G3 0-4-4T 'Project' based

[jamiepage]

Some bits of the smokebox have been made,most of which will be a fabrication from simple machined shapes. Currently awaiting a lump of cored bronze for the smokebox proper, but the rear ring and saddle have been machined.


The saddle will be bolted then silver soldered to the smokebox itself, the fabrication then being milled away underneath as necessary to allow it to sit down snugly over the cylinder/ steamchest.

The rear ring is machined , from the left, to push into the smokebox proper, a raised decorative brass banding for smokebox rear, a land to take boiler cladding, then finally an extension to meet a G1 Project boiler which will slide/ push fit in..

The smokebox door was turned from an old casting. Much larger than required, it turned down well enough stuck with double sided tape to a mandrel and a live centre holding it in position. Unfortunately, some blow holes appeared and which still show so will need filling.
The boss was turned as an integral part of the door.
Slots were milled to take pre- drilled and partially shaped hinges.


Silver soldered in place and cleaned up, rivets etc were added to finish, then it was tried for size in the embossed smokebox front.


(Yes, these three embossed rivets were on the wrong side.) ^

 

[jamiepage]

The piece of cored bronze was bored and machined to produce a smokebox ring with 2mm thick barrel and doorplate, then silver soldered to the saddle.
5ba screws kept the two in aligment through the soldering process, after which a significant part of the saddle was milled away to let the assembly fit snugly over the cylinder/ steamchest.

The rear ring will be secured, and then relieved to fit over the valve gland, once a door locking bar etc have been riveted to the front.

The front overlay was propped up to give a good idea of the final look.


Rivet lines on the front overlay show how the original smokebox was waisted in to allow room for overhung front springs.
I haven't attempted to reproduce that shape, but the simplified more angular saddle will be hidden in the gloom behind cosmetic frames (outboard of the functional frames) and wheel arches.
Cosmetic springs plus sanding gear etc should camouflage the subterfuge enough I hope.
The front cylinder cover will also hide behind front plating.

Front overlay (and a wrapper) will be held in place on the smokebox with a few rivets, but I may experiment with JB Weld to hold it flat and aligned before riveting. It is apparently 'high temperature' resistant but I'll do some experiments before committing to the model. Glue doesn't quite seem the done thing, nor is it really necessary, but it may make riveting easier- just so long as it doesn't then melt on steaming up.
Has anyone used it in a hot environment? I do recall reading about it being used to fill a blow hole on the bore of a cylinder. Mind you, I don't recall then reading whether it actually worked or not.

 

[jamiepage]

Couldn't bring myself to use glue in the end so the front overlay was riveted in place, assisted by a couple of 12ba screws. The screws were used near the bottom and held all in place while various rivets were squeezed in and dressed flush. The roundheaded screws (and a couple of adjacent rivets) will disappear behind footplating.


On a roll (ho, ho), the wrapper was embossed then rolled to diameter and slid into position.


Loosely positioned for the moment, a couple of rivets, low down on either side, will hold it in place. The chimney/ blastpipe will do likewise.

Rear ring eased away around the steamchest, and the job's just about finished. As mentioned before, a G1 'Project' type boiler will slide into the rear and cladding will sit on the lip, butting up to the smokebox wrapper/ ring. There will be plenty of room for insulation.

 

[geoff_nicholls]

sorry if this has been asked before, but what tool did you use for embossing the rivets?

 

[jamiepage]

A GW Rivet tool, the Heavy Duty version.
'Standard punch' and '3/64 anvil' were used from the supplied punch and anvils .
On .018/ .022 NS, the dummy heads are very slightly smaller than, but close in appearance to 1/32 rivet heads. (See the three rivet heads nearest the lower door rim. The centre embossed head was drilled out and replaced with a 1/32 rivet during construction.)

 

[Jon Nazareth]

Jamie
Could you tell me, please, how did you make up and bore the front overlay ring? There is something like this on the Sterling and it would be good to get an idea.

Jon

 

[jamiepage]

Jon,
Front plate was cut from .022 NS on the pantograph miller then riveted to the front face of the main smokebox piece.
It was simple to cut a x2 template from thin plastikard using an Olfa compass- like cutter for the round bits. A lot easier than fettling the metal.
I would be happy to cut yours for you if you wished.
Yours
Jamie

 

[Jon Nazareth]

Jamie
That's very kind of you and I will bear it in mind.

Regards
Jon

 

[jamiepage]

Chimney, combined liner/ petticoat and shaped spacer were machined up.


The petticoat goes up through a 16mm hole carefully bored in the smokebox, sandwiching the shaped spacer. It's not obvious from the photo but it is threaded along the lower half and screws into a threaded portion in the chimney. The liner fits snugly into the chimney bore and is dimensioned internally (bore and length) with 1:3 and 1:6 draughting angles in mind.


These bits were enjoyable to turn up and the assembly is quite strong- the snug liner adds purchase.

It all sits nicely square, although I've just noticed the handrail holes are far too high. Which is a bit annoying,; they will need tapping/ filling and repositioning. That's for another day though. Bother.
The capuchon dates the model to number 15's appearance just before grouping (as do the bottle guide buffers actually).

 

[Jon Nazareth]

Jamie
That's a brilliant looking smokebox and that chimney, what a fit!!

Could you tell me, please, where did you buy the rivet embossing tool?

Jon

 

[jamiepage]

Jon,
Thank you very much. I'll let the machine tools take any credit for fit, although dressing the flare was a Dremel job.
Riveter came from GW Models- their Heavy Duty version.
No email address, but I called 01903 767231. It used to be, may still be, advertised in MRJ.

 

[oldravendale]

Yep, George is still about. I bought a heavy duty riveter in 2015 - rather overkill for 7mm but the travelling tables are works of art and allow pretty much any frequency and pattern of rivets. He was at Reading in December (in fact that is one of the exhibitions he normally attends) and we had a chat. He's considering retirement so it may well be worth giving him a call sooner rather than later.

Brian

 

[jamiepage]

Jon,
Here's a quick snap to show what you get.

 

[Jon Nazareth]

Jamie
I hate to say this but, I've got one of those ! I recognised the phone number as it's the next code going East from here, but not the name of the company, must be something to do with my age. I didn't know that he did two versions, though, I'll have to et mine out and have a look at it.

Jon

 

[oldravendale]

He actually does three. But most of us will probably not be interested in the entry level one, although I have one and it's great for half etched rivets on kit etches where no table is required.

B

 

[jamiepage]

I'm sure it will come as no surprise to most on here, but even for G3 the GW Heavy Duty rivet tool really is superb.
It is expecting a lot to accommodate G3; although the prototype is small, the platework for tanks and bunker still represent reasonably substantial pieces of material and it took a certain sequence to achieve.


Once the x axis had been adjusted, it was possible to remove, re clamp and continue a line of rivets beyond that possible at a single setting. (An error of less than a degree did show itself on a long run 'straight from the box', but playing about with a spare blank allowed it to be reset accurately).

Once rivet counting from photographs had been converted into appropriate pitches, and start points marked on the blanks, it really was simply a question of twiddling the handles and embossing away.


Thoroughly recommended.

 

[Jon Nazareth]

Jamie
I'll have to have a look at my version to see if it is of the heavier variety.

Jon

 

[jamiepage]

Jon,
The work holding jaw is iro 6 in. long on the Heavy version.

And bent to finish.

I reversed the top plate then filed a curve on one tongue of a Hold & Fold tool. A stop was also attached to the tool from thin plasticard to act as a depth stop for the blanks. (Actually, twice. The bunker returns are deeper than those on the tank sides).
A couple of practice bends allowed the stops to be adjusted accurately and, with a bit of trepidation, the pieces were slotted in and bent up. I had assumed some kind of soft packing would have been required to protect the rivets, but the practice pieces suggested otherwise so I didn't bother.
There is a little flattening of the radius apparent in the photo shadowing, and some packing between rivet lines may have eradicated that, but the distortion is very slight, so I'm happy enough. It will dress out- and be covered by a vertical hand rail eventually.

 

[Jon Nazareth]

Jamie
I've measured my rivet forming wotsit and it's nowhere near 6" long so, I must assume I have the medium version.

Jon

 

[Scale7JB]

The tanks are lovely!

JB.