Mercian 0-4-0 0-4-0 Garratt, Heljan 37 & Kerr Stuart Wren

[jbe]

Giles,

 

Another coming from references on NGRM. I am following with interest, not to say trepidation, as to what horrors you uncover next!

 

There was an article in the May 2013 Gauge 0 Guild Gazette building one of these kits. If you would like me to scan and send you a copy let me know.

 

Julian

[Giles]

Thanks for the heads-up, Julian - I've found that now..... It's always interesting to see someone else's experience!

 

I thought I'd fit the sand boxes about now, but something didn't quite chime right in my memory, and so I looked at photos I had and the previous work I'd done, to find that the inner 'buffer' beam of the front engine is different to that of the rear engine - and the one supplied are to the pattern of the rear engine. ( see earlier photos for supplied)

 

I've therefore chopped the fitted one about to resemble  the actual more closely. This needs to clear the reversing linkage in reality - but I don't know what's supplied or it if would have been a problem so far as the kit is concerned. You'll also notice that where I cranked the beam out to clear the wheels, I have now back-filled the void with milliput.  This will tidy it up immensely after painting.

 

The sandboxes now fitted, and a hole drilled to bring the wires out to link the two engines together electrically.

Edited February 14, 2014 by Giles

[Giles]

The coupling rods have very limited clearance with the cross-head, and so every effort is made to reduce thicknesses!  The front end is secured by a reversed top-hat bush, tapped 10BA, filed down to just over coupling rod thickness. There is a very thin washer between the rod/top-hat and the wheel boss.

 

This is progress so far - I've also replaced the white metal tank vent with copper tube (stronger, and it's got a hole in...), and fitted the brake gear. It runs beautifully, but then it's got no valve gear, yet. 

I think I shall leave the front engine here, and build up the boiler cradle and rear engine to a similar level, so I can see what interferes with what..... I'm also missing a couple of castings which I'm sure Trevor will kindly sort out.

 

Edited February 14, 2014 by Giles

[Giles]

Reference:

 

On the Bressingham loco, the Front Engine lubricator is on the Off Side, and needs a hole in the foot plate.

 

Edited February 14, 2014 by Giles

[Giles]

I've been building up the body of the rear engine - and to the most part, there is no problem - it's not easy - but that's the nature of it. The only skin-crawler was this etch, which is the bunker back sheet. Note the half etched dots for the rivets, and how they run off....... this makes it very difficult to put a straight row of rivets in, as many of them are half in a hole, and half not......

 

 

 

Great care should be taken when folding up the tank etches ( both front and rear engines) to get a really tight fold, so the tabs and vertical up-stands don't protrude any further out from the line of the base - otherwise gaps will appear when the wrapper is soldered on! 

 

 

Also note that all the fixing nuts have to be filed down on one side to fit. Annoying, as there is no reason why all the holes couldn't have been etched 2mm further in-board to prevent this.....

[Giles]

The 1824 only protrudes a few mm, and is very acceptable! As I've already said, the uplift in performance is very significant, regarding slow-speed running (and power)  

 

 

The Bunker/tank is assembled, with sand boxes fitted (these centre to the riveted panel of the wrapper). I'm missing the top castings at the moment, but I'm hoping Mercian can supply these. I've also fitted the front lifting eyes (not supplied in the kit) and the tank vent pipe (also not supplied)

 

 

 

 

 

I needed to reduce some washers in thickness to take out axle side play - and this is the easiest way to hold them for filing

 

 

 

Two running engines so far...

 

[Giles]

I've added all the sanding pipes to both engines whilst I'm at it., and before I get tempted to fit slide bars etc... 

 

 

And then on to the boiler cradle. This went together fine, although I have added the middle vertical stretchers - either side of the flat plate with four hole in it.  I've cheated slightly as I've robbed these off the version I was scratch-building years ago..... They will be reasonably visible under the boiler when it's done, so I think it's worth putting them in. (they're not supplied with the kit)

 

 

At this stage, I've also been filing down the brass bearings that form the engine bogie pivots, to make sure the Boiler Cradle ride height is correct. The side valances on the cradle should be the same height as the valances on the engines so it all lines through nicely...... (not shown)

Edited February 25, 2014 by Giles

[Giles]

_{The bogie pivots have been next on the list. A length of brass tube, 3/16" dia is provided to use for this, in conjunction with a pair of top hat bearings. However, if you simply use this combination, you will have bogies that rotate from side to side, but have no other form of articulation. This is what's known as a bad idea, and will result in bad running, and quite possibly de-railments. The engines, just like coach bogies, must have some ability to rock fore and aft, and one bogie at least must be able to rock from side to side.}

 

_{There are at least two viable ways of doing this (sensibly). One is to use the supplied tube, and open out the 'loose' top hat bearing into a taper, so that you get your rocking freedom that way, and the second method is probably the harder way (which is presumably why I did it....) and that is to make a new pin from solid with a basic ball joint incorporated (at a very simple level).}

_{I then cross-drilled the protruding bit of the pin to take a piece of bent wire ( or a teeny 'R' clip if I can find one) which will hold the engines on to the cradle.}

 

_{Either will work, but one way or another, you do need to introduce some sort of articulation.}

 

 

 

 

 

 

 

Edited March 15, 2014 by Giles

[Giles]

This afternoon I've been having a look at the cab.

I've known for a while that the roof curve of the front and back sheets is asymmetrical, and that one side of the etch is higher than the other. This means that both etches need truing up by flipping one on top of the other, and filing the larger one down to meet the smaller..... etc..... this results in a shortening of about 1mm, and necessitates the cab sides being shorted by 1mm to match - OFF THE BOTTOM. this means you lose the half etched rivets which have to be replaced.

It might sound a bit of a kerfuffle, and it is... but a cab whose panels don't meet up draws the eye to my mind, and getting it right looks sooo much better, and I shall sleep at nights......

 

I ended up reworking a fair amount of rivets to get them in a more reasonable position. Incidentally, what the instructions don't say (which would be helpful) is that the sides go INSIDE the ends - joint wise (overall cab front-to-back of 35mm which is the correct 5'- 0 1/4"

 

 

 

[Sheffield]

I had understood the Mercian kits were reasonable good. Is this Garratt kit unusual, or am I likely to encounter these sort of problems with their other kits? 

[Giles]

I've never built a Mercian kit before - so I'm not in a position to speak from first-hand knowledge. I would say that this one perhaps has had unusually difficult birthing pains.......

 

 

I'm now looking at the boiler - the etch of which has been through a roller, slightly on the skew. One of the reasons I'm looking at it carefully is that it is a few mm shorter than my scratch-built one (and 1mm smaller in diameter) the correct diameter shout be 38mm (5' - 5" over cladding) and the etch allows for 37mm dia.. The Manchester drawings show the front of the smoke box finishing directly over the centre line of the driving wheels - (which is where my scratch-built boiler ended up) and it looks to me as if the kit boiler may fall a little short - so I shall investigate before I commit.

 

Similarly the firebox wrapper is sooo wrong. The left hand side (incorrect) is the same as the right hand side (correct), and the rivets for punching have been half etched on the face, instead of the back..... I'm therefore considering making a new wrapper and using my old scratch-built boiler! But we'll see after I've slept on it and double checked the lengths. Whichever option I choose won't be straight forward.

[Phil Parker]

I had understood the Mercian kits were reasonable good. Is this Garratt kit unusual, or am I likely to encounter these sort of problems with their other kits? 

 

I've built a few and while they aren't beginners kits in the most part, the Garratt is more trouble than most. Mind you, it's more kit than most too! The range includes designs from several people and several old ranges - I've found Jim's work to need more work than others. Some of the kits fall together though. I've writen up the builds on my blog - Hudswell Clarke, WD Barclay

 

The Garratt does go together but then I was less familiar with the prototype than Giles and happily accepted the boiler and firebox wrappers as supplied. Now I've climbed over the real thing.

 

After-sales service is good though. Not many kitmakers offer to replace parts damaged by the modeller for free if you send them back with an SAE! Trevor is a nice bloke to chat to at exhibitions too.

[Pete Harvey]

Guys I know this model is 7mm and Industrial but is it Standard or Narrow Gauge?

 

A very nice build thread thanks for posting it.

Edited March 2, 2014 by Pete Harvey

[Phil Parker]

Standard gauge - Based on the 4 industrial Garratts used in the UK.

[Pete Harvey]

Thank you Phil

[Giles]

I decided to cannibalise my old scratch-built boiler, as I wanted to get the extra 3mm length back (5 inches, scale), however, I did have to reduce the diameter down to 37mm (rather than the correct 38mm) in order not to create more problems for myself, as the frames aren't quite wide enough otherwise.

 

I then needed to re-create the detail on the bare boiler. Joints in the cladding were done by using a scriber and heavily scoring the line. Rivets were achieved by drilling 0.5mm, inserting hoops of 0.5mm brass wire, and soldering the reverse side, followed by trilling and dressing down.

 

Note, even if you are using the supplied boiler, the chimney isn't actually supposed to be centred to the smokebox. It should be slightly forward of the centreline - with the chimney centre 10mm back from the front of the smokebox.

 

 

Rivets trimmed and dressed

 

New, longer boiler next to supplied wrapper

[Giles]

Pleasingly, some replacement castings arrived from Mercian, as I was missing a pair of sand box fillers - so those are now fitted on the rear engine....

 

The next job on the list is a new firebox wrapper. A direct copy of the supplied one, but with the rivets on the outside, and the washout plugs on the left hand side corrected to off-set from the right hand (washout plugs are positioned to enable the entire crown to be cleaned and inspected between the rows of stays so far as possible).

 

The wrapper is then supposed to solder round a three-sided former, which is a bit of a fiddle - so I decided to add a fourth side to the former to a) give it some rigidity and b) give another surface to solder to. This actually made the job very much easier.

 

 

Before attaching the wrapper, one has to add the separate washout plugs. There is a very simple etch provided, which I didn't find very plausible. I therefore chose to add another layer of brass to the back of the wrapper, drill through from the front, open it out full diameter with a tapered reamer, so I got the appearance of the thickness of cladding and insulation, and then added a second layer of brass, which I drilled and tapped 8BA. 

 

 

 

Taking an off cut of 8BA bolt, I put it in a pin-vise, and filed a square on the end to form a wash out plug, which then screwed into the recessed thread. ( X 6)

 

 

[Giles]

After soldering the plugs in, the wrapper solders onto the former, and the white-metal throat-plate solders onto that. The throat-plate casting was trimmed off at the bottom (flush with the frames) as it represents the cladding, rather than the firebox itself - and the cladding actually does stop short on the real thing.

 

 

 

 

I order to fit the firebox into the boiler cradle, I found I had to reduce the square plate between the frames by about 2mm (which by my reckoning was oversize anyway)

 

 

Because the loco will be fitted with DCC sound eventually - and I don't quite know how I'm going to sort it - I have cut holes in the underside of the firebox, and in the centre of the throat-plate, so as to keep as much access open as possible.

Edited March 14, 2014 by Giles

[Giles]

It has become obvious that the boiler can't be 'removable' for a variety of reasons - especially the ash pan, which is too long to fit through the gap in the frames. I have therefore soldered the firebox onto the cab front, having made sure it's at the right height, and centred to the cab.

 

 

 

The ash pan gets built up next - reasonably straight-forward, when you work out what shape it's all supposed to be...

 

 

This unit then solders on to the underside of the firebox (after I cut a hole in the underside, just in case!)

 

Incidentally, if this thread is a waste of everyone's time - for God's sake be kind and tell me, and save me the trouble....!

Edited March 14, 2014 by Giles

[flexible_coupling]

It's excellent and frightening. I only hope that there's a chance in hell that the kit will be suitably improved on the strength of your efforts..... 

[Giles]

....the hole I cut in the bottom of the firebox..... The firebox was very simply soldered on the the cab front by placing a pice of solder (and flux) along this joint on the under side, and quickly heating it with a flame until it 'flashed'

 

 

Thrash pan in place, and all in situ. The ash pan is extremely close to rail level - but so is the real thing (on the Bressingham, at any rate) it may be a mm too low but not much more than that. There is a fairly straight forward mod I can do if it proves to be a problem with the steam pipe and brake gear, but we'll see.

It will be smoke box saddle and mount the boiler next.

 

 

One think I forgot to mention, when I assembled the articulated units as shown when in swung the rear engine as if for a left hand curve, the boiler unit tilted to the left....... This proved to be the coal shute fouling on the cab back plate, as the coal Shute isn't quite central, and nor is the rear engine body... The answer was to open out the square aperture in the cab back sheet to allow the coal Shute to clear at full swing.

Edited March 15, 2014 by Giles

[Giles]

It's excellent and frightening. I only hope that there's a chance in hell that the kit will be suitably improved on the strength of your efforts.....

 

Thanks! I'm not so very sure it will, but I'm trying to detail all this so that anyone who does want to build one has a bit more information to go on, and knows what to look out for. Obviously they don't have to go to the trouble of making new wrappers and that sort of thing, but knowing about things is half the battle!

(And it's a nice prototype!)

[Phil Parker]

Having built 2 - the model as produced from the kit is OK. The version Giles will produce is superb.

 

It will all come down to economics - can you justify many hundreds of pounds extra development for such a specialised prototype?

[ngtrains.com]

It will all come down to economics - can you justify many hundreds of pounds extra development for such a specialised prototype?

 

I suspect it would be worse than "extra" development but would in effect be a case of starting again. The reason I think this is that this kit dates from when the artwork was hand drawn (which is actually the source/cause of some of its errors) and I think its true to say none of the etchers can now work with hand drawn artwork. You could supply additional parts produced by today's methods but any fundamental change/improvement to the parts Giles has highlighted as having fundamental shape issue would mean starting from scratch in CAD.

 

Given that a large part of the demand has been satisfied by this less than perfect kit the few extra that might sell won't justify the effort and cost.

 

I have one I started a long time ago (bought mine off Jim Harris) and am now waiting for Giles to finish his to sort it all out before I go any further

[Phil Parker]

One cause of errors was the lack of access to the protottype. I'm told that Bressingham wouldn't let them see one side of it!

 

Mind you, I doubt a kit or any other type of model will even be "perfect". Some will be better than others. A top-notch builder will always take the opportunity to do a bit of work to life the model. Others will make changes to suit their prefered way of working. As long as you are happy with the finished model it doesn't matter.