Copenhagen Fields & TFW’s workshop

[Tim Watson]

Back to working on the big engine (Raven 4-6-2 class) with lubricators, sandbox filers and a small footplate handrail.

The lubricator was ‘lost plastic’ cast from a very detailed 3DP courtesy of Simon Grand. It is amazing how the detail has picked up in the casting. 

The base peg was used to help locate the steel running plate that is also held down by magnets. The sand box filler also started off as a peg through a hole into the brass sub-structure. As always, easier to start with a large component - to hold whilst soldering - and then trim to size. 

The little nickel silver handrail was bent up with two locating holes in the running plate and a spacer gauge whittled from a scrap of paxolin.
This was then soldered in place clamping the handrail between some jaws of titanium tweezers (they don’t take solder) and soldered in place from underneath. Any excess solder and wire was simply filed away.

Finally, a picture of the prototype for comparison. 

Tim

[Tim Watson]

Turning attention to the cab spectacle e on the NER 4-6-2 class, I have put in the quarter light separator bar within the window frame. This was made from brass strip let in to a notch cut in the spectacle plate itself with a large piercing saw blade.



The over width strip was then paired down to be flush at the front.  I’m not sure how much lining out was applied to cab fronts on NER engines, but the brass window surrounds will probably just be achieved by scraping the edges of the windows. 

The gap between the firebox and the cab will be covered by a cleading strip. 

The steel cab roof has also now been fitted, making for a suitably rigid structure.  Does anyone have any details of the cab roof ventilators on these Raven cabs?


Tim

[Tim Watson]

After 2.5 days at Missenden Railway Modeller’s summer school, the Raven 4-6-2 class now has a completed cab roof and front buffer beam. 

After massively zooming in on the GA drawings, I decided that the cab ventilator on the cab roof would have been a semi-internal sliding variety. 
The front buffer beam was drilled out, being soldered to some sacrificial brass angle to ease holding in the vice. 
It had a very significant pair of cut-away to avoid platform faces with the side swing of the engine front end. 

I have now worked out how to make the smokebox front, which will probably be the next job. 

Tim

[Tim Watson]

The Skittle Alley had a very attractive smokebox door and fittings, with a clearly separate front to the smokebox itself from the main barrel. 

The method of construction is clearly visible from the drawing. 

The assembly was therefore made in two pieces, with the smokebox door a plug fit into the front ring. 

The front ring was turned using a shellac chuck. This entails holding a blank for the ring on a brass faceplate using hot shellac to lock it into place.  The brass plate is heated with a flame, a drop of shellac smeared onto it and the heated chuck lowered into it, roughly centred until it cools down. 

Here the graver has started to define the ring more clearly. 

A plug, the same diameter as the smokebox door, was used to check for the precise opening size. The seating ring for the door was carved into the front of the brass ring. My Raven pacific, 2400, always had a painted ring and so it was made from brass, otherwise the front plate would have been steel. Once the ring had been made, it was further thinned down to 0.3mm thickness by hand grinding on carborundum paper. It was then cemented to some tufnol sheet to allow holes to be drilled for the top handrail knob and lamp iron.  The loco feature two steps on the smokebox ring. These were made at this stage from some filed down brass angle strip, with both made from one piece, with a rebate filed into the base to clear the raised door seating ring. The scratched line is a witness mark to show the orientation of the step strip. 

The strip was sweated into place and the excess removed with a fine diamond cutting disc. 

The steps were dressed with fine escapement files, protecting the brass underneath from errant filing with some shim steel sheet. 

The smokebox door was turned from nickel silver bar with a 1.6mm spigot to locate and centre within the main smokebox. 
The subtle shape has required quite a careful degree of accuracy in turning and fitting, but assembly should be straightforward as it all self-locates. 

The next job will be the door fittings. Of course, a clever etch designer could have made the smokebox ring with a few clicks of a mouse…but fun to use a shellac chuck, all the same.

Tim

[greenglade]

Lovely work as per usual Tim...

Pete

[Tim Watson]

The facial surgery on the Raven 4-6-2 class continues with the hinges and door straps. Getting these parallel and in the correct place is challenging, but there are dodges that can make the process simpler.

A piece of steel shim was stuck to paxolin sheet with super glue to make it easier to cut out the door straps with a fine piercing saw. 

Having cut out and filed the straps the exposed hinge ends were bent over the hinge pin, a central saw cut represents the top and bottom of each hinge. The hinge pin was then soldered in place with high melting point soft solder. 

The steel shim was separated from the paxolin using a scalpel blade and notched on the fit surface at the ends of the straps with a piercing saw. The square steel on the left acts as a handle.

The door and straps were tinned, held in place with a clamp and ceramic tweezers, heated up with a very hot iron and lots of flux to fuse the components together. Using nickel silver for the door made it easier to solder and allows the centre boss to be polished as bright steel. 

The sacrificial handle was removed by fatiguing around the saw cut; bending it backwards and forwards until it snapped off. 

The little door knob was added by drilling a 0.2mm diameter hill and a short length of nickel silver wire. The next job will be the central handle, lever and lamp iron. 

A slight modification to the door sealing ring was, I think, worth it. 

Tim

[Atlantic 3279]

Even with the dodges and aids employed, I still think it's remarkable work in that scale.

[Tim Watson]

The final components for the door were the dart spindle, round tightening handle and positioning handle. The round handle and spindle were turned as one (actually from an old carbon steel dental bur). Forming the handle and Initial reduction of the spindle was by using a graver but finishing to 0.3mm diameter was by careful use of a file.
https://youtube.com/shorts/kX-HfopfHAM? ... jq_6kHN3Cl
The handle was made from steel shim and filed to give a tapered round section.

The assembly has been temporarily fixed in place with contact adhesive.

The top lamp iron will be incorporated into the handrail knob as it would be too vulnerable in isolation.

Boiler fittings will probably follow; when these are made the whole lot will be permanently fixed with 24hr epoxy resin.


Tim

[manna]

G'Day Gents

The engine now has a Face, Lovely work, amazing in such a small scale.

manna

[john coffin]

Honestly, some of you are a little meagre with your praise. Tim's work is amazing and would be in any scale, it is just more impressive because it is so small.

Paul

[jwealleans]

This is one place the forum could do with a 'Like' or 'We Are Not Worthy' button. We all know the man is creating things a fraction of the width of a human hair and then putting rivets on them, but it feels superfluous to post "outstanding modelling" after every little marvel he puts up.

[Horsetan]

My only surprise is that the smokebox door doesn't open, and there isn't a blastpipe and visible tubeplate behind it....

[Tim Watson]

Thank you all for the kind comments. The advent of phone cameras allows the recording of how to make things: this is really what I try to show with these posts.

Tim

[Tim Watson]

After 50 years of making 2mm scale locos you would think I would now know how to make a chimney…Third time lucky with the Raven 4-6-2 class! Details of turning were covered four years ago when I made the GC 9P. 

The chimney was roughed out, the upper shape refined and then parted off leaving a base from which to file the saddle. A tapered plug mandrel (to match the chimney internal taper) was then made to hold the chimney from the top down - secured with a little loctite. In the background are the two chimneys that were not up to scratch.

The underside was filed concave and then the diameter made exactly correct by using a slightly undersized drill shank wrapped in quite coarse carborundum at the smokebox barrel diameter running the saddle along the paper & side to side. 

The chimney is actually very small at only 2mm tall.

The dome was easier.



Tim

[Jim de Griz]

The chimney is actually very small at only 2mm tall.

I love watching your A2 come together, but this comment really highlights how impressive your craftmanship is. The zoomed in photos almost hide just how incredibly precise your work is!

Jim de Griz