Smokebox dimensions

Have been working out dimensions for the chimney liner and blastpipe/blower arrangement. If you stick to the 1 in 3 and 1 in 6 rules (see JvR's diagram above) it presents a challenge with such a short protrusion of the chimney over the top of the smokebox. With a 13mm ID liner (i.e. a bit of radiator pipe!) you end up with needing to put the exhaust jet underneath the smokebox which clearly isn't practical. Lining the inside of the chimney to 10mm means that you can just about get the exhaust into the smokebox as it can sit 60mm below the top edge of the chimney. I might ask a friend with a G1MRC Britannia how it works on their one as they all seem to steam very well. Perhaps it uses some kind of multiple-jet arrangement? Once I have this sorted I can get cracking with building a proper smokebox and try the boiler on the blower.

Boiler & Burner Test

Enjoyed a nice Sunday lunch and then made up a temporary smokebox with a piece of pipe silver soldered to a flat piece of brass to cap the end. Stuffed the gaps with sheet insulation material to 'seal' it as best i could. Fired it up and despite most (not all, but nearly) of the fittings leaking profusely, the boiler itself was water-tight and the first safety valve lifted off at about 50psi. I have both a large pop valve and an Accucraft valve fitted at present. Pleased with the test and delighted the boiler makes steam ok. Next job - get the chassis running!

Boiler Fittings

Have spent some time on the boiler/burner system recently, hoping to test that it can work effectively in a Stephenson's configuration, with a draught from the exhaust/blower required. The burner is a similar design to the G1MRA Dee design, scaled-up with an additional 'up-comer' for secondary air.

Having tested the burner in an open space I have now moved on to fitting the boiler so that it can be tested. I have had to re-tap some of the bushes as they were all 7/32" with 40TPI threads which made it difficult to fit 'off the shelf' components.

I found that Reeves do a nice clack valve with a  7/32” 40TPI thread so I have bought that and fitted to the boiler. I have also run a 5.5mm drill through the bushings for the water gauge and the pressure gauge and successfully re-tapped these to ¼” 40TPI and fitted the pressure gauge and just need to cut the glass for the water gauge then that can be fitted too. Next job is to turn two adapters so I can fit Accucraft safety valves (these have a metric 5mm fine thread). I am also making a steam manifold to screw into the one remaining bush so that I can then fit a blower and regulator.

Will have to flush the boiler after all that tapping as I am sure it will be full of bits of bronze...

Burner

Having had a couple of people take a look at the boiler I have for the Britannia, I have decided not to go for closed flue firing and instead use the Stephenson's approach with a blower. Seeing as no-one else has the same boiler and firing method I am somewhat starting from scratch here, however, I have effectively made a much larger version of the Dee burner, with two secondary air holes. Copper sheet and tube, silver soldered throughout. Ceramic grate at the top. Finished this evening and yet to test it!

Tender side frames and dragbox

Tender side frames - these are the third set! I drew these in a CAD program and included holes for brass rivets. They are bolted to the dragbox and buffer beam to allow for easy removal/maintenance

Smokebox attempt 2

Was looking at this morning's attempt and scratching my head trying to work out why it looked wrong.... Then realised the chimney drilling is in the wrong place! I drilled it as per the MEL drawings but holding it up against the Skinley drawing or a photo shows it is wrong. Have started on attempt 2!

A start on the smokebox

Made a start on the smokebox, turned a piece of 2 1/4 to length and started the drilling. Will leave the lubricator drilling for now whilst I ponder where to put it.

Back on track

Britannia building has been on pause until now as I have had to move the workshop. Getting back up to speed now and thanks to a kind soul in Australia I have a mass of photos and drawings to assist in progressing the Britannia. Furthermore, I have decided to go for the 'cheat' option on the cylinders and axle pump and bought these from MEL.

A lesson learned is that parts need to be preserved carefully... thankfully a small ultrasonic cleaner from Maplin does a fine job of dealing with surface rust.

Tender frames - An alternative

I travelled to Woking yesterday for the G1MRA annual meeting and enjoyed wandering around the hall and seeing the layoyts and locos running. Even the smell of meths in the hall was oddly appealing!



The trade stands were also excellent, I picked up a number of bits for the both the Dee and Britannia, mostly things like 90 degree pipe unions for the tender, Dee buffers and dome, coupling hooks, etc. I also saw Malcolm and his Britannia there on the Model Engineers Laser stand. Malcolm has a well-progressed chassis with all the cylinders, motion etc complete and a cab and smokebox also. Looks great and inspiration to get a move on with my one! Interestingly, he also had a new kit for the tender chassis, a slot-together and soft-solder one for a very reasonable 17 quid. Now, I already have a tender chassis, but for 17 quid it would have been silly not to buy one in case i end up wrecking my one again. I think I have spent around 30 hours on my chassis already. Pic below is of the MEL one slotted together and held with bolts at this stage... it took less than one hour to separate the bits, file the little tabs smooth and slot together. Not soldered yet but shows how much time these kits can save!



Not sure if I will use it yet. I would need to make new bearings for the wheels as the holes are slightly larger on the tender sides on the kit. I may butcher it and take the part that holds the tubes (water/gas) under the tender and also two of the stretchers and use those with my current chassis.

I also met Dick Moger, who was one of the pioneers of the Dee design I mentioned in an earlier post. I have made some progress with the Dee and learnt a lot along the way that will help me immensely in putting the Britannia together. Piccy of some of the parts follows:

Tender frames

So, managed to drill and tap four holes without wrecking the new buffer beam. Still need to add rivet detail to the buffer beam, mill away the unwanted material on the back and drill and mill the slot for the coupling hook.



I have also started to drill holes in the tender frames to add rivet detail. The tender tank had over 200 rivets to add, I think the frames have around 50 per side. I drilled 10 earlier (after taking the pic above) and am convinced enough to do the rest... I also discovered that 'Wagon & Carriage Works' were happy to sell whitemetal castings for the tender water seives which is great news as it will save time trying to mill them myself from solid.

Tender

Managed to mess up the drag and buffer beams last month whilst trying to drill and tap the holes for the fixings to the frames. (broke a drill bit in one and a tap in the other!)

Had a hectic couple of months recently but managed to get an hour in the shed today and make a good start on a new rear buffer beam.

4-Jaw and a Hacksaw

Finished the axleboxes today, still need to sort some springs out but otherwise the front bogie is now pretty much finished, shown here resting on top of a machined block of brass that will eventually be a Dee cylinder block!



Busy week ahead but will get back to the tender in due course.

Axleboxes and more on rivets

An interesting week, I have soldered four of the tender parts together and will be soldering the remainder when the present gusty weather conditions have passed (it gets a bit tedious when the wind blows out your blowtorch every 5 seconds).

So pleased was I with the tender sides that I sent Malcolm at Model Engineers Laser a picture and commented that the riveting process was easy enough and in my view there was no need for laser spotting the rivets or etching. Anyway, within a few hours I had an e-mail in my inbox from Roger Thornber. I tried to explain to the wife that a 'newbie' to Gauge 1 getting an e-mail from Roger is a bit like someone who has just started going to church getting an e-mail from Jesus. Anyway, Roger had sent a picture of his etched 8F tender sides which looked stunning.

For those who come across this blog and want to repeat my approach to the rivets, it basically involved the Metalsmith riveter (see links), a photocopy of some scale drawings from PDH (see links!), some slow-setting paper glue (e.g. UHU or Pritt-stick) and a digital caliper! I cut out the photocopy and stuck the copy of the left-hand tender-side face-up to the inside of the right-hand tender side, then before the glue set, I carefully positioned the copy in place using the digital caliper and measuring from the bottom of the tender side to the bottom edge of the rivets, basically sliding the paper on the brass and measuring to ensure that the main horizontal line of rivets was exactly horizontal. Then it was a case of just carefully punching the holes through the marks on the paper. The riveter has a guide built-in also which adds another degree of comfort when doing the horizontal line but it obviously cannot be used on the vertical lines as there is no straight-edge to run against (because the tabs are in the way). To do the other side I peeled off the photocopy I had just used, flipped it over, aligned with the digital caliper as above and punched through the holes in the paper. It’s a bit ‘Blue Peter’ rather than Model Engineering but it works!

I realize that the above method will not work if the paper does not sit perfectly flat on the photocopier (you will get curved lines!) and it also relies on the both the drawing and the laser-cutting to be accurate (which they were). As I mentioned to Malcolm, it took me less than an hour to do both sides so it is quick (in the grand scheme of building a G1 loco) and I think an effective alternative to etching.

Anyway, with the wind postponing any soldering today, I took shelter in the shed and changed the 3-jaw chuck on the lathe for the 4-jaw (remembering to protect the lathe bed first in case i dropped it!) and set about machining the front bogie axleboxes. I hadn't used the 4-jaw before but got to grips with it quickly and was soon getting the hang of centering work and I have made good progress on the axleboxes which i hope to finish tomorrow.

I have also bought a big lump of brass and plan to use this to further refine my 4-jaw lathe skills... I have the G1MRA Dee and Project books and thought that it would make sense if my first attempt at machining cylinders and valve gear was an inside cylinder loco rather than making mistakes on expensive castings (the Dee cylinder block is very small and that volume of brass costs less than pint of beer, not to mention the fact that G1MRA books are excellent and have been described to me as a "great introductory course to model engineering"). This was the round-about excuse I gave the wife anyway for daring to suggest starting on a second engine before completing the first!! She has kindly bought me a boiler, wheels, and a complete Model Engineers Laser Dee platework kit for my 'model engineering course' for my birthday! How I ended up with such a good wife is beyond me, but God bless her nevertheless!

Tender Sides

Some more progress with the tender sides today, finished adding the rivet detail and formed the curves/folds. The picture below isn't great but you get the general idea!



Next steps are to soft solder the tender tank parts together, file off the tabs and add the detail and gas/water fittings. I still have some outstanding work to do on the tender chassis also.

Riveting stuff!

Spent some time trying out the rivet embossing tool from Metalsmith Ltd (see link right) - it is the perfect match for the tender kit from Model Engineers Laser. It's actually a lot quicker that I expected to add the rivet detail. Must remember when I do the other side that the sides are handed...

Tender drag beam

The long-suffering wife allowed me a couple of hours in the shed today and further progress was made on the drag beam for the tender. The drag and buffer beams are the key parts of the tender chassis as they hold the two tender frames together, once have they are finished I will have a proper rolling tender chassis.



All the dimensions for the drag beam are correct, apart from the cut corners at the bottom. Must have made a dodgy imperial/metric conversion somewhere (drawings are imperial, mill is metric). No major problem, just need to take a little more off each corner. Also need to drill and mill the slot in the centre (for the bar that connects loco to tender).

Some piccies

About 6 months along the way now, thought I'd post some piccies...



Still some way to go yet, although I would say that there are lots of bits that have been acquired that are not pictured here, including kits for cab and tender body, crankpins, connecting and coupling rods, cylinder castings.... just awaiting machining/assembling! The picture above reminds me that i need to file down the tabs on the main frames also.



As mentioned before, the boiler looks the business. It could be a while yet before it steams... I have spent around 3 hours over the last couple of days machining the tender drag beam and it is only around half done so far - this is a time consuming business!



Mike at Maccsteam also made the tender tank. Although you can't see it in this picture, the tank extends below the tender baseplate with a trough underneath. It has a number of stays and in many ways is no less complex than a boiler so I was glad when he said he would be able to make it. The tender body needs some folding but looks straightforward enough... the tricky bit will be adding the rivet detail - I stopped counting at 180 rivets when I looked at the drawing!

An update

Long time since the last update! New addition to the family has seen attention focused elsewhere. That said, I think I must be quite unique in that not many people can say that they telephoned from a labour ward in between contractions in early labour to order a rivet embosser tool!! Funny what you remember to do when you are sitting through a 3-day labour!

Additional pair of hands is now with us, mother and baby doing well, mum, dad, grandad, grandma and great-grandma all very happy and proud!!

On the Britannia front, early May I took delivery of the boiler and gas tank. Mike at Maccsteam did a super job. I will post pictures soon.

I gave up on ideas of using the Chester lathe for milling. The vertical slide that Chester supply for the DB7 lathe is not fit for purpose and the support from Chester was sadly woeful! That said, the lathe itself was great value for money so perhaps I should not expect too much! I ordered a Sieg micro mill from Axminster (arrived next day) which I have used to make a new start on the axle boxes for the front bogie. I have also procured further parts for the cylinders from Malcolm at Model Engineers Laser, and some crankpins from Walsall engineering. Not to mention numerous taps, dies, etc.

My priorities over the summer will be something along the lines of:

2. Finish front bogie
3. Finish trailing truck
4. Complete tender chassis
5. Add rivet detail to tender sides and complete tender

Number 1. will of course be the baby!

Tender - Rear buffer beam

Cut out the tender buffer beam this evening from a piece of sheet metal. My metal working skills are generally poor so I cut the piece out slightly oversize with the saw, then clamped it in a vice to a piece of square steel bar so that the oversize part protruded. I then filed down against the square bar to give a straight edge and the correct dimension. A bit of a bodge but it gives the right end result, albeit scuffing up a perfectly good bit of steel bar in the process!

Trailing truck - side piece

Finally silver-soldered the last side piece of the trailing truck this evening, as I write this it's currently pickling in the acid bath.



I've made some enquiries about some of the long lead-time items, specifically the boiler and the nameplates (I've been advised the nameplates could take 4 months). Mike at Maccsteam (see links) can make the boiler and I'm hoping also the gas tank as I don't think my ten-quid B&Q torch pictured above will get enough heat into the work to silver solder it.