Building an MMP RMB - a box of delights

3 LINK

Western Thunderer
Oh, please do! I have an MMP BCK stashed under the bed that I'm dying to make a start on, but I simply don't have the time or space available to get cracking. :-(


Regards

Dan

I'm afraid Time is the one major thing you will need Dan, although that time would be enjoyable. :thumbs:

Regards,

Martyn.
 

SteadyRed

Western Thunderer
I think once we have followed Heather build this MMP kit we will all start building MMP coaching stock.

Mmm special offer...

Dave
 

Heather Kay

Western Thunderer
Okay, stand by! Announcement imminent!

I have cut metal. I repeat, I have cut metal!

There's something about the first cut that I find hard. I spend ages thinking about things before I make the effort. I don't know whether this is because I'm afraid of making a mess of things right off the bat, or it's just a big step to cut an etched work of art. Anyway, I've started.

The instructions begin with constructing the bogies. I'm skipping that, because I already have bogies for this model, so the first component out of the etch is the main underframe web. You have to remove some sub-frets first, and some platform areas not required for this type of coach, and then you can remove the web itself (part 1).

IMG_7466.jpg

I've formed the buffer beams, but you can see this fret is very flexible - and vulnerable - at this stage. I very carefully cleaned off the tags with a pair of those snazzy sharp scissors, sharp knife and careful filing. No matter how careful I was, one or two tiny creases happened. Hopefully they won't affect things as I go.

IMG_7467.jpg

The first parts for the cross trusses (4 off part 2) at the bogie pivot have been trimmed out and cleaned up. For those four parts, I have referred to the text instructions and drawings several times to understand that these parts are fitted a specific way round. At first glance, they're identical. Careful examination reveals half-etched lines on each side which indicate how they should be fitted to the underframe.

There are some more parts to cut out and prep at this stage, but I've decided the excitement of actually cutting out the first few parts and making two folds was sufficient for today. I think some proper soldering will happen tomorrow.
 

3 LINK

Western Thunderer
Okay, stand by! Announcement imminent!

I have cut metal. I repeat, I have cut metal!

There's something about the first cut that I find hard. I spend ages thinking about things before I make the effort. I don't know whether this is because I'm afraid of making a mess of things right off the bat, or it's just a big step to cut an etched work of art. Anyway, I've started.


Morning Heather,

It's good to know it is not just me then, with me it's that feeling of not wanting to spoil the lovely shiny frets :rolleyes:.

I have built the MMP 08, and I can honestly say the attention to detail is unrivalled in my opinion, and the etches and folding sequences are a work of art.

Regards,

Martyn.

P.S. David, just put the fiver in the post ;).
 

Heather Kay

Western Thunderer
Progress is slow, but steady. I find I can be a slow starter sometimes.

I've been warned to keep an eye on alignments, especially with the cross trusses and subsequent longitudinal framework. I had become aware of the likelihood of problems arising when fixing the first cross member to the main frame web. The following is not meant as criticism, more as highlighting things for other builders.

What is not obvious from the drawings is the cross truss does not stretch the complete way across the floor web. There's a little under a millimetre of free space at each end. The critical thing is to ensure the slots align properly with the half-etch line that runs the length of the web. If misalignment creeps in, distortion and twisting might occur later, which would be the very devil to correct.

IMG_7468.jpg

The most obvious thing is to cut out the long truss etch and use to help keep alignment. As a quick alternative, I used one of the cross trusses I had yet to fit - later replaced with a length of scrap etch. This helped me to align the second truss with the first, and with the web.

IMG_7470.jpg

Even now, there's a tiny bit of misalignment that's crept in, because the slots and half-etch still have to be aligned by eye at some stage. I hope, being aware this has happened, I can make sure it doesn't get any worse as the build progresses.

IMG_7471.jpg

Even though I've only fitted eight components so far, the web is already beginning to become stiffer. As the remaining cross trusses go in, I suspect things will get much firmer.

(I can't help it. My inner Kenneth Williams is making noises and sniggering about double entendres. :D )

As I said, I'm a slow starter. The first bogie pivot section took me ages. The second one was a lot quicker to fabricate. I hope things will swing along nicely with the rest of the truss work tomorrow, but this afternoon I am switching attention to 57xx.
 

djparkins

Western Thunderer
Progress is slow, but steady. I find I can be a slow starter sometimes.

I've been warned to keep an eye on alignments, especially with the cross trusses and subsequent longitudinal framework. I had become aware of the likelihood of problems arising when fixing the first cross member to the main frame web. The following is not meant as criticism, more as highlighting things for other builders.

What is not obvious from the drawings is the cross truss does not stretch the complete way across the floor web. There's a little under a millimetre of free space at each end. The critical thing is to ensure the slots align properly with the half-etch line that runs the length of the web. If misalignment creeps in, distortion and twisting might occur later, which would be the very devil to correct.

View attachment 28085

The most obvious thing is to cut out the long truss etch and use to help keep alignment. As a quick alternative, I used one of the cross trusses I had yet to fit - later replaced with a length of scrap etch. This helped me to align the second truss with the first, and with the web.

View attachment 28086

Even now, there's a tiny bit of misalignment that's crept in, because the slots and half-etch still have to be aligned by eye at some stage. I hope, being aware this has happened, I can make sure it doesn't get any worse as the build progresses.

View attachment 28084

Even though I've only fitted eight components so far, the web is already beginning to become stiffer. As the remaining cross trusses go in, I suspect things will get much firmer.

(I can't help it. My inner Kenneth Williams is making noises and sniggering about double entendres. :D )

As I said, I'm a slow starter. The first bogie pivot section took me ages. The second one was a lot quicker to fabricate. I hope things will swing along nicely with the rest of the truss work tomorrow, but this afternoon I am switching attention to 57xx.

Surely the better way to proceed is to form up the inner longitudinals [8 & 9] and use these as guides/clamps [with some of your blue tack stuff] until they, in turn, are fitted in place. Everything will self-align then.

It never occurred to me to try and do it the way you have + if you did it that way you would you would not have worry about centreing the various cross trusses/plates. These obviously have to stop short of the edges of the chassis web to facilitate the fitting of the solebars latter.

Remember, you will need to open out the slots slightly on parts 8 & 9 to clear parts 3 & 4 [after these have been fitted to each part 2].

DJP
 

Heather Kay

Western Thunderer
Surely the better way to proceed is to form up the inner longitudinals [8 & 9] and use these as guides/clamps [with some of your blue tack stuff] until they, in turn, are fitted in place. Everything will self-align then.


There's an idea. Other builders, take note. :thumbs:

I'd like to plead lack of experience building MMP kits. If I'd a couple under my belt, I may well have thought of using other components as a form of jig to aid with this part of the build. The idea, at this stage, obviously hadn't dropped. Bear in mind, though, I am pretty much following the recipe as provided. I'm aware you expect some builders to extemporise on the theme, but I'm not that confident yet.
 

Ian G

Western Thunderer
I have only built the Dogfish kits of the range, but found the chassis for ease of alignment was to dry fit all the main chassis componants ie base/sole bars and W irons together before soldering, this kept every thing square, not knowing the MK 1 kits but assuming that you have enough forms of clamps you could do the same with the underframe.

Ian G
 

ZiderHead

Western Thunderer
I … found the chassis for ease of alignment was to dry fit all the main chassis components i.e. base/sole bars and W irons together before soldering, this kept every thing square …


Ive done exactly the same on a thick glass bathroom shelf with various weights on top of the whole lot, that way you can jiggle it about and be sure the vertical pieces all seat nicely into the etched grooves and everything is flat and square. The structure is surprisingly rigid even before soldering up - real a tribute to the tolerances of the etching :thumbs:
 

Pugsley

Western Thunderer
There's something about the first cut that I find hard. I spend ages thinking about things before I make the effort. I don't know whether this is because I'm afraid of making a mess of things right off the bat, or it's just a big step to cut an etched work of art. Anyway, I've started.
I think that applies to nearly all of us to one extent or another, I often spend a fair bit of time contemplating before actually doing, with most things modelling related.

The first step is nearly always the hardest! It does tend to get a bit easier once you're in to the swing of things though, I find.
 

Heather Kay

Western Thunderer
I think it's me. Nothing I touch this week seems to go to plan.

I felt brave enough to add some more parts to this build today, so I took on board David's idea of using the underframe longitudinals as jigs. If you're faint of heart, you won't enjoy trying to part the components from their protective etch. I can liken it to cutting an intricate pattern for a doily made of spider's silk. I haven't actually figured out how I'm going to form any of the bends at this stage.

Anyway, a dry fit to see how things fit.

IMG_7483.jpg

That end looks okay.

IMG_7484.jpg

So does the other.

IMG_7485.jpg

So why is that happening? I've checked and rechecked the bogie mount cross beams, and as far as I can tell they are spot on in their half-etch slots.

From another angle, here's a shot to show the slots on the longitudinal do actually match with those on the main floor web.

IMG_7487.jpg

I am flummoxed. Have I done something wrong? If so, what could it possibly be?
 

Bob Reid

Western Thunderer
Heather,

I don't think it's a case of having done something wrong or a fault in the etched components however if you form up 90deg. bend in the flanges of the two longitudinals (parts 8 & 9)? I think you'll find the issue disappears...

regards
 

djparkins

Western Thunderer
I haven't actually figured out how I'm going to form any of the bends at this stage.

I am flummoxed. Have I done something wrong? If so, what could it possibly be?

ooh err missus! - I've checked the CAD drawing and the central girders are 443.3mm WITHOUT any etch factor - so around 443.15 actual, I'd say. The distance between the inside faces of the buffer beams is 443.32 - so there is just a little leeway. Also checked all the intermediate distances and all spacings line up exactly [or to 100th of a mm!] - so I cannot explain it at all. Force the sods in!

What is the problem with a Hold & Fold for making the fold? Tamiya Bending pliers are great too - I use those on the seats you have in the kit.

DJP
 

Heather Kay

Western Thunderer
I don't think it's a case of having done something wrong or a fault in the etched components however if you form up 90deg. bend in the flanges of the two longitudinals (parts 8 & 9)? I think you'll find the issue disappears...


What alchemy is this? :eek:

I folded up the ends of part 8, as well as the belly truss angle. It still bows. I think I can see what's awry, and the simple fix is to widen one end slot where it intersects with the bogie crossbeam.

Still not sure where things are amiss, though. :oops:
 
Top