NSW 'B' class mogul

[David]

Back to the air pump for a bit of plumbing.

The governor casting requires a few holes drilled and an extra fitting soldered to it. The casting isn't the easiest thing to hold so I made a split bush to clamp on the spigot that goes into the pump inlet. There is no indication of the centre of the boss I'm drilling into so I used the tail end of a 4mm drill to get an idea of where it was. 1.2, 1.6, and 2.5 mm holes were required in various places.



The 1.2mm hole went onto the 'front' where a 10BA nut and 1.2mm brass wire was soft soldered on. I would have silver soldered but I was sure I'd melt the wire. I have no idea what this pipe was for, but it's there on the photo of the real one.

I also made the pipe for the lubricator, the air inlet pipe, and drilled holes in the running board to secure the air box and outlet pipe. The air box needs 4 feet yet.

[David]

I've made the pump air cylinder outlet pipe that comes out of the boss on the right hand side of the cylinder above. I might make another because it was made from 5/32 copper pipe so it deformed a bit where a sharp bend was required. I also made the hole for the stud at the bottom of the air box longer because it's sitting wonky as can be seen above.

I also made another bracket and lubricator for the front of the smokebox, and made the same mistake with the bracket as before, trying to trim it with the bandsaw and mangling it. As soon as it happened, I remembered doing that to the other one.

Today I modified the cylinder drain lever to add a kink. Because the boiler is too long the lever hits the dummy backhead at the front of its travel. I marked the lever level with the top of the frames, cut it, filed it a bit to add the angle and silver soldered it back together with a 1.6mm brass shim in there to make up for the saw cut. The slot in the cab floor for the lever will have to be made longer but I won't know by how much until I have the dummy backhead back on.



Then I tried to put the boiler back in the frames and smokebox and it wouldn't go. Something else I did after taking the boiler wrapper off was adding a couple of dummy cladding screws that were missing - one of them at the front. This was now fouling the steel ring riveted onto the back of the smokebox.

I milled clearance into the ring and of course the slot had to go right where one of the 4 rivets fixing the ring to the smokebox is! It took 3 goes to get the slot wide enough to be able to put the boiler in the smokebox.

The parallel is to get the smokebox co-linear with the T slots, the sash clamp is to stop the ring singing while it was being cut.



You may be able to make out the rivet that has been cut away.



I also found the bolts holding the chimney on a bit difficult to get out and back in and was worried about stripping them so I drilled the holes in the base of the chimney 1.8mm and ran a tap through the holes in the smokebox again with the chimney in place to free things up. Much better now.

[David]

It took me a few years to figure out how I was going to make this bit without having to shape it by hand, but the solution arrived in mind last night so here's the lengths I'll go to to avoid manually shaping things! It could have been sillier - I could have done it on the CNC mill!

The bracket is 15mm x 3.5mm with a couple of 10BA holes. The curves were cut by nibbling away at them with an 8mm endmill but I decided they were too shallow so finished them with a 4mm endmill.












I glued the port hole rims into the cab sides, the fire door ring (5th attempt), and the whistle nut on with strong Araldite yesterday. I was going to use a solid copper bit to try and solder the door ring in again without buckling the dummy backhead and unsoldering the wrapper but I can't find the bit. It's not in the drawer it should be with its big brother... no idea what I did with it after using it to add the filler/solder around the curved front of the firebox cladding.

I had another go at getting the front of the reversing screw bracket to sit down too. Plus it was quite dirty with old flux in corners and I couldn't get it clean. I felt it go down after the silver solder had melted and thought I had it this time, but I didn't. After a while in the phosphoric acid to get rid of all the flux, it's still not all the way down. And the steel is now quite 'weathered' from the acid. Oh well. I guess that part's just never going to be quite right. I have a go at it about once a year.

[Jim]

You are making good steady progress David and in the process producing a very fine and detailed model. You should be very happy even if there have been some hiccups along the way but don't worry we all have them.

Jim

[David]

More remedial work today.

The dummy backhead and its fittings have been given a thorough wash in hot soapy water to try and rinse or and/or/ neutralise the bakers fluid and stop the next lot of steel 10BA screws rusting in. I also opened out all the clearance holes of the detail parts to cater to the fact the threaded holes moved slightly when the rusty screws were drilled out and the holes retapped.

Then I started to put the cab front and sides together and noticed some 3/32 rivet holes need to be drilled through the backing angle, and that the rivets that were there had squashed heads. So they had to come out which was easy for one and not for the other. While putting things back together I found one of the curved angles was loose so I heated it up and took it off and found there was almost no solder behind it. It had all been sucked under the bass angle. So not only did it cause a lot of rust, it didn't even do it's job. I'll try Araldite next time.

So we're still taking backwards steps!

[mugbuilder]

Use 956 flux

[David]

I've been working away at the cab roof for a few weeks. Mistakes were made. There was one I thought I could fix relatively easily - the roof being too long - but after thinking about it, it would mean shaving 2mm off the rear of the roof, redrilling the rear batten holes, and remaking side battens and drilling new holes for them. So I don't think I'll bother! I did manage to break a good 10BA tap in the roof and it took 3 carbide PCB drills and a diamond burr to get it out.

The front and rear valances were cut on the CNC from 0.7mm steel. This is how I soft soldered them onto the brass strips. The white-out is to stop the solder going where it shouldn't and also to try to stop the bakers flux from wicking under the angles in case it got that far.



They turned out pretty well. If I'd thought ahead and made the cab front and roof a constant radius curve they'd be even better. As it is they don't fit the profile all that well but it will do. The little clamp was one I made to hold the battens in place while spotting through their holes. A few more would have been good but I got bored just making the one.

[David]

I wasn't happy with a nearly 3mm overhang of the roof over the back or front of the sides so used this sketchy setup to trim it back. The parallels are to align it to the table and wood blocks are holding it down. The trimming almost got rid of the old end batten holes but not quite. But once the batten and end valance are on you can't see the remnants in the gap and they will be covered with fabric too.



Despite the fact it seems to be the same length on either side it's still got a gap when on the loco on one side. No idea why. All the parts seem to be the right size.

This means I need to figure out how to make the side battens on top look good - even rivet spacing at each end - because that's now gone. With luck I won't have to fill the old holes but I'll have to see how close the new ones will be to the old.

Months ago I'd drilled and tapped holes in the angles that are under the roof and go between the cab sides for the 10BA bolts that hold the roof on. Of course they're in the wrong place now so had to be redone. The weird fit of the roof caused a couple of them to go in the wrong place a 2nd time so they'll have to be filled and done *again*.

I've bought some fabric to put on top and to make the curtains from. I tried Gorilla contact adhesive on a scrap of steel and it was pretty hopeless, the fabric could be peeled off with minimal resistance. All those battens will hold it down anyway but it should still be glued a bit better than the test.

[David]

Roof is almost finished, makes the loco look better. Waiting on some 3/64 rivets and then need to put fake planks on the underside.

I added the control spindles for the fake injector steam valves and managed to get both of them about 1mm out of line towards the outside of the cab. This was lucky because I could make spacing washers to put behind the flange on the firebox wrapper so the spindles are straight. I cannot spot where holes in the spectacle plate need to go. Both the handrails are out of line too, one of them so badly I had to fill the hole and move it about 5mm.

[Jim]

Looking great David.

Jim

[David]

It's been a while but there has been some progress. Mugbuilder donated some 1.6mm brass wire to the cause with the comment there was now no excuse for me to not have the dummy oil lines done. So I have 3 of the 4 fitted. I still need to bend up the inlet steam pipe for the air pump - I did one (or two) but wasn't happy with them and when I tried to straighten the 2.4mm 2% silver solder rod I was using it snapped. It also snapped when I tried to get a bend to 90deg. Very brittle. I have a tobin bronze rod now and hope that will be easier. I wanted to use steel but would have to buy 1kg of it.

The little dummy steam valve took a very long time and much faffing about because I made it to the drawing without taking into account the fact my firebox is so wide. I had to cut the stem and then make a spacer to get it to the right place.

[David]

A few more dummy pipes.



And a thing to hold the dome in place. The dish screws onto the top of the pop safety valve hidden in the dome, and what I assume is a dummy safety valve body screws into it. The steam escapes through the holes you can see one of.



In contradiction to what I said on the recent dimensioning thread, this piece was done with end-to-end dimensions! I haven't bothered to check how close I got. It was a bit of a challenge figuring out how far to move the grooving tool each time, taking into account increasing or reducing diameters. Jo Pi and Mr Crispin show how much math is involved in real machining but even simple things like this have a lot of arithmetic and the calculator and scrap of paper were both in play!

[barlowworks]

Hi David

This is slowly turning into an exceptional locomotive..I wouldn’t call it beautiful but definitely exceptional. Keep up the good work.

Mike

[David]

LOL, thanks Mike :) Obv it's a copy of the ones mugbuilder made so the design and all the detail is his work. The only places I've made anything like a deviation was the air pump and dummy clacks where I had good photos and for the clacks a drawing and wanted to go all-out on them.

These dummy pipes are proving tricky because (a) bending pipes in the right place is difficult and (b) the firebox is so much taller and wider than designed nothing goes where it should. But it's close now.

I could really use another 2mm of length on the weighshaft - the reversing lever is rubbing on all those pipes. Still trying to see if there's an easy-ish way to do that or just live with the paint getting rubbed off.

[barlowworks]

One of the reasons I chose a Britannia as a first build was the number of build threads available and the number of Britannia’s out there. You just have to work to standards and levels of detail you are happy with, you certainly seem to be doing that.

Mike

[Jim]

May 3, 2021 12:13:52 GMT barlowworks said:

One of the reasons I chose a Britannia as a first build was the number of build threads available and the number of Britannia’s out there. You just have to work to standards and levels of detail you are happy with, you certainly seem to be doing that.

Mike

I agree totally with Mike's comments regarding the standards and level of detail you're happy with.

It's important to keep in mind that it's your model and your creation and to my mind you're creating a great model of a B class mogul and to a very fine level of detail and craftsmanship.

Keep up the good work David.

Jim

[mugbuilder]

Good job Dave. I will be at the club tomorrow ang you can return my 9/16-26 tap then.
Barry.

[David]

This afternoon/evening was spent on the dummy cylinder drain crank.

On the prototype the right-hand-side handrail is hollow with the cylinder drain operating rod inside it. The crank goes up into the handrail. I milled a slot into the bottom of the handrail. The 'bottom' was gauged by running a permanent marker along the underside while the handrail was in place. The slot is about 2mm wide in a 1/8 rod to give some room for the crank to move about in case the slot isn't right on centre.




The crank was made on the Tormach.

[suctionhose]

What's the latest David? So close now...

[David]

Thanks for checking in Ross!

The latest is that I finally have a job I really enjoy so I've been doing that instead! I'm working for the state government in a small team in doing ag-tech stuff and it's been a lot of fun finally having team mates I can see, interesting work to do, and the office is at an ag research centre on the edge of town. It's the best job I've had in 20 years. The pay is rubbish, I lost an awesome health fund, the contract might run out mid next year - nothing about it was a good idea except I was dying where I was and now I look forward to going to work each day. It's given me a ton of energy back for learning new computer things, and I've learned more in 4 months than I did in the previous 15 years. I'm slowly catching up on all the stuff I couldn't use before due to a stifled work environment, and didn't have the enthusiasm to learn out of hours because I knew I couldn't use it.

This came about because my wife went back to uni a couple of years ago to get a psychology degree. That spurred me on to try yet again to sort out the comp sci degree I never seem to be able to finish as a last ditch effort to get myself out of the hole I was in. I've done about 2.5 degrees worth of subjects over the decades. The course coordinator did an excellent job in somehow shaving things down to 4 subjects to be done so I did that last year. Two of the subjects were a project and I said I wanted to do something with a local organisation, preferably with some practical aspect to it. He pointed me to my current boss and I treated the subjects as an 8 month interview. A further stroke of luck was that there was no job going there that I could afford to take, then the guy who's job I have now decided he wanted to go back to being a free agent contractor and left, opening up a job I could just afford the pay cut for. There were heaps of applicants but I got through in the end so really pleased with how the 12 month plan came together, including the dumb luck of a job appearing at exactly the right time where there was none before. I didn't know any jobs were going at all, it was one of my interstate uni team-mates who alerted me to the fact. So that's my allocation of luck used up for quite a while I'd say.

As far as the B class is concerned:

I made the dummy ashpan crank and operating rod.

I made the rod that goes from the crank that slot in the handrail was cut for through the running board. Despite endless care in marking and measuring where the hole should be, it is in the wrong place and the rod is crooked, which annoys me no end.

I had to make a new bolt and spacing washer to bring the reversing reach rod out 3mm where it fits the weighshaft so it doesn't foul the water inlet pipe for the boiler, and also have to move a clip that holds the dummy oil pipes in place because the nut on the back of this bolt also fouled the clip. The dome isn't sitting right yet either but I'm too scared to try and fix it because I'll probably make it worse. The water pipes on the side of the boiler still look terrible but I'm not redoing them. It's as I feared - the more of this freehanding rubbish I have to do the worse the loco looks.

What I *should* do is to take the bodywork and boiler off so I can fit a washdown plug and the blowdown valve (which I know will leak but don't want to make a new spindle for, because I'll also have to grind a tool to cut it!), put it all back together with all the plumbing and test the whole circuit on air, take it apart to fix the problems and leaks, repeat ad-nauseam.

Then I take it all apart AGAIN and clean it and either have to botch up a paint job or find someone to pay to do it for me.

I just don't have it in me for now to do any of that.

I've done a few jobs for my father-in-laws latest project and that's enough shed time for me. We're moving out next week for about 12 months while we overcapitalise on a house renovation (guess where my 20 years worth of long service leave is going? It's not on a holiday and I'm pretty cranky about that) and the workshop's not coming with us so play will stop. With luck 12 months off will give me some puff back.

The red loco has had a few outings, including it's first run on foreign metals in decades, but has been steaming very dully. Or has been fired very dully - probably more the case! And the roof broke off. I haven't fixed that either. It's easier to drive without the rear sheet of the cab anyway.