Stanier 8F in Scale Seven part 19: water scoop mechanism

I decided for some unknown reason to switch to the tender again. Perhaps because having succeeded with the brakes on the locomotive, I wanted to see if I could do them on the tender whilst the technique was still in my memory! So I measured the clearances, and found to my delight that no adjustment was really needed for ScaleSeven: the brake hangers could be soldered into the inner chassis frame and could be adjusted easily to be the correct clearance for the S7 wheels. Excellent. So I insulated the faces of the brake shoes as before, soldered the brake hangers and retried the running of the tender frames – it still works!
Next in the instructions is the water scoop lift gear. This proved to be a real challenge for me. There are times when I wish I was living in the UK (though not many ….) – the instruction sheet is really deficient in this section: “assembly is per diagrams and photos”; two unlabelled pictures and some difficult-to-decipher diagrams. It would have been much easier to be able to look at the real thing, but instead I had to look on the ‘net for drawings and pictures. It was almost too obscure even for the ubiquitous WWW: Google Images of “Stanier tender water scoop gear” produces almost no useful images!  I eventually found some useful stuff – Some pictures of a model 3500 gallon LMS tender, and most useful were pictures of the Duchess and its tender in a Birmingham museum.  I had to work out from their appearance what all the parts were for, and then how they go together.  I hope I was right.

Small Water scoop mech 001The mechanism is mounted under a crossmember of the tender chassis, and appears to be a rod or axle (moved by a long control beam from the front of the tender) on which a number of cranks are mounted. The ones at the rear end (right of photo. here) are aimed to lift the water scoop itself.

On the same axle are mounted levers which lower another device into the water troughs, the levers seen in the middle of the mech. and protruding to the left in the photo. below.
Small Water scoop mech 002
I’m not sure what this device did in real life – I guess that it was a deflector to channel more water from the edges of the water trough into the scoop?
There is also what I think must be a balance weight for the water scoop attached to the axle, seen in the middle of the mech. above (probably in the wrong position). I added to the thickness of the etched parts which represent this.
To make up the mechanism as seen above needed three parts to the frame (25 x 15 x 15mm), a piece of 1.6mm dia. rod, twelve tiny bits of etched nickel silver, half-a-dozen 1/32 brass pins and a HUGE amount of patience.

Small Water scoop mech 003Here it is in position:

Some of the brake gear is also seen, but no water scoop as yet.
If my deductions were wrong about where everything goes, I’m not sure that I really want to know ….

Stanier 8F in ScaleSeven part 18: injectors

Steam engines usually have two injectors to drive water into the boiler at high pressure.  The Stanier 8F has an “Exhaust Steam Injector” on the right under the cab, and a “Live Steam Injector” on the left.  The MOK kit has lost-wax castings of both, but the instructions are sketchy about how and exactly where to put them.  When I looked at the engineers drawings, it became obvious that the live steam injector molding was incorrect.  There should be four pipes coming off it or going to it.  Water supply above the outgoing water to the boiler, on the inside surface, Live steam supply at the front, and overflow at the back.  The MOK molding had four places for pipes, but two were on the side and two on the rear.  In looking on the ‘net I had found illustrations of the injectors, and information that Laurie Griffin manufactures very good castings of both exhaust and live steam injectors, so I bought some by mail order.

MOK casting on left, Laurie Griffin on right

MOK casting on left, Laurie Griffin on right

 

When they arrived they were clearly a great improvement on the MOK ones in terms of detail, but the Laurie Griffin one was wrong also!  The LG live steam injector only had three pipe fittings!

The LG one looks better, so I have used that one, fitting the overflow pipe to the bottom of the injector.

 

Small Frames with old injectorWhen I had put the exhaust steam injector onto the frames it involved fitting the steam pipe from the cylinders.  It is difficult to form the reverse bend at the rear of the locomotive, and I hadn’t bent it quite correctly, leaving the pipe running at an angle down the frames.

The Laurie Griffin exhaust injector molding includes last bend of this pipe, so it gave me an opportunity to correct this error.

However the injector comes in five pieces, which need to be soldered together, and then the four pipes have to be soldered onto the injector, without any of the other joints becoming un-soldered!  It took me all day today, but here are the final results:

Small Both injectors with pipes 2.Small Both injectors with pipes

 

 

 

 

Click to enlarge.  Clearly they have yet to go in place, but I might paint them first – it will be difficult after they are fitted.  The Laurie Griffin exhaust steam injector (on the left in both pictures above) has exquisite detail, so I don’t want to mess it up with a poor paint job.

 

Stanier 8F in ScaleSeven part 16: Brake Hangers

Brake gear.

A problem with all systems where power is picked up from the rails is that brake shoes realistically close to the wheel treads need to be isolated from those on the other side and from the frames, or else short circuits will occur. DC or DCC, I think. Now my system is going to have no pickups from the driving wheels, but the brakeshoes as made in the kit will short-circuit from one side to the other. What options do I have?

My first thought was to make new brake hangers by acrylic/epoxy molding. So I bought a Sylmasta kit and made molds for the brake hangers for the locomotive and tender.

 

 

Small Brake hanger polyester moldingsI then made castings first in polyester (this was the plastic/resin provided in the molding kit):
These were too friable and brittle, however, so by default I tried molding in Araldite, which was more robust, but full of bubbles:
Small Brake hanger epoxy moldings

Even these looked unlikely to survive very long in general use, though. Contacting friends for advice suggested that I was trying to make castings of too much: it would be better to make castings of just the brake shoes.
However to do that meant filing all the brake shoes off the hangers (fourteen!) and both making and fitting accurate copies of the shoes onto each hanger. Then it occurred to me – I don’t need to take all the brake shoe off, just the surface which will be in contact with the wheel tread.
So I found some 2mm wide Plastikard strip, and have carefully filed sufficient off the surface of the brake shoes to glue a strip of Plastikard onto each shoe.

 

So the one on the left has been filed back, and the ones on the right show the Plastikard in place.

 

 

 

Once I came to try to fit them to the frames the next adjustment became necessary. As the frames are set at nearly the correct prototype width, they are much closer behind the wheels than in Finescale. If the brake hangers are fitted as made, the hangers are too far away from the frames, the shoes are outside the wheel rims and the outside parts of the shoes contact the coupling rods and stop them rotating. So now I became more grateful that the main parts of the brake hangers are metal, not epoxy! The two on the left of the picture above have had the posts from which the hangers are suspended shortened, whilst the right hand one is the original length. I think that this adjustment would have been near-impossible using plastic parts.

Now I just have to fit them, one or two at a time, and make sure the wheels still go round after each fitting.

Stanier 8F in ScaleSeven Part 15: balance weights

Just an update.  Partly because of the difficulty painting behind the driving wheels, and partly because I realised that I needed to put the balance weights on the wheels (and this would probably be much easier if I could lie them flat), I partly dismantled what I had done so far to put together the chassis.  Also I realised that the return cranks were on at an exaggerated angle, and although this makes the valve gear move more satisfyingly, I should probably re-do the soldering to make it more realistic (10 degrees is right).

Of course to put the balance weights on is easier said than done. First of all I had to choose exactly which 8F I wanted to model! I found a picture of number (4)8067 which seems to have the right characteristics: a rivetted tender, balance wheels of the earlier type (not all of the weights are crescents) and based in the north of England. So number 8067 it will be.

Both types of weights are supplied in the MOK etches, as pairs (so four of each shape). Using the S7 Group Slaters wheels makes sandwiching the pairs of etches together relatively easy, one on each side of each wheel: the plastic spokes can be cut back a little to accommodate the etches. Not too much on the outer side, though, as the balance weights stand proud of the rims on the pictures I have seen.

Small Balance weights 1I then filled in the gaps between the etches with Milliput filler.

Now seemed a good time to use Birchwood Casey metal black on the rods and valve gear, to obtain a good “polished steel” finish. I used Hi-Chem “All-Surface Primer” on the wheels (probably only available in Australia, but I’m sure motorcar paint shops anywhere would have a similar product) – it’s a marvellous very thin and very effective metal primer: it sticks to anything, in my experience even glass or granite benchtops! Therein lies a separate story, as you might imagine ….

Small Balance weights 2

 

 

Finally, a “dirty black’ initial topcoat. My engine is going to have a realistic (I hope) weathered appearance.

So there you are.

David

 

Stanier 8F in Scaleseven part 14: putting the boiler on the frames

It’s beginning to look a bit more like an 8F (admittedly I have placed the pony truck in place and the smokebox door just for this picture, though).

Small Boiler meets framesA question however: when I started this project, I saw the picture of a lovely model 8F in brass-and-whitemetal finish. I was looking forward to the day when mine might look similar – but how can that be done if I am also going to have to paint parts of it before I complete construction?
I guess it doesn’t matter really, but if I am to have a realistic painted finish in places like the frames behind the driving wheels, surely this will have to be done by taking the wheels off.  Especially if I wish to have a good finish on parts like the springs, which are right behind the wheels, of course. As you’ll observe from the above picture, I haven’t put the braking gear in place yet. Once I have done that the wheels will be very difficult to take off. At present the wheels can be removed easily, because the excellent design of the MOK kit allows the motion bracket, valve gear and wheels to be removed as a unit.

Small Boiler meets frames 2So, how do other modellers manage it?
How do you make a whole brass-and-whitemetal kit up, and later get a good finish on it, without giving yourself a huge amount of unnecessary work dismantling all the careful modelling done to put it together in the first place?

 

Answer (I think): you cannot.  On the ‘net are articles describing how people have made up a model completely, then have to spend lots of effort systematically pulling them apart so that they can then be painted!  When it comes down to doing that, I do not think pictures of the unpainted model are so important, so I will paint the frames behind the wheels at this stage (and probably most of the stuff in-between the frames also).

Small Chassis dismantled 1First stage, take the wheels and the motion off the frames.  Fortunately this doesn’t prove too difficult.

This will also give the advantage that I can put the balance weights on the wheels whilst they are flat on the desk, rather than mounted on the frames.

Small Chassis dismantled 2The frames themselves will be easy to paint I hope, although I will have to mask off the sliding hornblocks (bearings) for the driving wheels, and avoid painting the compensation mechanism on the insides of the frames.

 

The balance weights will have to be chosen.  I hadn’t realised, but there are many variable configurations of balance weights between difference individual locomotive which are otherwise indistinguishable.  So I will need to find a picture of a locomotive in the area where I want to model (not too important) with a rivetted tender (which I think looks nicer), and then try to match the available parts from my kit to make the appropriate balance weights on my locomotive.  So, where do I find a side-on view of a Stanier 8F, pulling a tender with lots of rivets on the side, on the Settle-Carlisle Railway (or, at a pinch, anywhere in Lancashire or the North-West?

Stanier 8F in S7 part 13: rolling the smokebox.

Onto the best bit (for me) – building the loco body (I’ve never built a tender before, but that should be good as well).  Actually going on to building the superstructure may be good mainly because I am stressed out about making the wheels go around without binding, so when the chassis is complete I breathe a sigh of relief and relax ….
Early on in the build comes the boiler and smokebox construction.  Now the instructions say that both are “pre-rolled”, but only my boiler was treated this way.  The smokebox was a pair of flat etches (there is a beautiful thin overlay with all the detail on it).  So this is the dilemma: I have never tried to roll a piece of flat metal into a cylinder, so is this the right time to start?  Do I risk ruining my lovely MOK kit, or do I beg someone to roll it for me?  If so, who?  Or do I buy a special rolling tool (about $90 here in Aus., which I may never use again)?
The instructions talk about rolling the (much thinner) overlay using a metal bar and some cloth so press it down onto.  So the main structural part of the smokebox should surely be bend-able in the same way ….
So I try rolling the (0.5mm thick) nickel silver sheet with a bar about 25mm diameter, using towelling as a base.  The curve of the result was the sort of bend that on trackwork you could easily run an 0-8-0 around without gauge-widening (that has surely to be the ultimate “in-joke”).
Small Smokebox and boiler 01
However I thought about this for a while and decided that the problem was with the surface that I was rolling the sheet into.  So I used instead of cloth a strip of the neoprene wet-suit material that I use to provide a springy surface for my trackwork.
Using this as a base, the next curve in the smokebox was maybe 20cm diameter, and adding layers of the squashy neoprene allowed a tighter radius to be made.  I had to use a smaller diameter rod as well (about 15mm) but in the end the 38mm diameter smokebox could be formed.  nerve-wracking, but satisfying in the end.
Small Smokebox and boiler 02Having the formers to make the accurate cylinder was useful as well.  This picture shows the copper wire (from mains electricity cable) used to squeeze the inner cylinder of nickel-silver down onto the formers.  Thicker copper to hold it in place, then thinner copper to squeeze the metal down.
Small Smokebox and boiler 03After that it was easy (relatively) and both the smokebox and the taper-boiler could be made accurately.
You can see in the above picture that I slightly over-did the curve on the detail overlay, but that did not matter in the end.
It is now, for the first time, possible to look at a preview of what this kit is going to be like when it is finished.  OK, I accept, it takes a deal of imagination still ….
attachFull46110
David

Stanier 8F in S7 part 12: running the chassis for the first time.

The 8F is progressing well, and I have been able to fit the special parts and run the assembled chassis for the first time!

Small The first run on test track 1

 

It was a great moment to see it move for the first time.  After I cleaned my test track, it ran for the first time with almost no hesitation.

 

Small The first run on test track 2

I decided to try running it with the connecting rods in place but before I try the return cranks, etc.  I had to wait to try out the running until the tender pickups were done.

The third picture shows the tender pickups: the compensation mechanism is still able to work (I have left loops in the wires to allow this, but there’s still a lot of gear to go into those spaces, so I’m not sure how well this will work) and the temporary connections visible going to the loco. chassis on the right. The split axles can be seen.

Small Tender electrics

It doesn’t look much like an 8F, and the motion isn’t all connected yet but it shows that the tender pickups are working and that the assembly so far is acceptable.

It runs better forwards than reverse at the moment, but goes reasonably smoothly at 7V drawing 100-200 mA, and it’s still running without any lubrication.

S7 Stanier 8F Part 11 “Obtain a running chassis”

The instructions are a little terse at times, such as this: “Obtain a running chassis” !

Small Obtain a running chassis 01

After a struggle, this is where I am now at:

 

Motion bracket, etc., in position on the frames.

Motion bracket, etc., in position on the frames.

However it will take a little while to describe how I reached this point!

 

This is what I had constructed so far:

I had bought the special ScaleSeven wheels, but it turned out that  the wheels rims/tyres had been made to S7 standards, but the central boss part of the wheels was far too thick.  I was lucky once again to be able to enlist Richard Davidson’s help, and he used his lathe to thin down the wheel centres by about 0.5mm each.  This extra space on each side would be crucial to allow the wheels and coupling rods to turn behind the slidebars and crossheads without catching.  Even with the wheels thinned down, it is a very tight fit.  It was simply not going to be possible to fit the manufacturer’s crankpins, washers and nuts.

Wheel BoltOnce again, Richard has been the saviour.  He manufactured four specials crankpins – bolts to go through the coupling rods from the outside.

I decided that on the first axle the special crankpin could be used without a washer inside, as the coupling rod was slightly thicker around the crankpin, giving clearance over the wheel centre.  For the second axle, though, a washer would be needed between the special crankpin and the wheel boss, as the articulation in the coupling rod would foul the wheel centre otherwise.  For the third and fourth axles the Slater’s crankpins could be used.

Small Annotated Obtain a running chassis 02Shown here are the different crankpins in place.

When I first put the axles in the frames, bolted the retaining plates to keep them there, attached the coupling rods loosely and turned the chassis over: JOY – the chassis could be pushed forward and the wheels all rotated with minimal binding.  Too easy, as they say here in Aus.

“Too easy” in fact ….  Once I tightened down the crankpins the binding started.  I am not sure what the correct way to sort this out is, but Richard had once shown me how to push the frames along, and when the wheels stopped rotating, move each segment of coupling rod sideways with a pair of forceps to see if it moves: even a little movement shows that this is not the part which has stuck.  When a crankpin with no movement is found, the hole in the coupling rod probably needs to be enlarged (with a small tapered reamer).  I slowly opened out the holes in the coupling rods where the binding was occurring.  At least with the articulated coupling rods this is made easier.  However it also became obvious that on one wheel the countersunk central bolt holding the centre of the wheel to the axle stood out too far and was scraping against the coupling rod – the bolt had to be filed back just a little.

This all seemed to take ages, and the special crankpins were difficult to take out each time – I had to buy a “pin chuck” (like a very small drill chuck) to hold the circular heads of the crankpins.  However in the end I did “obtain a running chassis”, although one without the connecting rods, etc in place.  I couldn’t then resist a trial fitting of my Portescap motor and ABC gearbox, to see it all turn for the first time!

Using the Slaters crankpins and their “top hat” bushes made the coupling rods stand out an unrealistic distance from the wheels, so next action was to thin down the flange of the top hat bushes (almost removing the “rim” of the “top hat”!), and shorten them so that they are only slightly longer than the thickness of the rods.

Small Obtain a running chassis 03After all of this, fitting the cylinder/slidebars/motion bracket assembly revealed that all the work was being rewarded, with a small but definite clearance between the front crankpin and the crosshead on the slidebars.

The connecting rods were still not fitted, so next was to attach these to the crossheads.  There was nothing in the instructions about how to do this.  There is a post coming out of the recess in which the small end of the connecting rod fits, about which the rod will move.  I cut this off flat with the crosshead rear (the was no way it could be allowed to protrude!).  After some thought I measured the post: 2mm diameter, and made two tiny circles of flattened nickel silver wire (curled around a 1.9mm drill, then flatted between a steel ruler and a granite benchtop with a hammer (lucky the household manager was out again).  I could then solder the wire circle around the post to hold the connecting rod in place.

Small Obtain a running chassis 05Connecting the connecting rod then allowed me to see the next difficulty – the expansion links have to be made very carefully so as to hang just wide of the connecting rod.  I had not done that (it’s not easy to see this difficulty before this latest part of the construction), so some reconstruction is going to be needed now.

 

S7 Stanier 8F Part 9 Initial stages of the tender

Whilst waiting for parts needed for the main locomotive to come from the UK, I have started on the tender.  The model kit is designed to have a “compensation” mechanism, which allows the rear two axles to move up and down independently.  The front axle is fixed.  This is shown in the picture below.

Small Tender compensation mech 1There are two inner plates which rock about the bar which can be seen crossing between the frames.  On each plate there are two “loose links” which carry the axle bearings, and allow the axles to move at small angles in the plane perpendicular to the axis along the tender.  The loose links are not shown in the picture.

These loose links I have had to modify anyway, to take double-sided circuit board, as part of the adaptation which will allow the wheels to be isolated from the frame, and allow electrical pick-up through a “split-axle” design.  On the picture above, for the fixed axle at the front of the tender I have already soldered on the circuit board [it is not exactly straight, but this will be unseen and unimportant when the model is complete].

Small Insulated Loose LinksThis picture shows the loose links adapted with circuit board.  The left-hand one has the double sided circuit-board soldered to the link.  The loose links will have the side parts bent back at right-angles and slid through the slots seen on either side of the bearing holes in the rocker arms seen in the top picture.

The central loose link, seen with the c-b underneath, has had the loose link bored out with a countersink, which then allows the brass bearing to be inserted from the other side, remaining electrically isolated from the surface on the side closer to the camera, which will be in contact with the frame of the tender.  This is seen on the right hand loose link.

Small Isolated bearingsThis way the wheels and axle are isolated from the frames although firmly fixed to the loose links, or main frames in the case of the fixed front axle, seen here.

Fortunately S7 wheels have a wider back-to-back measurement than normal Finescale 0-gauge wheels, allowing the insertion of the c-b.

It is all a complex way of allowing the rear two axles to rock independent of each other.  I hope it works, with all the modification to take my split-axle pickup method!

Meanwhile the wheels and other items have arrived from England, and I have been able to put the coupling rods, driving wheels and hornblocks all together into the locomotive frames.

Small Wheels and Coupling rodsI was not looking forward to this stage, actually, because of my previous experiences – two 0-4-0 locomotives and an 0-6-0, all of which I had problems with at this stage.  In all three cases the coupled wheels had suffered from a lot of binding as the wheels went around, presumably because the coupling rods had slight different distances between the crankpins to the distances between the wheel centres.  So the thought of all the adjustments necessary on an 0-8-0, and the enlargement of all the coupling rods crankpin holes was not pleasant.

This kit is in a different league.

I put it all together, turned it over, pushed the frames forward, and the wheels rotated perfectly.  No binding.  Even without any additional weight on the frames.  MOK clearly have made the kit with perfect dimensional accuracy, although the correctly articulated coupling rods may help also.  Whatever it is doesn’t really matter – it works!

Look carefully on the picture of the frames and you can see the 14BA nuts to be used to put the keeper plates on, to hold the hornblocks in place.  14BA is small, and MOK suggest 16BA!