4mm Brassmasters Rebuilt Royal Scot, 46109

[Dave Holt]

The cab inner frame has been folded up and loosely placed on the footplate.
Should be a fairly straight forward folding exercise but....The instructions warn to be careful not to distort local to the cab spectacle windows when folding the sides. This seems virtually impossible due to the lack of material to hold. So, despite using a hold-and-fold tool, the front plate did distort and had to be pressed back to shape afterwards. The other problem arose when I tried to place the cab structure on the footplate. The front of the floor interfered with the splashers and framework at the drop section of the footplate. To overcome this, as section of floor has had to be removed using a piercing saw. It would have been a lot easier to do this in the flat rather than with the folded up cab. I wonder if anyone else has experience this, an error in the kit or have I done something significantly wrong?
Cab frame placed loosely on the footplate. Those rearward projections at the top of the sides aren't half vulnerable!


Rear end of the footplate, showing the splashers and support frames that the floor interfered with.


Cab frame with the floor cut away, after folding, to clear the footplate.


Dave.

 

[Dave Holt]

Looking a bit more like a re-built Royal Scot.

Dave.

 

[Dave Holt]

The main structure of the cab is now complete, ready to fit to the footplate once the splasher tops are fitted.
The outer wrapper, various rain strips, roof ventilator and side beading have been added to the inner frame and the temporary stiffening plate removed from inside.




Dave.

 

[Dave Holt]

Whilst pondering the need to move the centre splashers outwards to avoid the risk of shorting, I indicated that I would try the chassis out on the tightest curves on my layout. I've finally got round to doing this before fitting the splasher tops, thus enabling a visual check from above that the centre wheels do not touch inside the splashers.
Even on the tightest curve - leading to the mill coal siding, it was clear that no contact was being made. Phew!
Here the chassis is seen on the cross-over into the loop/yard and also on the very sharply curved (about 900 mm radius, I think) mill siding approach, which a Scot would never be required to negotiate in practice.





The layout boards have been stored indoors for some time, but I was surprised how badly rusted some lengths of the steel rail had become whilst other sections had remained clean and shiny looking. Odd that it hadn't all reacted the same.
Dave.

 

[LarryG]

That length of P4 track you left with me some years ago to photograph your models on is as rusty as hell.

 

[Dave Holt]

Not too much to show, but the cab has been fixed to the footplate and the splasher tops fitted (not in that order!). A couple of small splashers have been created to fit inside the cab front. These are necessary to cover the wheels after parts of the footplate and cab front have been cut away to clear the rear wheels. Up till now, the footplate has been resting on top of the wheels, preventing compression of the springs and leading to some wear marks just from pushing the loco back and forth. It runs a lot freer now there's clearance.
The cab floor has been trimmed to fit and temporarily slotted into place together with the cast back-head. This latter needed trimming to fit round the existing kit splashes and the added extensions.
Chassis with footplate fastened in position and the back-head casting cut away to clear the new splasher arrangements.

The small addition splasher on the RHS can be seen inside the cab. They are a bit bigger than scale, but I wanted to be certain they would clear the wheel flanges with the suspension fully compressed.

Here the cast back-head is tried in position.


Dave.

 

[john lewsey]

Hi Dave I have to say that your modelling is superb
John

 

[Dave Holt]

Thanks, John. That's very kind of you. I just try to keep the visible bits as neat as possible and I like to add as much detail as I can.
Dave.

 

[Dave Holt]

Footplate overlays now fitted. Valance overlays next, then battle commences with the outside motion bracket. Looks like a pig to form to the correct shape.
Overlays in place. You might notice that, in handling the assembly, I've managed to snap off two of the sand box filler plates. Hopefully, they wont be too hard to re-attach.


Dave.

 

[Dave Holt]

Oh dear! Today has been one of disaster followed by partial recovery.
I anticipated that the outside valve gear support frame/bracket would be very difficult to form into its rather complex shape. The first bends went OK but then, when I tried to form the required 1/8" radius 90 degree bends disaster struck and various parts of the etch broke off at the half etched bend lines. So, instead of having a single, complex item, I had about eight separate pieces.
All the modelling time since has been taken up by trying to re-attach the various pieces, using the chassis and footplate as a jig to locate parts for soldering.
In the end, I've got the frame re-assembled except for the parts that go under the slide bars. I've decided it will be best to leave these till after the slide bars have been fixed to the upper section.
Now, where's that darkened room?
Two shots showing the current state. Some cleaning up of excess solder is required.




Dave.

 

[P A D]

Can you stop it Dave, you are putting 7mm boys to shame! An impressive build.....

Regards
Tony

Agreed!

Just had a cruise through this thread and worn out the like button. Superb build.

Cheers,
Peter

 

[Dave Holt]

Thanks for the kind comment, Peter.
Continuing with the valve gear frame/bracket, a substantial tie bar has been fixed across the front to hold the sides together once the centre section of the front plate is removed. On the real thing, this plate across the frames does not exist, with the external brackets rivetted to the outside of the frames. On the model, the arrangement works well but interferes with the inside motion, and in particular, with the expansion link and its supports.
Here's the formed and re-assembled unit with the new tie attached, prior to cutting the centre section away.

And after removal of the centre section. The new cross tie also represents the top flange of the inside motion stretcher where the front feet of the boiler sit.

The modified support frame now allows the inside motion plate to be fitted.




Seen here with the footplate in position.

This work now allows the inside motion bracket to be fixed into the chassis and rear end of the slide bars. The inside motion can then be assembled and fixed in position.
Rather looking forward to this after the stress of sorting the fractured motion frame.
Dave.

 

[john lewsey]

Hi Dave what motor/gearbox are you using
John

 

[Dave Holt]

John.
It started life as a 1616 Portescap but I have used MJT replacement gear box sides to clear the frame spacers.
Dave.

 

[Dave Holt]

The inside valve gear has now been fitted.
A bit of dressing of the crosshead was required to get a smooth action in the slide bars over the whole stroke. I also discovered that the eccentric could not be located without removing the crank axle from the frames. I can see this being required more frequently than the other axles, so I decided to split the one-piece keeper plate between the leading and middle axle so, in future, the crank axle can be removed without disturbing the others.
After some filing back the lower rear edge of the reverser inner lifting arm, to clear the crank bob weight on full compression of the suspension, I'm pleased to say it all turns smoothly with no detectable tight spots.
Here's the inside connecting rod and combination lever fitted to the frames, seen from above and below.




Then the full gear assembled. There's not much clearance between the front corners of the expansion link and the motion plate and new cross stay for the outside support frame. Still, a miss is as good as a mile, as they say.






Dave.

 

[Dave Holt]

Not much modelling just now. I've acquired a small but very painful cut near the tip of my left index finger - might have caught it with the piercing saw but can't remember doing it. It's making it too uncomfortable to try to grip parts between finger and thumb as any pressure on the finger tends to open the wound.
That said, I have finished off the exhaust steam pipe to the injector, ahead of the removable section, already shown. I've had to add a substantial and completely un-prototypical support bracket near the lower end to locate the pipe joint relative to the frames.
Adding these extra details, not envisaged by the kit designer, throws up all sorts of clashes with other parts of the loco. On this case, the top level of the pipe to the inside cylinder passes through the rear cross member of the outside cylinders. I strengthened the reduced depth of the cross member with 0.8 mm brass wire - which did the job, but then it clashed with the top of the inside combination lever at its furthest back position, so the strengthening wire had to be nibbled away local to that.
It all clears now, as shown by the assembly.

On with the bogie once the finger improves.
Dave.

 

[Dave Holt]

Whilst trying not yo overload the finger tip, I decided to make a representation of the exhaust steam passageways between the three cylinders and the smokebox saddle using plastic card, laminated where necessary to represent the required thickness. Not too sure why I've bothered with this detail as once the footplate is on, it's almost impossible to see, even from underneath! Well, it's there now.
It has allowed the square flange on the pipe to the exhaust steam injector to be included.




Some prep work has been done for the front bogie.
The main bogie bottom stretcher and the cast W/M crosshead have been opened up to fit a 2 mm O/D tube which fits over the fixing screw, allowing the latter to be fully tightened (after cutting the tube and screw to length) whilst still allowing the bogie to pivot and slide sideways. The etched extensions to the top edge of the side frames, which I assume are supposed to represent the centre casting, have been removed (one can be seen close to where it used to be attached) so that proper side bearers can to used. The odd shaped part on the left of the photo is the start of this piece on the model.
The external compensating beams have had the half-etched linking piece between the beam and the axlebox removed from what will be the outer face, after bending to shape.


Dave.

 

[Dave Holt]

The slide bars have been fixed to the cylinder frame, ensuring they are square to the cylinder faces in all planes. A trial fit shows the top bars to sit nicely in the support bracket. The connecting rods and cross-heads run smoothly, without any clashes.

Dave.

 

[ullypug]

Very nice work as always Dave
Makes me want to build something...!

 

[Dave Holt]

A bit of progress has been made with the bogie, in among writing and posting Christmas cards. The things that get in the way of modelling!
It's been more of a struggle than it might have been. I couldn't find the side control springs and arranged with Brassmasters to obtain a replacement set. Whilst waiting, I ploughed on with folding the frame etch, enclosing the central cast W/M crosshead in the structure. The instructions stated that the holes for the side control should be opened to 1 mm and 1 mm rod used as the guides.
The problem arose when the new springs arrived and were found to be slightly under 1 mm O/D and about 0.7 mm I/D. In fact, although they would just push on to a 0.7 mm drill bit, they wouldn't go onto nominally 0.7 mm rod because it was 0.02 mm over size.
The solution was to sleeve down the holes in the frames with 1 mm O/D tube and to mount small washers between the inner ends of the springs and the ears on the crosshead. 0.6 mm rod was used as the spring guides. To be honest, although extra unplanned work was required to recover the situation, the side control action is the best I've achieved with a Brassmasters bogie.
The external compensating beams have been made up, as seen below.
Bogie (seen from underneath) and compensating beams.


Close up showing the side control arrangements.


Dave.