones, I might have to reach for the craft knife and do something by hand. ;) ;)

Jim.
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Re: Banavie Road Coaches

Postby Cock Sparra » Wed Mar 09, 2011 4:41 pm

Hi Jim

I currently have a pair of Clifton Down auto coach kits in 4mm on the stocks from Roxey Mouldings in etched brass and having soldered some of the drop lights on in the open position, whilst the sides are still flat, I have offered up the plastic glazing I drew round the inside of the open window with a marker pen and then cut out the openings which probably took about 5mins or less per aperture including fettling to get the glazing behind the etches.

When I have progressed beyond some of the stumbling blocks that I have encountered building these kits I intend to do a series of postings on the building of these kits, but so far I have not made sufficient progress to make it worthwhile.
Cheers Phil

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Re: Banavie Road Coaches

Postby flubrush » Fri Mar 11, 2011 7:48 pm

Just a bit further down the road and milling the full side for the four compartment first coach.

milling04.jpg


This is the 2mm diameter mill on the run to cut out the panelling level, and also to cut through the sheet to the finished size. There are a lot of small bits of Plastikard about. :D I sweep them off the cutting surface with a stiffish paintbrush.

And now the finished sides with the top two held together with the tape, and the bottom two separate.

Coachside01.jpg


Apologies for not cleaning them off properly. I thought I had but just noticed the odd bits as I was composing this message. :)

It took just over 3 1/2 hours to cut this out, so it is not a quick operation. I could do it quicker since I am still being conservative with feeds and speeds and some accidental experience I've had has shown that the cutters can do a bit more (forgetting to zero the 1.5mm cutter and finding that it could cut through 30 thou Plastikard, plus the plastic surface of the Contiboard and a bit of the chipboard underneath, and not break :D :D )

I've left off the droplights. I had another go at trying to reproduce them slightly thicker, and that didn't work so I'm going to give in gracefully and add them later. :)

I'll move on and do the brake third and the five compartment third now.

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Sat Mar 19, 2011 7:20 pm

A week passes and what have I got to show - well a few more sides and some ends.

coachsides01.jpg


At the top are four sides for the four compartment first coaches. The Caledonian normally ran these coaches in rakes of five with an all first in the middle which was sandwiched between two all thirds then there was a brake third at each end. I want to make two rakes, so I've got my full complement of all first sides. :)

Below is one side of a brake third. I'm still experimenting with this coach to work out how I will build it to incorporate the large birdcage style end to the brake.

Below that are two all third sides with the matching lower panelled sides. I will use these to build the first trial coach since the all third sides are the weakest with a large amount of hole space in them. If I can get the coach constructed to hold these sides flat and square, then the other coaches should be OK. These all third sides have been flattened. When I release the sides from the double sided tape, they take up a curl as a result of the peeling action I have to use. I have had a trial at flattening them and it has worked very well. I clamp the sides between two bits of flat alloy strip (from B&Q) using spring clothes pegs, and pop the lot in the oven at 100C for about ten to fifteen minutes, and they come out nice and flat. I could use boiling water which would probably be a fair bit quicker but the oven is easy. :)

At the bottom is one brake end and a couple of ordinary coach ends. The other part next to the brake end is a former to help construct the brake end with its duckets. On reflection, I should have cut the two forward facing ducket windows on this former.

It doesn't seem a lot for quite a busy time working on them. But I'm finding out about CNC as i go and I've hit a few mini brick walls on the way. :) And I also have sympathy with etched kit designers, with having to work out how things fit together. :)

Jim.
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Re: Banavie Road Coaches

Postby iak » Sun Mar 20, 2011 10:23 pm

This gets more fascinating all the time and its Caley which is even better ;)
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Re: Banavie Road Coaches

Postby flubrush » Sat May 28, 2011 7:32 pm

Just an update since I've been doing a fair bit of experimenting over the past month or so. The picture below shows some of the work.

coachsides02.jpg


At the top are some North british four wheeled coach sides for another member of the S Scale Society. This coach is very similar to my Caledonian ones - maybe both being designed by Drummond might be a clue. ;) Below them are a pair of two compartment testers from Caledonian 45 foot bogie coach drawings. This experiment is my first attempt at producing bolections on the quarter light window frames and I have had limited success so far. I have to do a bit more experimenting with tool feed rates to get the contours I want, It needs a lot of hand coding in Gcode to do this with the software I've got at the moment, so experimenting takes a fair bit of time.

At the bottom are two 3mm scale sides for the Caledonian first coach. I thought I might see how things look in the smaller scales and I had cutters which were small enough in diameter to allow me to go down to 3mm scale. I might try 2mm scale but the only problem is that the cost of the cutters goes up exponentially as the size gets very small. :)

I'll be on the S scale stand at Railex tomorrow, Sunday, supposedly demonstrating, :) and I'll have all my bits and pieces with me, so pop by if you want to see the sides "in the flesh".

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Thu Jun 02, 2011 8:18 pm

As you might have seen in the previous message, I had started trying to reproduce bolections which was quite a noticeable feature of many panelled coaches. David Jenkinson had a method which looked fairly easy but which I didn't find easy when I tried it. I had several attempts trying to develop other methods to produce a good result - like heat moulding thin plastic rod to go round the window to be the bolection protrusion and trying to emulate the sloping inner side of the bolection by having a slightly smaller frame in the window opening and filling between the plastic rod and the backing with intentionally thick paint to form a sloping shape. It did work after a fashion, but it took forever to do. So I was determined that I would form bolections with the CNC machine.

I started of with a small sampler of two compartments. These were based on the McIntosh 45ft bogie stock and had the later, simpler style of panelling to the Drummond four wheeled stock. When I do the basic panelling on the coaches, I use 2D methods and software. The additional information added is the depth of a cut or an area to the 2D information. This machine code from this method machines quite quickly, especially if I change cutters to get the optimum size and feed rate during the job. To do a 3D object like a bolection moulding requires that I use 3D software. Technically I could do the whole coach side in 3D but that could take many hours to do and I decided to mix 2D and 3D to get the shortest time for the process.

The first job was to cut the basic panelling and window openings using the 2D software. At the end of the process, the side looked like this....

coachsides05.jpg


The waste material in the openings has been left in, held in place by a very thin layer of Plastikard. I could cut right through but that could mean the cutter damaging the face of my very expensive holding mat and as a Scot, I can't allow that. ;) ;) So I aim to leave about one thou at the bottom of openings to act as a safety barrier. I also make sure that the 30 thou Plastikard is there or thereabouts in thickness. Try measuring the thickness of styrene sheets with a vernier or a micrometer - you can find a wide variation in thickness - sometimes on one sheet. :o

Around the quarter light I have machined a rectangular section with the 2D software which will be the base material for the bolection. I then start cutting that section with the 3D code and produce the bolection moulding around each window. Here is an oblique close up of one of the compartments - also showing the droplight frame cut in place - as another experiment.

coachsides03.jpg


And now a broadside shot of the complete side.

coachsides04.jpg


Apologies for not cleaning the part up completely. You don't see all these small rags and hairs until you blow the pictures up to much more than life size :) But I'm happy with the result. The first attempt last week did not look all that good - the bolection hardly protruded at all from the panelled surface. But I had a session with the machine at the start of this week and found out about backlash which had been flattening the section. I found out that I am able to apply backlash compensation, which I did, and the result is what I had hoped for. In fact I might look at reducing the protrusion since it might be a bit too much. It scales to 3/8" in S scale.

The next move is to write some software that might speed up the 3D work in the way that the section is cut. I'll let the commercial software do all the hard work with the co-ordinate geometry, then I'll take the results and modify the machining paths. Good fun :D :D

Jim.
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Re: Banavie Road Coaches

Postby Clive » Thu Jun 02, 2011 10:05 pm

Mind blowing work. Well done.
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Re: Banavie Road Coaches

Postby flubrush » Tue Jul 05, 2011 9:01 pm

Nothing world shattering to report but just to say that I am still plugging along with the milling machine - tending to feel like a dinosaur with all these Shapeways threads on the go. :D

But the work over the past month has been more of the "what can I get away with" empirical work. To date I have concentrated on some sides and ends for a fellow S Scale modeller and in working out how they would all go together - i.e. sides and ends to full width and length and with internal chamfers on the joins, or sides inside ends with the width of the ends reduced to accommodate the sides. I am now starting to sympathise with etched kit designers. :D

Here's the work so far on one coach - a four wheel Drummond NBR Brake Third

NBR_Brake-x.jpg


The sides extend to the duckets and butt up against the inner ducket former. The two parts of the ducket panelling join the inner ducket former to the brake end. The main problem area was juggling with styrene thicknesses around the brake end side windows. This is a "Beta Test" to see if things will go together fairly easily, but I expect that there might be some alterations in the brake end area. The problem is the internal construction of the coach which can become obvious through these large rear windows. This is also a proving ground for my Drummond Caledonian four wheelers which are fully glazed across the end and will show even more of the guts. :D

Jim
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Re: Banavie Road Coaches

Postby Richard Oldfield » Thu Jul 07, 2011 2:37 pm

Hi Jim,

Superb work :D

The thinness of the ducket ends is striking - how does it survive the milling process without distortion?

Cheers,

Richard
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Re: Banavie Road Coaches

Postby flubrush » Fri Jul 08, 2011 6:21 am

Richard Oldfield wrote:The thinness of the ducket ends is striking - how does it survive the milling process without distortion?


That was the cause of a lot of the experimentation. :) I had to arrange when I did the cutout operation to avoid problems around that area. Previously the order of cutting parts had been based on cutter size, starting with the large sizes and working down to the smallest sizes. But I had to eschew this method and find out an order of cutting which suited the parts. Also, when I am cutting I do it in several passes with each size of cutter - at most 10 thou at a time, so material is fairly well supported during the cutting process until the final break through pass and then the forces are not too strong when cutting the fairly thin remaining section. The question remaining is whether we can assemble these ends successfully. :) I'll now do my Caledonian brake ends and see if I have any success - what I need is CNC assembly. :)

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Fri Jul 22, 2011 1:14 pm

Just a word of warning to anyone who might be contemplating using the Seklema Multimat - its thickness is not all that constant.

I've just had a fairly exasperating week working on the coach sides. I had initially started off referencing the cutter height to the top surface of the styrene sheet and that had given me some problems with the variations in thickness that you can get with styrene. Last week I decided to alter my methods and reference all the cutter heights from the base of the styrene. Then I could use a thicker sheet and surface cut it to the thickness required, then do all the milling of the panelling. This method should have guaranteed that all the depths of cuts should be correct, but on the various attempts and tests I had done, they were anything but that. I tended to start looking at the CNC setup for the problem. The software sends data out to the mill and expects it to follow the data accurately. There is no form of positional feedback from the machine to the software (except for limit switches) so it is possible for the mill to do something different to what is intended. So I've spend days with a dial gauge, a micrometer and digital calipers trying to tie down what was or wasn't happening. I never even thought about the Multimat. I had checked the table under the Multimat and it was about two thou out along its length. That was as close as I could get the Contiboard to being flat and I had accepted that.

However, I thought I might just check the Multimat. It's not easy to measure directly because its surface is resilient, so I laid a steel rule on it and set the dial gauge on the rule's surface, and found that I had a 15 thou variation in six inches. At last I had my reasons for the errors. I had been setting tool height at the edge of the Multimat with a piece of metal of a known thickness then the tool was moving further into the centre of the material, and the Multimat, to start the cutting.

I also checked the unused bit of Multimat with the calipers and that shows similar amounts of difference around the edges. I have never seen a tolerance for the thickness of the Multimat. I had assumed wrongly that it would be quite tight in tolerance since it was intended for engraving where cutting depths are quite small and variations in material thickness would become quite obvious. I might be able to query the manufacturer via their web site to see what they say.

In the mean time, I'm back to looking at low tack double sided tape and I've googled a few suppliers so will get a roll of that to see how it does.

Just in case anyone else was looking at purchasing Multimat (at £65 /sq.ft :shock: ) and expecting constant thickness.

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Sat Aug 27, 2011 3:49 pm

There has been some progress. :D :D

After the problems with the Multimat, I did a search around to see if there was anything else which might be suitable and eventually came upon Letraset Low Tack double sided tape. I find this tape to be really good and almost as good in operation as the Multimat. It is reckoned to be re-usable but on a milling machine table with all the swarf around, it's easier to use a new bit than try and clean of a previously used bit.

I've also changed my modus operandi. Previously I had referenced all my cut depths to the top surface of the Plastikard and, with the variations in styrene sheet thickness, this was giving me problems with depths of cuts. I discovered that my CAM program would also work by referencing the bottom of the material, so I now use that method and I now start off with a sheet that is slightly too thick and surface cut to the maximum thickness required then cut to all my other thicknesses. This has now brought an element of predictability to the process, and piles of white swarf. :D

I've now cut all the sides I need for two rakes of five coaches and I thought it about time to actually start putting some together. Because my quarterlight glazing will be at a different plane to the droplight glazing I had to give a bit of thought on how I could hold the glazing in place. I like my glazing removable to make painting a bit easier so I had to work out some way of doing that with the David Jenkinson construction method. Eventually I decided on milling a thick inner coach side with the levels to suit the coach side shape and with slots to hold the glazing material - in my case 10 thou Plastiglaze. Here's a pic of two inner sides of the four compartment first followed by a closer shot of the slots for one compartment.

coachsides08.jpg


coachsides09.jpg


These are cut from 80 thou Plastikard and the small square holes in the lower sides are for ventilation. The quarterlight slots are 12 thou deep to give a bit of clearance for the 10 thou glazing and the droplight slots ate 22 thou deep to give clearance for the glazing plus the 10 thou droplight frame.

Before sticking the outer sides to these parts I formed the curved lower tumblehome sections of the outer sides in the oven. I had machined a male mould in alloy some time ago and I fitted a couple of clamps to hold the sides in shape. The next pic shows the mould with the clamps released and the following one shows the mould with a side clamped in it before being put in the oven. The sides are "cooked" for about ten minutes at 100C but at that temperature I've left a side in the oven for a bit more than ten minutes and it survived with no apparent over-cooking damage.

coachsides06.jpg


coachsides07.jpg


Putting the two parts together wasn't too difficult. The inner sides were machined shorter to allow for 20 thou thick ends and the main concern was to line the sides laterally so that there was an equal 20 thou difference at each end. Holding the sides vertically with the toolmakers' clamps meant that the bottoms of both sides could be lined up easily.

coachsides10.jpg


I used the minimum amounts of Mekpak to join the sides - basically along the top and bottom seams and a small dab in the bottom of each droplight slot. I don't like getting too much Mekpak around Plastikard - too much can have longer term knock-ons. :o
I had cut out a pile of droplight frames from 10 thou Plastikard

coachsides11.jpg


and one of these was stuck to the glazing material to make up the droplight, and the glazing for the two quarterlights was cut, then the lot inserted in one compartment to see how it looked.

coachsides12.jpg


I've only half inserted the left hand droplight glazing. Apologies for the rather dirty glazing material - since it was only a trial I wasn't taking too much care in how I handled it. :D I'm happy with the end result and, of course, I can have droplights in open positions as well if I want.

On a parallel course, I've done the artwork for a nickel silver etch of sprung "W" irons for the coaches and I might see the results back from PPD in the coming week.

I've also just been milling the ends for the coaches as I write this, so I will form a couple of them and see if I can get a body together fairly soon.

Jim.
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Re: Banavie Road Coaches

Postby brian_bnss » Mon Apr 23, 2012 6:54 pm

Hi Jim,
That's some macine you have there, I'm sure you could make all your brass parts with that, see attached link

http://heekscnc.blogspot.co.uk/2008/08/sieg-kx1.html

All the best,

Brian.
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Re: Banavie Road Coaches

Postby flubrush » Tue Apr 24, 2012 9:04 am

brian_bnss wrote:That's some macine you have there, I'm sure you could make all your brass parts with that, see attached link

http://heekscnc.blogspot.co.uk/2008/08/sieg-kx1.html.


Brian,

Many thanks for that URL. I haven't had a chance to dig through all of his blog but it looks as though he has done, or is doing, a lot of GCode programming which might give me a few pointers to what I want to do. I have some specific requirements which can only be met by purchasing expensive CAM software - £1000+ - or doing the coding myself, which is not an easy undertaking when the grey cells are getting a bit old and past it. :D

I have cut metal with the KX1 and I intend to use it for items like my loco frames, etc. I've also used the machine just to clean up parts accurately - like my brass coach solebars which I cut to just over length by hand from brass strip, then finish off in the mill to exact length, and a lot squarer than I could probably file. :D

It has been a bit remiss of me not to post any more recently and Ill add some more bits and piece after this.

Jim.
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Re: Banavie Road Coaches

Postby flubrush » Tue Apr 24, 2012 9:26 am

Back in January, I picked up on the Caledonian coaches again. I last worked on them in September when I used a trial underframe for one as a test bed for sprung axleguards for an article in the S scale Gazette. Just previous to that, I had had another go at making an arc roof to fit on the bodies. I had made one a month or two earlier and used the laminate method with thin Plastikard sheet but it had not been a success. With this second attempt, I reckoned to let the roof season for some months so that I know that it would not distort after time, and so far it has stayed the way it was built. I still used the laminate method, but just two sheets of thicker material rather than four sheets of thinner material. Here's the roof on the first class coach which is perched (not too squarely!!) on the trial underframe.

coachsides14.jpg


However, the real elephant in the room was the construction of the birdcage style brake ends on the brake thirds. I had also done some sides for a fellow S scale modeller who is building the NBR versions of Drummond's design and we had an exchange of ideas as to how we could achieve a good result. It was he who came up with the idea of a Perspex inner structure to stick the Plastikard sides to which would also act as the glazing. So I started with a go at a frame using 2mm Perspex sheet.

coachsides15.jpg


The front and rear frames are in the middle with the spacers to the right. I re-cut the Plastikard sides for the test.

The Perspex bits made up into the former like so

coachsides16.jpg


However, I let my fellow S scale modeller see this picture and we both reckoned that the two vertical spacers would be visible through the windows so it was back to the drawing board to change to one vertical spacer.

coachsides17.jpg


With the new parts in the foreground which made up into this

coachsides18.jpg


with its "two former" predecessor in the background. I glued the Perspex with Butanone - my 35 year old MekPak wouldn't look at it. I then tried a test assembly with the sides with varied degrees of success.

coachsides19.jpg


The ducket sides are supposed to fit between the ends such that the thickness of the end pieces becomes the end panelling on the sides. This worked quite well on the upper panelling, but getting the compound curves correct on the lower rear edges was a bit of a fight and I'm going to have another think about improving that. I had also developed the 2D sides to account for the S curve of the duckets and over-cooked it such that they were about 0.75mm too long - hence the untidy tops and bottoms. I also got one glue stain on the windows but that was just due to a bit of clumsiness on my part. The Butanone wicked nicely under the Plastikard and didn't intrude into the glazing area. If I can't get brown or dark Plastikard, then I will have to find some way of disguising the inner side since it sticks out like a sore thumb when viewed through the rear windows. :)

Jim.
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Re: Banavie Road Coaches

Postby iak » Tue Apr 24, 2012 9:46 am

WOW :shock:
They look the business Jim... :drool
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But I may choose to serve perfection....
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Re: Banavie Road Coaches

Postby flubrush » Sun Apr 29, 2012 3:51 pm

Well, in between getting used to a new(to me) dog - a Staffie cross rescue case - and getting the February S Scale Gazette out, I managed to have another look at these brake ends and thought I would try using much the same method as I have used for the coach sides with a Jenkinson style Plastikard inner support with cutouts for glazing. What follows is, I think, the third attempt since I got into a right mess with various versions of files and differing measurements that I went back to the beginning and started all over again.

An issue I have with DraftSight, which I have been using, is that is does not update a file's date and time stamp when you re-save it after alterations. I got into the habit of searching for files by date from my previous profession of digital sound handling, where the date and time stamp of a file could be the fastest way of finding it. So I was picking up wrong versions of DraftSight files - and there were a lot - so I'm now back onto AutoCAD LT which does update file date and time stamps.

The inner frames were cut in a similar fashion to the perspex ones, with the same style of spacers. Here's the complete set with the outer sides on the left, the inner sides in the middle with the spacers, and the ducket sides on the right.

coachsides20.jpg


The inner parts have rebates milled for the glazing material - 12 thou deep in this case for 10 thou clear acrylic sheet.

coachsides21.jpg


The inner frame was built up.

coachsides23.jpg


And the inner outer face (IYSWIM) is stuck on. The ducket sides are designed to fit in between the sides, with the edges of the sides reproducing the edge panelling on the duckets, so the inner side has to project 0.35mm to achieve this.

coachsides24.jpg


And the ducket side fitted

coachsides25.jpg


You can just see about a one thou ridge on the left side and it is about the same on the right side (although it looks worse). I will wait until it has all hardened and then do a bit of light sanding to smooth things down.

I'm happy with the lower side with the complex curve. Here the edge of the outer body side should be flush with the body with the lower panelling on the ducket side protruding. The join is well disguised by the panelling and I'm pleased with it.

coachsides26.jpg


And the final part is the glazing. I cleaned the slot out with a strip of 10 thou phosphor bronze which I keep handy for these kinds of jobs, then slipped the 10 thou glazing in.

coachsides28.jpg


All that is left now is to trim off the glazing.

So it has worked out quite well and it will be a bit easier to deal with the interior as far as what can be seen through these large windows. The system will also work with the NB coaches I have also been milling for another fellow S scale modeller. I will go with this method for the four brake coaches, although proving the method with the perspex frame could be very useful experience for future models with difficult glazing requirements.

Jim.
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