NSW 'B' class mogul

[steamer5]

One of the guys used the outside of a dead kitchen toaster, shinny stainless steel, that REALLY blings up your cylinders...….. he did get a lot of ribbing about it


Cheers Kerrin

[David]

I miss having a K&S stockist in town! So useful.

I have some thin brass - perhaps also 0.010" - but I can't see it being much more durable than the aluminium to be honest. I also have some 0.7mm steel like I used for the boiler cladding so there are many options.

[David]

A bit of finishing on the lubricator in the form of a flat milled on the barrel that supports the shaft so I can tighten the nut properly, a washer to take up most of the slack on the outside of the shaft, and started making a lid for it. Then I tested it on the bench and it still works which is good. Hopefully there won't be any leaks along the route when full steam pressure is present. I hate tightening those 1/4x40 brass threads... so easy to strip them. They're all relatively easy to replace aside from the one on the inlet T.

Then I had another go at making the cylinder covers. The aluminium can seemed to be about 0.1mm thick! So I went to the brass sheet which I think was 0.4mm thick and that feels strong enough to me. I bent them around a 25mm brass rod and couldn't get a terribly close fit so I'm hoping the black paint fools the eye. It was pretty scary drilling the little 10BA tapping size holes in the cylinder castings with a pistol drill but I didn't break anything and didn't break through into the cylinder. I had a piece of tape on the drill at 6mm depth. I felt the drill shoot forward at one point which I think was one of the end cover bolt holes because it still seems to be a blind hole.

[Jim]

K&S metals are hard to find here too in fact I suspect they may no longer supply here but there are other sources in the hobby shops such as Precision Metals that are worth checking along with the Craft Section of places like Lincraft and Spotlight, the last two I know of from going shopping with the boss.

Jim

[Jim]

The cladding on the cylinders looks pretty good to me David. I certainly wouldn't complain about it.

Jim

[David]

Thanks Jim, it doesn't look quite so good in person.

We have a Spotlight here so I'll have a look. We don't have any hobby shops anymore. The old Jaycar used to have K&S, Plastruct & Precision Metals plus a lot of Warhammer stuff (so paint) but they went broke, the new Jaycar franchise only lasted a couple of months and never had anything interesting. We have a place that sells football merchandise that took the model railway stuff over but they only have a bit of Hornby stock, no scratchbuilding supplies.

It's a shame Edcon don't stock this stuff. They have round silver steel and brass hex which is a godsend. Flat ground stock prices there are beyond belief.

I would have thought Canberra was big enough to warrant at least one good hobby shop. We were in Sydney last week and visited HobbyCo but short of buying a few of everything I couldn't think what to choose!

[stevep]

I clad my Stanier cylinders using pieces of tinplate out of the side of an old Castrol oil can. (Remember when oil came in metal cans instead of the dreaded plastic?)

Can't remember having any problems with it.

[David]

Tinplate is nice stuff. We can still get square cans of olive oil I think. I had one a few years ago but didn't end up using the tinplate. Really good for soft soldering.

[Jim]

We do actually have a couple of hobby shops. Toy World in Fyshwick is my 'go to' spot. I've also done as Steve suggested and 'reclaimed' tin from biscuit tins etc. Just after Christmas there are lots of sources of tin plate around disguised as tins for biscuits, cakes, lollies etc.

Don't be too hard on yourself David, the cladding on the cylinders looks pretty good to me seen through the harsh eye of the camera.

Jim

[suctionhose]

Jan 24, 2020 7:07:48 GMT suctionhose said:

Talk to James Sanders...

I thought they were his cylinders! Just cladding...oh ok

[David]

Given that's really a 24 class with a saddle tank and no tender perhaps he trying to get more power than us by going for maximum bore dia...

I just noticed I have a 4L tin of wax/grease remover here that I'm getting through at a pretty rapid pace. Whatever it's made of will be nice and clean on the inside surface so I might cut it up when it's empty.

[Roger]

Jan 27, 2020 21:17:36 GMT David said:

Given that's really a 24 class with a saddle tank and no tender perhaps he trying to get more power than us by going for maximum bore dia...

I just noticed I have a 4L tin of wax/grease remover here that I'm getting through at a pretty rapid pace. Whatever it's made of will be nice and clean on the inside surface so I might cut it up when it's empty.

Could you not use Shim Steel which you can get on a roll? Properly primed and painted, it ought to last a very long time. That's what I plan to do. I used the same thing for Boiler Banding.

[David]

I wouldn't know where to buy a roll of shim steel. The brass worked well enough.

The painting of the cylinder covers didn't go so well. Not only did they clank together while still tacky so putting a mark in one but one ended up much flatter than the other.



I stripped the paint off and did it again, it was a bit better the second time. I also painted the lubricator and the screws for the covers and lubricator although of course I forgot to do them on the same day!

I had to open out the oil holes in the con rods, I think the loctite holding the brass caps in blocked them. Lucky I had to put bigger holes in them and then when I tried to clear them of swarf I saw nothing coming out in the bush.

It's back together now other than:

• The dummy leaf springs which I'll leave off until I've given it a test run and proved the lubricator works,
• The guard irons which will need a piece of steel silver soldered to the rear of where the bolt holes are so I can move the holes back a couple of mm. I'm not getting the clearance with bending.
• The forked arm to join the handbrake screw to the brake cross shaft. I had silver soldered this but put it on the wrong way so you could see the machining mistakes so took it off again.
• There's a few dummy brake cylinders to paint and attach but that should be easy.
• A lid for the lubricator.

And here I thought I was almost done under the running boards and between the frames!

It's difficult to show black on black but here it is.





I think I'm seeing some oil seeping out of the steam chests which is really disappointing given I tried to button all that up. Perhaps I didn't do the nuts up enough but I stripped one stud so got a bit gun shy after that.

[Roger]

Hi David,
I bought my Shim Steel from eBay

[David]

Aus eBay is no good for material, the only 0.5mm steel shim I could find was in a tin at about $70 ($48 for the steel, $20 for postage) shipped from the UK. Aus eBay is really only useful for cheap cutters from China. I think our market is so small, postage is so high, the dollar is so weak, only the flood of cheap junk from China is reasonably available to us. Amazon is the same. We call it 'the Australia tax'. I'm sure our NZ cousins find the same thing. I read some amazing story of how difficult it used to be to import machine tools into NZ - it was like they didn't want people making stuff.

I put the weighshaft back in tonight and gave the loco a run on air. It took quite a bit of air to get it to go to start with but it settled down after a while. I didn't want to give it a heap of air and break something so I took it pretty easy. I'm not convinced by it's behaviour when notching up. I know there isn't any expansion working on compressed air but I'm sure it used to be more stable whereas now it seems to race occasionally. That could be due to the weighshaft moving and changing the cutoff itself I guess, I wasn't holding it and didn't have it clamped. But it didn't used to need it. Perhaps driving the oil pump is upsetting it, that's a load that wasn't on it before.

The lubricator isn't all it could be yet. I think the actual mechanism works ok, it's the outlet fittings that have problems.

It didn't work to begin with and I discovered the outlet pipe with the ball for the one way valve had partially unscrewed itself so I'm guessing there was no vacuum in the pump to draw oil in on the upstroke. I tightened it up and bench tested it again and it worked for a while and I eventually saw oil come out of the tail that screws into the inlet T so I attached that to the inlet T.

That caused back pressure in the pipe which started forcing the oil out back near the lubricator because one of those tails wasn't done up very tight - because I'm so worried about stripping the threads.

Then I saw bubbles in the oil tank again and oil leaking down around the outlet somewhere. I'm guessing the original problem has come back but I'd had enough by then so didn't feel like draining the oil and taking the lubricator off again. So I don't yet know if it's a bit of grit stopping the ball sealing or the pipe has unscrewed again, perhaps due to either vibration or as a side-effect of tightening the elbow onto it.

[David]

The oil pump continues to frustrate. I took it off yesterday and when I stopped the outlet with my thumb I saw the oil coming out of where the outlet pipe / check valve joins the pump barrel. That is a difficult nut to do up because the pump barrel just turns in the body when you tighten it up, despite the nut holding the barrel in place which has the same problem, ie not being able to do it up very tight.

In any case I did my best, put some Loctite 567 on the leaking thread, and left it to set overnight because the Loctite tube says don't give it full pressure until it's set.

This morning the pump pretty well locked up. I foolishly tried to free it by force and bent the part the crank runs in open. Probably didn't do the roller clutches any good either.

I took it all apart again. Not easy now it had been forced together so hard. No Loctite had got into the mechanism so that wasn't it. I cleaned it all, bopped the opened part back into shape and gave it some filing for good measure to remove any burrs, filed the 0.25mm or so of the stud protruding through the crank web... put it together again and it still locked. Took it apart again and removed a washer I'd added behind the crank shaft carrier and that finally gave it the clearance it needed to run. At least since this morning because it ran fine until last night as it was.

I can only imagine doing things up more tightly than usual had caused binds to appear so it required more clearance.

I tested it with my thumb again and it tried to push the oil out past my thumb and not out any threads so I put it back on the loco... and masses of air bubbles appeared in the oil tank so the check valve still isn't doing it's job under high pressure (probably less than 50 PSI).

I'm running it with the delivery pipe disconnected from the inlet T to see if it will start pushing oil out with no back pressure. Nothing came out for a very long time, I ended up disconnecting the drive and doing it by hand to speed it up. It finally showed at the end of the delivery pipe.

Now what I feared seems to be the case and the thread where the pipe joins to the inlet T is munged :( The cap I use still works because it has a much greater depth of thread so must still get to the good part but the nut on the nut and tail doesn't have enough thread to get there. I guess I can make a new deeper nut but that involves unsoldering and wasting a tail.

I've tightened it just to the point before it slips loose again and am running it like that. If no air bubbles appear, oil doesn't come out in the wrong places, and the oil level goes down I may see if I can get away to 567 on that thread too.

Not a fan of this part. It's been nothing but trouble since I made it and I have a feeling it's going to continue in that vein as long as it's around. But I can't imagine I'd do a better job if I just remade it and that doesn't solve the problem of the inlet T thread either.

EDIT: And the air bubbles are back.

[Roger]

Hi David,
It's generally not a good sign if you have to do things very tight to get a seal. It usually means there's an underlying problem that isn't being resolved, possibly you're running out of thread before force is being applied to the joint itself. It's probably worth having a really good look at the offending part and seeing if you can figure out why it's not sealing. It might be a simple fix such as changing the thread length.

[David]

I wish I could, easily at least. To fix the male thread I'd have to take the inlet manifold off, unsolder the current threaded part and risk melting the other joints, then solder a new one on. This one has been tricky to do up because the pipe has such a tight bend it tail doesn't line up well with the mating centre drilled part which is why I think the thread got damaged - me trying to make the thread line up the pipe. Just screwing the blind cap on doesn't have that problem.

There is extra male thread the current nut can't reach so the solution might to be make another pipe with a custom nut that has a few mm more thread in it to reach the undamaged stuff. I can make it overlong and keep trimming it back until the tail seats well then put it on the pipe.

I saw a pipe bender Kozo uses in an article in Live Steam magazine last night. It's just a disc with the pipe profile plunged in it's edge and one side milled flat to go against a vise jaw. If I can't get this pipe to behave that might be an option. But the bends are 180deg only about 20mm wide in 3/16 pipe - it's really tight.

None of this explains the air bubbles coming back, and why I don't see them in bench tests when I'm blocking it with my thumb. Surely it can only be the non return valve which is a steel ball seating on an o-ring so I can't see how it wouldn't seal.

Building the valve gear and getting it running was trivial compared to this mongrel. Possibly quicker too given I've sunk more than a week into getting this fitted and still not working.

[Roger]

Sometimes you just have to bite the bullet and take it all apart for a proper repair, even though that's a lot of work. When you've exhausted all of the easy fixes, there aren't many options left.

[mugbuilder]

Jan 31, 2020 9:57:33 GMT David said:

I wish I could, easily at least. To fix the male thread I'd have to take the inlet manifold off, unsolder the current threaded part and risk melting the other joints, then solder a new one on. This one has been tricky to do up because the pipe has such a tight bend it tail doesn't line up well with the mating centre drilled part which is why I think the thread got damaged - me trying to make the thread line up the pipe. Just screwing the blind cap on doesn't have that problem.

There is extra male thread the current nut can't reach so the solution might to be make another pipe with a custom nut that has a few mm more thread in it to reach the undamaged stuff. I can make it overlong and keep trimming it back until the tail seats well then put it on the pipe.

I saw a pipe bender Kozo uses in an article in Live Steam magazine last night. It's just a disc with the pipe profile plunged in it's edge and one side milled flat to go against a vise jaw. If I can't get this pipe to behave that might be an option. But the bends are 180deg only about 20mm wide in 3/16 pipe - it's really tight.

None of this explains the air bubbles coming back, and why I don't see them in bench tests when I'm blocking it with my thumb. Surely it can only be the non return valve which is a steel ball seating on an o-ring so I can't see how it wouldn't seal.

Building the valve gear and getting it running was trivial compared to this mongrel. Possibly quicker too given I've sunk more than a week into getting this fitted and still not working.

David I have made heaps of these pumps and they have all worked well firsr time. If there are bubbles in the oil tank the clack ball is not seating on the 'O' ring which gould be caused by the spring holding it up being to weak . Oil coming out from screwed parts could only be bad fitting of the components. Bring the thing around and i will have a look at it.