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2mm Coal Tank test build

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Some months ago, I contacted John Redrup of London Road Models to enquire about the possibility of him producing a set of 2mm etches of LRM's Coal Tank kit. There was sufficient interest within the 2mm community and from elsewhere to make this a goer in terms of numbers and last week the first batch of etches arrived.

 

It's by no means a full kit but there are enough parts available commercially to build the body save that the boiler on the 4mm kits is a resin casting. We've been lucky though that Mike Bryant's son, Alex, found the master that Mike did for a boiler casting together with a couple of whitemetal castings so having got my hands on the etches I'm now putting together a test build of the body etch to see what, if an, alterations are required to make another master and get some more boilers cast. If that doesn't work, 3D printing might be an option, but a metal boiler's going to add some much needed weight.

 

Chris Higgs has also kindly agreed to do a specific 2mm chassis and work is in hand on that at the moment, but I thought it might be a good idea to open a thread to record the build and lessons learned and if anybody else who's building one wants to chip in that's great.

 

Whilst the initial batch of etches and more are all spoken for, more are being ordered, so if anybody's interested and hasn't contacted me already then please drop me a PM.

 

Right ... let's get this show on the road.

 

First off, the etches as supplied by LRM ...

 

IMG_2171_1024_zpspt0nt6t0.jpg

 

... and then the first stage of the build - tank trunks added to the running plate ...

 

IMG_2173_1024_zpsu41z99jb.jpg

 

IMG_2175_1024_zps9kakt0mb.jpg

 

Initial issues:

 

  • the slots from the 4mm kit haven't etched very well and need opening up;
  • the slots for the valances on the underside of the running plate are too close to the edge to open up sufficiently to accept the valances, so they'll have to be replaced by 0.8mm brass angle; and
  • depending on how Chris designs the chassis etch the running plate is going to have to be isolated from the chassis to facilitate split frame construction.

 

I think this could be something of a challenge!

 

Regards,

 

David Varley

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Some months ago, I contacted John Redrup of London Road Models to enquire about the possibility of him producing a set of 2mm etches of LRM's Coal Tank kit. There was sufficient interest within the 2mm community and from elsewhere to make this a goer in terms of numbers and last week the first batch of etches arrived.

 

It's by no means a full kit but there are enough parts available commercially to build the body save that the boiler on the 4mm kits is a resin casting. We've been lucky though that Mike Bryant's son, Alex, found the master that Mike did for a boiler casting together with a couple of whitemetal castings so having got my hands on the etches I'm now putting together a test build of the body etch to see what, if an, alterations are required to make another master and get some more boilers cast. If that doesn't work, 3D printing might be an option, but a metal boiler's going to add some much needed weight.

 

Chris Higgs has also kindly agreed to do a specific 2mm chassis and work is in hand on that at the moment, but I thought it might be a good idea to open a thread to record the build and lessons learned and if anybody else who's building one wants to chip in that's great.

 

Whilst the initial batch of etches and more are all spoken for, more are being ordered, so if anybody's interested and hasn't contacted me already then please drop me a PM.

 

Right ... let's get this show on the road.

 

First off, the etches as supplied by LRM ...

 

IMG_2171_1024_zpspt0nt6t0.jpg

 

... and then the first stage of the build - tank trunks added to the running plate ...

 

IMG_2173_1024_zpsu41z99jb.jpg

 

IMG_2175_1024_zps9kakt0mb.jpg

 

Initial issues:

 

  • the slots from the 4mm kit haven't etched very well and need opening up;
  • the slots for the valances on the underside of the running plate are too close to the edge to open up sufficiently to accept the valances, so they'll have to be replaced by 0.8mm brass angle; and
  • depending on how Chris designs the chassis etch the running plate is going to have to be isolated from the chassis to facilitate split frame construction.

 

I think this could be something of a challenge!

 

Regards,

 

David Varley

 

So some quick bits of info for people who haven't built etched kits before.

 

Slots that under-etch are quite common. Bob Jones told me a couple of tips for this

 

1. Make some mini-chisels from the etch waste itself to open slots out. These can be filed to various shapes and pushed through the slots. They are exactly the rght thickness you need to make the slots!

2. Sometimes it's easier to file the tabs smaller (or removed altogether) than to make the slots larger.

 

I am thinking of putting a replacement footplate on the chassis etch as the shot down 4mm versions seems to have stubbornly large bits of solid metal about where the drive gears are going to go. 4mm modellers have it easy in that they can put their gearboxes and motors more or less where they like and have plenty of space left over.

 

Chris

Edited by Chris Higgs
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"•the slots from the 4mm kit haven't etched very well and need opening up"

 

To be honest I would prefer this to them being over size, I have had the oversize problem on  couple of 7mm scale kits and it can lead to a sloppy build.

You have to decide which side of the slot to fit things, which has implication later in the build and everything can gradually get of line and not fit.

 

I find running a small broach along the etched slot works or even a small drill/mill bit (various small diameter PCB milling bits can be bought on ebay for a very reasonable price).

 

Looking forward to the kit, I am hoping to get a 7mm one to build soon as well!

 

Argos

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Re under etched slots, I have had success on other kits with thin strips of fine wet and dry pulled back and forth through the slot.

 

Andrew

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Slots that under-etch are quite common. Bob Jones told me a couple of tips for this

 

1. Make some mini-chisels from the etch waste itself to open slots out. These can be filed to various shapes and pushed through the slots. They are exactly the rght thickness you need to make the slots!

2. Sometimes it's easier to file the tabs smaller (or removed altogether) than to make the slots larger.

On my etches i make the tabs slightly tapered at the ends and slightly chamfering the long edges of them with a file can help too.   The etching process is not an exact science, so there is always the potential for under or over etching between sheets etched at different times.  As Agros has said, under etched holes and slots can be opened out, there is nothing you can do about over etched ones.

 

Jim.

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In the case of the slots for the tank trunks I ended up using a combination of Chris/Bob Jones suggestion of using a small triangular piece of etch (though I had to thin it), the smallest broach I've got (0.46mm) and a very fine piercing saw blade, and even then I had to thin the tabs but I got there in the end.

 

I'm also now considering buying a set of Tamiya's etched 0.1mm saws as it was a struggle.

 

A note on the tank trunks by the way. These represent the tunnel connections between the side tanks and the bunker tank and whilst they're the correct height for the Coal Tanks as originally built, the connections were replaced in the 1920s by a flexible pipe which had a lower cover topped off with a piece of chequer-plate, so if you're building a post 1920s loco you might want to replace the etched parts with some square tubing or rod of the appropriate size.

 

Which reminds me ... I'd thoroughly recommend trying to get hold of a copy of 'Bashers, Gadgets and Mourners - The Life and Times of the LNWR Coal Tanks' by Peter Skellon - lots of photos, general arrangement drawings and detailed drawings of various bits and pieces - £19 for 256 pages - http://ingrowlocomuseum.com/?page_id=35

 

Regards,

 

David.

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A little bit more done this evening - coal bunker door and toolbox doors soldered to the inside of the back of the cab. Alignment was a little bit tricky and with hindsight I should have marked a line to make sure all the doors were level - messed up with the coal bunker door which is a bit wonky, but hopefully you won't be able to see that once the cab's assembled and resorted to a piece of wood secured by Blu-Tack to line up the toolbox doors.

 

IMG_2176_1024_zpsvhwedt1l.jpg

 

The toolbox doors are another feature that's time dependent, as the positions of the toolboxes was modified at least twice. Originally, the toolboxes were mounted on each side of the coal bunker with access via a lid which hinged inwards towards the engine, but during the 1890s the toolboxes were raised and moved outwards, though still with inward opening lids. in 1904, instructions were issued for the toolboxes to be turned so that the lids opened outwards and for chains to be fixed to the lids to stop them falling back and fouling the loading gauge, but later the same year further modifications were carried out with the lids of the boxes being riveted shut, one end being removed, and the boxes being moved forward to butt up against the rear of the cab with doors being provided so that access could be gained from inside the cab, with coal rails being added to the rear of the coal bunker.

 

The toolboxes for the 4mm kit are whitemetal castings so either you'll need to fabricate your own or N Brass Locos have some in their range. 

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Hi David,

 

What is the distance between the outer edges of the slots in the footplate for the driving wheels and splashers?

 

Nig H

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Hi David,

 

What is the distance between the outer edges of the slots in the footplate for the driving wheels and splashers?

 

Nig H

 

Hi Nigel,

 

12mm give or take a gnat's whisker.

 

David

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Steady progress today - cab window surrounds soldered to the rear spectacle plate and the bunker sides and rear spectacle plate folded up and soldered to the running plate. In addition, I've also added the frame for the rear of the bunker door to the rear spectacle plate (this isn't something that's on the etch but when you look at photos, it's quite a prominent feature (see http://www.warwickshirerailways.com/lms/lnwrhr64.htmfor a good shot). I suppose you could go for a very well coaled engine to hide it but I thought I'd have a go a representing it using phospher bronze strip which I now need to thin down a bit (would probably have been better using wire). It needs to be cut short at the bottom so as not to foul the top of the bunker but a gap there can easily be hidden by coal and the toolboxes.

 

in one of my previous posts I mentioned that I was thinking about buying some Tamiya 0.1 saws and having done so they're proving very helpful in opening out slots and removing the parts from the etch.

 

A few more thoughts on the build so far:

  • I've decided to use window surrounds with protective bars (as fitted by the LMS) but there are some plain plain surrounds on the etch for anybody building an LNWR/early LMS loco.
  • The holes in the 'ears' of the bunker top for the cab step handrails have hardly etched at all so will require careful drilling (I used a 0.3mm drill in a pin chuck).
  • The 'slots' through which the 'ears' of the bunker top fit need opening out to accept them but be careful you don't go too far with them.

Progress shots below.

 

Regards,

 

David

 

IMG_2180_1024_zpsgkkhieqt.jpg

 

IMG_2181_1024_zpshaa7kwou.jpg

 

IMG_2183_1024_zpsid23nzc1.jpg

 

IMG_2184_1024_zpsnxbqfglp.jpg

Edited by Branwell
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A question for those following along if I may ...

 

Having added the rear of the bunker, comes the realisation that once the bunker top goes on, there's going to be quite a bit of empty space (about 900 cubic mm if my maths is correct) that it might be sensible to put some weight into. But, not knowing at this stage how heavy the completed loco's going to be and where else I'll be able to add weight (boiler and sidetanks seem the obvious locations) is this something that I should be leaving until I've got more of the build done?

 

Thanks,

 

David

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A question for those following along if I may ...

 

Having added the rear of the bunker, comes the realisation that once the bunker top goes on, there's going to be quite a bit of empty space (about 900 cubic mm if my maths is correct) that it might be sensible to put some weight into. But, not knowing at this stage how heavy the completed loco's going to be and where else I'll be able to add weight (boiler and sidetanks seem the obvious locations) is this something that I should be leaving until I've got more of the build done?

 

 

In general I would say that you can't have too much weight in a 2mm scale loco, especially a small tank loco, from the point of view of getting adequate traction.  All my locos lose traction before the motor stalls.    However, you have to keep the centre of gravity over the driving wheels.  If you can get enough weight in the tanks and boiler to balance that in the bunker, then there shouldn't be a problem in an 0-6-2T.  0-4-4T's are another matter!!  One other thing to bear in mind is that the bunker is a useful place to put a DCC chip, should you decide to go that way now or in the future.

 

Jim

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To give you an idea of how counter-productive weight in the wrong place can be, I once built a (4mm scale) 0-4-0ST that was ever so, ever so slightly nose heavy. All we're talking bout here is a CofG three or four millimetres in front of ideal, yet running bunker first it would wheelspin when running light engine while forwards it could haul eight BR Mk1's up a 1-in-100 gradient without a hint of slip - which was considerably more than the prototype could.

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Here is a 3D mock-up for my chassis design. Now I just have to wait for the etches that turn this in reality.

 

Chrispost-1605-0-71364300-1453656538.pngpost-1605-0-51089300-1453656567.png

Edited by Chris Higgs

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Now I just have to wait for the etches that turn this in reality.

 

They were posted on Friday Chris, so should be with you shortly.

 

David

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More progress today:

 

Back of bunker soldered in place ...

 

IMG_2189_1024_zps6wmpjejp.jpg

 

IMG_2190_1024_zpse6s701zb.jpg

 

... cab window surrounds soldered to front spectacle plate ...

 

IMG_2191_1024_zpsnddkjyjj.jpg

 

... side tanks folded up and soldered ready for fixing to the running plate ...

 

IMG_2193_1024_zpsrugvlwon.jpg

 

... and soldered in place ...

 

IMG_2196_1024_zpsp4gtgthn.jpg

 

IMG_2195_1024_zpsafwqja6l.jpg

 

IMG_2201_1024_zpszgniwfgj.jpg

 

IMG_2199_1024_zpsgqci1n6f.jpg

 

... and finally for now, with Mike Bryant's master for the cast boiler loosely positioned between the side tanks to check for fit - goes in quite snugly!

 

IMG_2205_1024_zpsyx8zblj6.jpg

 

Have decided to leave the weight question for now - see how a straight build ends up first.

 

Regards,

 

David

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They were posted on Friday Chris, so should be with you shortly.

 

David

 

No, I meant my new chassis ones. Doing 3D items and sending to Shapeways is now a lot faster.

 

Although I could try the frames in the etch LRM have done onto this block. Hmm....

 

Before you go too far in your test build you might want to note from the chassis images where you are going to need to cut extra holes in the footplate around the rear driving axle.

 

Chris

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No, I meant my new chassis ones. Doing 3D items and sending to Shapeways is now a lot faster.

 

Although I could try the frames in the etch LRM have done onto this block. Hmm....

 

Before you go too far in your test build you might want to note from the chassis images where you are going to need to cut extra holes in the footplate around the rear driving axle.

 

Chris

 

Sorry Chris, thought you meant the LRM etches :fool:

 

Think I'm just going to do a straight build for the first one - see how everything goes together - and then go from there.

 

David

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From about 1928 a number of the locos were fitted with vacuum controlled regulator gear for motor trains. There is an excellent photograph of the equipment, fitted on the right hand side of the smokebox, on page 110 in 'Bashers, Gadgets and Mourners'. Whilst there are some diagrams of how the system works the book doesn't seem to have any drawings of the gear. Prior to this it seems that they had rod operated control gear.

However, as part of a short series on LMS auto trains, Railway Modeller for August 1964 has dimensioned drawings, produced by Bill Ibbot of the LMS Society, of the vacuum equipment. The article by Bob Essery concerns the building of a model of 7700 from the K's kit that was available at the time.

 

David

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Not quite so much progress today, despite having a day off work - blood tests (part of my annual MOT) and food shopping had to take priority! Also bought the latest MRJ and got thoroughly distracted :)

 

Had a bit of a battle fitting the cab floor - had to file back the front edge to clear the slot for the front spectacle plate and trim the sides of the floor edge to butt up against the tank trunks and even then it was tricky getting it in place and soldering it - ended up skewering it with a pair of tweezers, slotting it into place and then holding the whole lot (running plate and all) upright with the tweezers whilst I applied flux and solder and then a quick in and out with the iron to tack solder the floor edge before soldering the cab sides to the rear of the side tanks.

 

Having done that it was onto drilling handrail holes in the tank tops but then I realised that, pending a delivery from Eileen's, I'm out of 0.3mm wire so that's probably as far as I'll get until that arrives, though having done a trail fit of the tank tops and the front spectacle plate more fettling's going to be required as the spectacle plate's now sitting too high with the result that the tab isn't locating into the slot. Might be a case of a bit of angle to sit it against but then need to look at whether that's going to leave with a backwards sloping cab roof!

 

Cab floor in place ...

 

IMG_2207_1024_zpsss5ucxim.jpg

 

Side on view showing the cut back side plates

 

IMG_2208_1024_zpsrovoexkn.jpg

 

Tank tops with handrail holes drilled to 0.3mm (guide holes haven't etched so drilling was preceded by a gentle tap with a centre punch)

 

IMG_2210_1024_zpsaeelulud.jpg

 

Thinking about the cab floor, from what Chris has said, it may well be that it's going to be in the way of the the drive gears so will have to be omitted and/or further modified but I've made the decision to do this build following the 4mm instructions and then, having learnt how the etches are supposed to go together, doing another build to fit Chris' chassis etch.

 

I'm also going to have to take the short stroll down to the Worth Valley and try and get an shot of the real thing from above - there's only one decent elevated shot in Bashers, Gadgets and Mourners (on the SLS Abergavenny - Merthyr last day special at Brynmawr) but it's from a distance and at an angle rather than looking straight down. Haworth station footbridge here I come!

 

Regards,

 

David

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More work on the body yesterday - coal bunker lid soldered in place and rear cab step handrails, toolboxes and coal rails added. The toolboxes are N Brass Loco castings and both they had and the coal rails had to be ever so slightly shortened for a good fit.

 

IMG_2212_1024_zpsziajajzk.jpg

 

IMG_2213_1024_zpsolqyr0qe.jpg

 

IMG_2216_1024_zpsmkc8s4kh.jpg

 

Regards,

 

David

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Guest bri.s

As a newby to 2mm kit building it's great to see these walk throughs,they're invaluable for someone hoping to do an etch loco kit in the future

 

Great work

 

Brian

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Not quite so much progress today, despite having a day off work - blood tests (part of my annual MOT) and food shopping had to take priority! Also bought the latest MRJ and got thoroughly distracted :)

 

Had a bit of a battle fitting the cab floor - had to file back the front edge to clear the slot for the front spectacle plate and trim the sides of the floor edge to butt up against the tank trunks and even then it was tricky getting it in place and soldering it - ended up skewering it with a pair of tweezers, slotting it into place and then holding the whole lot (running plate and all) upright with the tweezers whilst I applied flux and solder and then a quick in and out with the iron to tack solder the floor edge before soldering the cab sides to the rear of the side tanks.

 

Having done that it was onto drilling handrail holes in the tank tops but then I realised that, pending a delivery from Eileen's, I'm out of 0.3mm wire so that's probably as far as I'll get until that arrives, though having done a trail fit of the tank tops and the front spectacle plate more fettling's going to be required as the spectacle plate's now sitting too high with the result that the tab isn't locating into the slot. Might be a case of a bit of angle to sit it against but then need to look at whether that's going to leave with a backwards sloping cab roof!

 

 

 

Thinking about the cab floor, from what Chris has said, it may well be that it's going to be in the way of the the drive gears so will have to be omitted and/or further modified but I've made the decision to do this build following the 4mm instructions and then, having learnt how the etches are supposed to go together, doing another build to fit Chris' chassis etch.

 

 

 

Regards,

 

David

Hi David,

 

Concerning the footplate and room for the gears, I'd usually put a hole in the footplate after I had completed all the building work because you have a stronger structure to hack/ grind away at. If you put the hole in the footplate before you've added the superstructure you might find the footplate is quite weak and easily bent whilst cleaning up etc. So, I think you've done the right thing in completing the body first. I reckon that it won't take long to grind a hole in the footplate with a slitting disk in a minidrill. If that is all that is required to get the body over the gears, then I would have thought the footplate included in the LRM etch would suffice, rather than go to the trouble of etching a custom 2mm version.

 

I too am following this topic with interest and looking forward to getting my etch.

 

Nig H

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Hi David,

 

Concerning the footplate and room for the gears, I'd usually put a hole in the footplate after I had completed all the building work because you have a stronger structure to hack/ grind away at. If you put the hole in the footplate before you've added the superstructure you might find the footplate is quite weak and easily bent whilst cleaning up etc. So, I think you've done the right thing in completing the body first. I reckon that it won't take long to grind a hole in the footplate with a slitting disk in a minidrill. If that is all that is required to get the body over the gears, then I would have thought the footplate included in the LRM etch would suffice, rather than go to the trouble of etching a custom 2mm version.

 

I too am following this topic with interest and looking forward to getting my etch.

 

Nig H

 

Hi Nigel,

 

I've always preferred building the body before the chassis - as you say it becomes easier to fettle plus if you start making modifications to the chassis before trial fitting the body, how do you know you're not making a monumental cock up?

 

I think Chris is doing his chassis etch anyway, but I'm going to have a go at the LRM chassis when I've finished the body - see what I can make of it and all good practice!

 

David

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