Building an MTK 4-DD Double Decker

[74009]

Thank you for all your comments - didn't think this would create so much interest.

 

So, today I went down the road of no return and cut one of the etches along its length.  I used tin snips for this but the brass tried to deform on both sides of the cut, so for the next one I'll try a saw, or maybe a slitting disc.

 

I measured out where the first rainstrip will be (about 2mm above the top window line) and scored a fairly heavy line along the bodysides at this point.  I then cut the etch in half down the middle of the roof, then continued to cut bits off until I was as close to the line as I dared get; with all the distortion going on this was about 4mm.  I then used a file to get down to the line - a very long and arduous process with such thick, hard material.

 

The cutting process generated large numbers of very sharp shards of brass, from the large to the very small, and these managed to get, and stick in, everywhere.  I was reminded of the time some years ago when I couldn't sleep so I got up and, wearing only a dressing gown, used a fibre glass pen to clean and burnish some metal parts.

 

Below is the beginnings of the result - the side I started working on yesterday held in the bending bars (with an extra g-clamp in the middle) and the other side basically still flat.  You can also see the selection of tools that was used.

 

 

Edited April 23, 2022 by 74009

[74009]

This is the current situation for the first side - I'm actually reasonably happy with it and it does seem like this method is going to work.

[74009]

The sides do have a tendency to bow slightly from end to end, but trying to permanently straighten them sometimes leads to a sudden kink in one of the thinnest areas, usually above one of the big upstairs windows.  However the bowing is very minor, and there's going to be plenty of room to solder a flat brass bar along the insides if necessary.

 

Looking at the ends, I said yesterday that I thought they looked a bit on the tall side.  I haven't measured them but, comparing with some pictures of the real thing, I think in fact they're about the right height but a bit narrow, which is why they look tall.  I compared them with the ends of an MTK 'Tin HAL' I have here and it's very clear that Colin used the same master, but with the tumblehome cut off at the sides and some extra material added at the top.

 

I think what I might do is get a pair of 4SUB ends from the No Nonsense Kits range and alter them to fit - this will mean changing the headcode detail and adding material at the top, but there's no detail at all up there so hopefully not too hard.  This will also help with the width as I can file whatever's required off the sides of the SUB casting then fill whatever gaps are left.

 

Edited May 9, 2020 by 74009
Grammar

[Darius43]

Great work so far - this literally is kitbashing.

 

Cheers

 

Darius

[74009]

Thanks Darius.

 

Another advantage of doing it this way which has just occurred to me is that I can drill all the holes for the door handles and grab rails while the pieces are still in the flat. I could even scribe the insides and do them from the back, to avoid the danger of the drill slipping and marking the outside.

 

Cutting out and shaping all the sides is going to be a long process but the advantages seem, so far, to outweigh the disadvantages.

 

Incidentally, this is going to be in BR Blue.

 

Cheers

 

Stuart

Edited May 9, 2020 by 74009

[dasatcopthorne]

You've done really well re-shaping that side!

 

Dave Smith

Elbow LaneDCC

[Doncaster]

On 08/05/2020 at 17:20, 74009 said:

 

 

Hi Mike

 

Yes I'm not sure what happened with the MARC models one.   Some years ago MARC models actually borrowed the very kit I'm building now - I think they were interested in looking at the area around the guards van doors.  They must have made some progress because when it came back one of the coaches had a couple of brass coach ends soldered in, which weren't part of the MTK kit. I do think their kit was advertised for sale for a while but I never saw one.

 

Best regards

 

Stuart

Hi Guys,

I enquired about the MARC Models 4-DD a couple of years back.  I was told it was available only as ready to run because of the problems in shaping the one piece body/roof etch.  Apparently there was a press tool made for this specific purpose.

Shame really.  I used to travel on 4001/2 regularly as a schoolboy (Ex Charing Cross,  1634 from London Bridge to Dartford via Bexleyheath).

Cheers,

Vernon

[74009]

4 hours ago, dasatcopthorne said:

You've done really well re-shaping that side!

 

Dave Smith

Elbow LaneDCC

 

Thanks Dave.

 

Trouble is I nearly destroyed my thumbs in the process - I actually think I'll only be able to tackle one every third day or so unless I can find a different method  

[dasatcopthorne]

Can you borrow rolling bars off anyone?

 

Dave

[74009]

11 hours ago, dasatcopthorne said:

Can you borrow rolling bars off anyone?

 

Dave

 

Hi Dave,

 

I do have some rolling bars - they're only about 10cm long but it's still perfectly possible to bend a full length coach with them. (You can see them in the first picture on this page).  I had been using thumb pressure on the bars to bend the brass but I had to push with all my weight and that, in combination with continually tightening and loosening the wing nuts on the bending bars, had started to get pretty uncomfortable.

 

Last night, for the second side, I decided to try using a hammer on the rolling bars.  Care is required but it works a treat, so that's what I'll do with all the other sides.  It was reasonably easy to match the profile with the first side too. No more pics yet - and I'm having a night off tonight.

 

Best regards

 

Stuart

[hayfield]

Stuart

 

Its called panel beating !! I watch things like the Repair shop and various of those car rebuild programs and am amazed at how craftsmen can mould a sheet of metal 

[wainwright1]

On 08/05/2020 at 13:15, 74009 said:

I've had this kit for some 20 years and I've occasionally opened it up, had a think about it and packed it all away again, but I've decided that now is the time to just get on and do it - if it fails that's probably no worse than it laying unbuilt in a box.

 

Stuart

 

Hi Stuart.

You are lucky to have one of these kits, I think that only a handful of them were produced.

On 08/05/2020 at 18:42, Darius43 said:

I also have the Engine Works resin 4-DD kit somewhere.  I have built a few resin coaches - they start out ok after completion but over time go banana-shaped, which is somewhat discouraging.

 

I think it has an interior, however, so I will see if I can find it and take some photos, which may be of use.

I have one of those resin kits as well. Again I think only a limited number were made and each one had a certificate.

The trouble with these is that they started out banana shaped, though from memory it is not from distortion, I think that the mouldings are much deeper at the ends and they droop in the middle. I think that if some car filler were put inside the cab ceilings there would be enough meat in the ends to perhaps rub the roofs down on a sheet of fine sandpaper or wet and dry laid on a sheet of plate glass or similar to gradually re-shape them to the correct profile.

They did include internal detail, although a lot it was twisted or out of correct alignment with the sides. However, it  would give the approximate details for a more accurate model.

There was an article in the Railway Modeller many years ago where someone had scratch-built a 4DD which included scale drawings. He had commissioned whitemetal castings from ABS including the unique bogie sides and I was able to contact him a few years ago. Unfortunately, he no longer had the masters for the castings. 

I know someone else who has one of these MTK kits and someone else who I think has two of the resin ones.

Happy modelling. I look forward to seeing the results.

 

All the best and stay well.

Ray

[74009]

Hi all,

 

Thank you for your continued interest and support.

 

Only a quick update tonight.  I finished filing down the second side to size - this was much, much quicker than the first side - I think the file must have been almost completely blunt compared to the one I used today.  I then did a bit more 'light fettling' with the rolling bars and the big hammer.

 

I think I mentioned early on that I wanted to get the profiles of the 4 coaches the same; by using the rolling bars it was actually quite easy to get a close match.  At this stage that's all I'm aiming for - once all 8 sides are cut out and roughly shaped, I'll spend more time on getting them as uniform and blemish free as I can.

 

[74009]

Something that has been very helpful and is no more than blind luck is that the set of bending bars I have is pretty much exactly the same width as the distance between the solebars and the start of the curve - so I can still get the shaped sides in there and give them a good hammering to make them as flat as possible where they should be.

 

That's it for tonight - time for some telly.

 

Stuart

[74009]

I mentioned in an earlier post that MARC models had borrowed this kit a few years back, and when it came back to me one of the coaches had a couple of brass ends soldered in.  Below is an image of what they are like.  

 

I also mentioned that I reckoned the MTK ends were too narrow, which is why they look too tall.  I've done some measuring up now and the MTK ends are 32½ mm wide (8' 1½") and the MARC ones are 35mm wide (8' 9") so quite an appreciable difference.  According to Blood & Custard the actual width at waist level is 9' 0" so the MARC ones are considerably closer and presumably they were intended to be soldered inside their body shells, which would make them spot on.  Unfortunately I only have 2 so I either can use them as a template to make 4 more, or I can widen the MTK ones with microstrip.  I'll wait to see what I'm dealing with when the body sides are ready and I move on to that stage.

 

Hi all,

 

 

Edited April 23, 2022 by 74009
Grammar

[74009]

In fact the flat part of the body sides taper just very slightly and are wider at the bottom than at the top.  It's not much though and in many photographs isn't noticeable at all but I think you can see it in the top picture here:

 

https://www.bloodandcustard.com/BR-4DD.html

 

 

[74009]

So, further progress has been made and all 4 bodyshells are now split into 2 pieces.  I did the second one with tin snips, but there was an incident during this process last night which left me within a whisker of needing a trip to A&E. Fortunately that was avoided and all seems well today.

 

All of the sides need further cutting then filing back to the rainstrip line, followed by work on the profile, so there's probably not going to be much to report on until that's all done.  I'm hoping that by then the No Nonsense 4-SUB ends will have arrived and I can experiment with them to see if they can be made suitable.

 

Sharp jagged edges after using the tin snips - they could easily do someone a mischief

 

 

Edited April 23, 2022 by 74009

[74009]

Hi all,

 

In the end I decided to use a Dremel to cut the remaining bodyshells up.  Whilst I have an intense dislike of high speed spinning blades, it did do the job quickly and neatly; I laid a strip of masking tape down as a marker and guided it by hand.

 

The result is sufficiently close to the line that I'll be able to finish them all off with a flat file - hopefully it won't take too long now that I've discovered that the file I used for the first side was blunt, and I do also have a sharp one.

 

 

 

Edited April 23, 2022 by 74009

[74009]

The next stage will be working out how the curve needs to be so that it neatly abuts a roof section; I do have a plan for this involving some strips of small H section brass. If I solder the flat edge of these just under the top of the curve using solder paint, I can clamp it really tight in the bending bars and heat with a flame - this will encourage the tops of the curves to stay flat and it will also give me the rebate of the 'H' to slide some formers into to put the roof section on top of. Hope that makes sense,

 

I also need to be able to set the width between the sides so that I can size up the roof and the ends to fit.  What I'm thinking about here is to accurately cut a few blocks of wood to go inside as templates, then I can clamp the sides to those with more strips of wood on the outside, held with screws going through the window apertures.

 

So, a day or so's filing awaits, followed by the panel beating to the final shape.

 

Stuart

Edited May 28, 2020 by 74009

[MJI]

Very interesting project.

 

I'd go for brass inside ends and solder them for strength.

[74009]

On 29/05/2020 at 16:14, MJI said:

Very interesting project.

 

I'd go for brass inside ends and solder them for strength.

 

Yes I think you're right Martin.  I'm just looking at the ends now - a once only chance do decide on width, height and profile.  I found a very handy picture taken directly head on with pretty much no perspective distortion - it's the third picture from the top here:

 

https://www.kentrail.org.uk/Bulleid_4DD.htm

 

You can just make out from the painted details on the end that the max width is 9' 3" - I've seen conflicting info on this but that is one of the quoted dimensions.  What I'm trying to find out at the moment is how much the bodysides taper inwards towards the top - by measuring from that image, if it's 9'3" at the bottom then it's 9'1½" at the bottom of the cab windows, 9'0½" by the top of the cab windows and 9' exactly where the curve into the roof starts.

 

If anyone has any info on this I'd be very grateful if you could share it.

 

Best regards,

 

Stuart

 

Edited May 30, 2020 by 74009

[Hal Nail]

Hi,

 

You can probably estimate the impact of distortion as the route indicator window appears to taper slightly, which I assume is perspective rather than it actually narrowing?

 

So if, say, it appears to taper 2% overall but the route indicator tapers 0.5% due to perspective, then the real taper is at most 1.5%.

 

I think that works!

 

Ian

Edited May 31, 2020 by Hal Nail

[74009]

Hi Ian,

 

Thank you for that suggestion - in fact that's exactly what I did

 

When enlarged though, the route indicator window seems to be a pretty much a pixel perfect rectangle, almost no tapering at all - so whatever perspective distortion there is must be very tiny. I suppose though that the tapering will become more pronounced the further away you get from the camera height. 

 

I used the Perspective Correction Tool in Photoshop to bring the very top of the roof forward just a tiny bit and I think I'm pretty much there.  I don't really want to post the images on here directly as they have a copyright marker, but below is the headcode panel with a rectangular box drawn round it.

 

So now I just need to make 10 of those in brass - one for each inner end and four to represent the guard's van walls, as this will help to make the actual front end nice and rigid for fitting the cab front to.

 

Overall this is quite an involved job - but for a rare kit of a unique prototype I think it's worth moving along slowly and getting everything as right as I can.

 

 

All the best

 

Stuart 

 

 

Edited April 23, 2022 by 74009

[74009]

Hi all,

 

Sorry for the lack of updates - I've got a couple of other projects running concurrently, which are the repair and restoration of a 25-year old MJT 4VEP and a pair of refurbished Clacton Units which are built from Worsley Works sides, 3D printed ends and Replica coach bodies.  Both of these projects are nearing completion and getting them off the workbench will allow me to concentrate on the 4DD afterwards.  I will put a couple of threads up about those too.

 

For the 4DD I have decided on a final profile that I'm going to use for the coach ends, and below is the template (made from the photograph referred to 4 posts above.)  So I need to use this to cut the ends out of brass sheet first, then use them to determine the final bending of the sides.

 

It could be a while before I post again as I do want to get the VEP and 309s off to their new owners - but the 4DD project will continue straight after those

 

Stuart

 

Edited April 23, 2022 by 74009

[74009]

Hi all,

 

Time for a question.

 

Having decided on the profile in the pic above, I was sent by the 4DD preservation group a diagram which shows the body being 9' wide and with absolutely vertical sides, no tapering whatsoever.

 

Does anyone know for sure?  I can convince myself either way depending on which diagrams / pictures I look at.

 

On the data panel painted on the end of the units it says 9' 3" - presumably though this would include grab rails, which are excluded from the dimension on the diagram and could easily account for 1 1/2" each side.

 

The MARC models ends were parallel sided too.

 

I mentioned earlier that I had to get a VEP and a 309 done before I could return to this project - the VEP is done now (thread below) so I just need to get the 309, which is ready for painting, off my bench and it'll be back to the DD.

 

If I haven't found any more information by then I'm going to go with the diagram, 9' 0" wide and no tapering.

 

All the best,

 

Stuart.

 

 

Edited August 5, 2020 by 74009