DJH/Tower Models Streamlined Coronation

[Rob Pulham]

On Easter Sunday afternoon I had a phone call from a gent that puts a lot of work my way asking if I could fit in building a DJH Streamlined Coronation as soon as possible. The Gent that I am building the J6 for is in no rush so I decided to have a bash.

 

The kit was duly delivered on Sunday evening and by bedtime I had the basic tender chassis together.

 

Another couple of hours on Monday morning had the tender chassis complete, so far so good.

 

 

 

 

To a degree I feel that any criticism that I make of this kit is a bit like sour grapes given that I chose the David Andrews kit over the Tower/DJH version when I bought mine and I have subsequently decided to sell it unbuilt to concentrate on my LNER stuff.

 

That said, hiding what I find doesn't help anyone else who may decide to build one of these.

 

The key issue with the tender chassis is that the cross members that fit between the wheels are  a single half etched layer in the middle section, which makes them very vulnerable to bending. This and other areas where key parts are a single half etched layer (more on that later) are particularly noticeable to me when this build comes right on the heels of building the MOK LMS tender which is prototypically similar in many respects.

 

Although I don't know the name of the loco that the model is to ultimately represent I have been asked to build it as one of the double chimney red ones - Apparently there were some differences on the red ones over the first few blue ones (I had originally planned to build mine as Duchess of Hamilton in Blue when Coronation was masquerading as DOH while DOH went to America masquerading as Coronation, confused yet.....). Luckily the kit also came with a loan of the Wild Swan/NRM Loco Priles book for the Coronation Pacifics.

Edited April 30, 2018 by Rob Pulham

[Rob Pulham]

Making a start on the upperworks, the tender sides are battleship plate thickness. They come pre bent to shape to follow the bulkheads - what a shame the bends were too low

 

 

 

I used my my cheap cooks torch bought from Lidl just before christmas. I have found it's too hot and uncontrollable for soldering but it's great for annealing.

 

 

 

However, before you get to the tender sides in the instructions, the next section has you making up the coal chute and coal pusher which went together perfectly.

 

 

Edited for double posting

 

Edited May 1, 2018 by Rob Pulham

[Rob Pulham]

Once the rear bulkhead was soldered in, next up I concentrated on getting the many details on the rear of the tender added.

 

 

 

 

It's quite busy back there...

Edited May 2, 2018 by Rob Pulham

[Rob Pulham]

Following on as you might expect from detailing the rear I started adding to the front Bulkhead and the Inner coal space.

 

 

 

 

 

Now getting nearer to the finish line for the tender at least.

[Rob Pulham]

 

Apologies for the slight step back in time on this one but my trip to the NRM last Friday afforded me this comparison shot:

 

 

This was one of the better shots most were quite poor due to the abysmal lighting....

 

Apologies for the slight step back in time on this one but

[Revolution Ben]

 

Hi Rob,

 

Thanks for taking the time to post these - nice job so far.

 

What is the conduit along the right side of the coal spare in the tender for?

 

Cheers

 

Ben A.

[Dave Holt]

Hi Rob,

 

Thanks for taking the time to post these - nice job so far.

 

What is the conduit along the right side of the coal spare in the tender for?

 

Cheers

 

Ben A.

It's the operating rod for the coal pusher. There's a crank and rod inside the cover at the rear of the coal space.

Dave.

[Rob Pulham]

Thanks Dave

[Rob Pulham]

The final chapter on the tender ends.

 

 

 

 

The axleboxes will go on after painting.

 

On the conservative side I have 49 hours in the tender alone. I am now on with the loco chassis.

[Rob Pulham]

So it's onto the loco chassis,

 

 

 

 

 

 

 

 

Which brought me to the end of drawing number 2 of the chassis instructions.

 

I made one minor error in that I got one of the chassis spacers/supports the wrong way up which meant that the hole for the brake cylinder was in the wrong place. Rather than take the chassis apart again I just redrilled the hole at the other end of the spacer and filed the tabs of a couple of brackets that should have fit into some slots. Job done and brakes fitted as they should be.

[Rob Pulham]

I was cracking on quite nicely with the chassis but when I got to the next phase of the instructions I found one of the castings missing.

 

This is the offending article, there should be one at each side.

 

After umming and ahhing as to what to do I decided it would be simpler to scratch another than to wait for the owner to source one from Tower/DJH.

 

Poor photo  but this is it made from scrap etch and some wire filed half round.

 

 

 

 

Next saw me make up the coupling rods which all went swimmingly until I got to pinning them together at the joint. The instructions have you tapping one side 12ba to screw a cast threaded pin into. Having done the first side I quickly realised that the thread on the pin is way smaller than 12 ba Bah!! 

 

The other side I tapped 14ba and I ran a 14ba die down the cast thread,  I screwed it into the tapped hole and the threaded section promptly broke off in the hole The next task is to solder the pins into the back of the hole as I would have done with a rivet of Premier Rods. Onwards and Upwards.....

[brossard]

Fascinating stuff Rob.  You really are good at this.  Things are coming along rapidly and it looks a lovely model.

 

Cheers

 

John

[Rob Pulham]

Thanks John,

 

I now have a second one to do so that should be easier now I have worked out the quirks of the first kit.

[N15class]

Surprised you didn't build them together. It still saves a lot of getting the head around it a second time.

[Rob Pulham]

Surprised you didn't build them together. It still saves a lot of getting the head around it a second time.

Hi Peter,

 

I haven't got it yet but it's in the pipeline so to speak or I would have done as you suggest. After talking to Nick Dunhill about why he prefers to build two locos at once I am quite keen to try a dual build, but so far I only seem to have one example of each kit that I have - bring on the lottery win

[Rob Pulham]

Following on my my note on the coupling rods I managed to get a couple of photos of them now that they are soldered up.

 

 

 

And then a couple that will hopefully show how much I had to file out of the cylinder castings....

 

 

 

Essentially the slots bottom left and top right were almost full of whitemetal so I used an older square file to remove the material. Now that I have the lathe with the milling attachment I suspect that I might have used a burr to mill out the material much more efficiently. Something to remember should I encounter anything similar in the future.

[Petebe]

Hi Rob

 

A bit late to the party. Looking very good.

 

I shall be following this build with great interest.

 

Pete

[Rob Pulham]

After doing battle with the cylinders and struggling with a drill bit broken off in one of the valve guides which I have yet to resolve (but I do have a fall back position should I need it) I decided that for a bit of light relief I would make up the bogie and trailing truck.

 

I started with the trailing truck for now other reason than I had some of the bit's already removed from the fret during the course of removing other bits.

 

 

 

 

Sadly I had got to this bit when I realised that I had made an error in my interpretation of the instructions. You get two options of spring/axle box for the trailing truck. You get an axle box and full thickness spring combined and an etched spring separate axle box and some hanger castings. There are also a pair of thinner springs which I had attached as in the photos above.

 

The idea being that you use the full thickness castings for loco where they are to be used on track radius of greater than 7 feet or use the etched ones for less than 7 feet radius. It was only when looking at the bogie that I realised the the thinner cast springs were in fact for the bogie rather than the trailing truck and it all made sense. thankfully it was the work of a few minutes to swap them over and put the etched ones where they belong. There were some castings provided for the spring hangers as I mentioned but 2 of them were missing so I cut some off the thicker castings to make up the set.

 

[Rob Pulham]

With the trailing truck behind me (see what I did there), I started on the bogie.

 

Sadly having rescued the and fitted the springs where they should go you don't see much of them once it's assembled.

 

 

Now you see them....

 

 

Now you don't....

 

 

 

 

I also made a start on the valve gear but more on that later.

[Rob Pulham]

Despite many distractions recently I have made slow progress on the Coronation.

 

One of the easier wins over the weekend was to epoxy the balance weights on - the instructions have you do this much earlier in the build but I seem to have a tendency to do them as late as possible and I am not sure why.

 

Then on to the fun bits, I wanted to make the valve gear removable for painting so some mods were needed

 

This is what the front of the frames looked like with slots where the cylinders fed through to attach to the top of the frame spacer.

 

 

This was what they look like after a visit from my piercing saw.

 

 

Then I needed to make some spacers to attach the two cylinders together

 

 

Doing this meant that the 2mm diameter screws provided were not long enough so I retapped the holes 8BA and added some longer 8 ba screws. to hold them on.

 

next I soldered the slide bars to the motion bracket frame and started to assemble the valve gear

 

 

DJH provide 14ba screws/nut to assemble the valve gear which I have used but I have also done a belt and braces approach by tapping all the holes 14ba too which allows the nut to be locked on. Most of them also needed to be filed back for clearance purposes.

 

 

I fitted the motor into the basic chassis and ran it for a while with the connecting rods attached. It was a good sign that nothing decided to unscrew itself while it ran (which can be a sign of something amiss).

 

Hopefully the next session will see the valve gear fitted and tested before stripping it back down ready for Warren to paint.

[Rob Pulham]

From "Woe to Recovery", it sounds like the title of a book or film

 

Where do I start, when assembling the cylinders, one of the jobs was to drill out the valve guides. When I drilled the first one I managed to break a drill bit of in the middle of it. I attempted to get it out by cutting off the rear spigot and drilling small holes around the end of the drill bit but didn't succeed in getting it out. I popped a bit of rod in the other end and it went a fair way in so I reasoned that I might get away with shortening the rod because the valve stems don't appear to move that much. 

 

This was what was peeking out of the end of the casting but it wasn't quite enough to grip.

 

 

When I broke the drill bit off in the first casting, I decided to make a collet to allow me to better grip the second casting without damage and I was able to drill the second one without issue.

This is the collet and another view of my attempts to remove the offending drill bit stub

 

 

I advised the gent that I am building it for what had happened and that we may need a spare casting but I was going to attempt to work my way past it. During the assembly of the valve gear I carefully measured the amount of valve stem and progressively shortened it until it fit.

 

Fast forward to giving it a test run and it dropped out of the guide jamming up the valve gear.

 

When this happened on Tuesday evening I took the wise course and stopped to ponder.

 

First thing Wednesday morning as I was getting up for work, Chris said I have the solution to getting the drill bit out and proceeded to explain the idea that she had dreamt while asleep. The idea was basically, to cut a slit down the side of the casting to relieve the grip from the whitemetal and then drift the stub out.

 

After dinner I went into the workshop to take the valve gear to bits and unsolder the valve guide casting. I then out the casting in the collet and after a bit of a fiddle managed to get the seam of the casting lined up with the slit in the collet and gripped in the vice.

 

 

 

That done and using an old Exacto Blade, I proceeded to cut through the side of the casting using some odour free white spirit as a lubricant (made more essential by the fact that this Exacto blade has a slight kink at one end). I kept steadily cutting until I felt the blade grating on the side of the drill bit stub (why I used an old blade) and then removed the casting from the vice.

 

 

The next bit's I forgot to take photos of but using another broken drill bit as a drift I placed the bottom end of the casting on a block of wood which I have on my bench with the protruding stub of the drill over a hole that I had drilled when going through something previously (it doesn't quite look like swiss cheese but there are a good few holes in it).

 

The drift moved the drill bit out a few millimetres further, to the point where I was able to grip it in a pin vice. I was then able to grip the casting in my hand and a twist of the pin vice had it free.

 

 

I then filled the seam with 70 degree solder and using the collet as a heat sink I soldered the casting back on and cleaned it up. In the photo below the seam is uppermost and is to all intents and purposes invisible.

 

 

Lastly I dismantled and remade the valve stem. The original is two layers of etch. I made the replacement from a piece of 1.10mm brass rod. I am not too happy with the boss so I plan to have another go later this morning.

 

This is the shortened version.

 

This is with the bit that I had cut off

 

Lastly this is the replacement.

[jwealleans]

Have you done anything with the cast boiler yet? I remember Graham Varley showing me a red one of these he'd built and painted. Mind you don't put your back out, they weight a ton and a half.

[Rob Pulham]

Have you done anything with the cast boiler yet? I remember Graham Varley showing me a red one of these he'd built and painted. Mind you don't put your back out, they weight a ton and a half.

 

Hi Jonathan,

 

No, not yet. That will hopefully be Sunday's destination. - I am demoing at Doncaster show tomorrow

 

I have a few more small details to add to the chassis (reversing lever+speedo) but now that I have this bit sorted I should be able to crack on with the body.

[Rob Pulham]

After Wednesday's woe yesterday was Sunshine and Joy. She runs at last. There are a couple of the fixings to sort out but the motion all works as intended after my repairs. I still need to add the reversing shaft and the speedo but then I think that I am onto the body.

 

 

 

 

Edited June 1, 2018 by Rob Pulham

[Rob Pulham]

And then there were two!

 

I have made a start on the backhead and as I mentioned earlier, now that I have the second kit to build, it makes sense to do them both together . - Although I may also do the body in tandem I won't be doing the tender or chassis until later.