NSW 'B' class mogul

[steamer5]

Hi David,
The wrapper is looking great! You are making it look easy.

On the ceramic taps, they last better than washers but still need replacing. Our kitchen sink tap that gets used probably more than all the rest in the house I had to replace the ceramic cartridge after 10 years. Ours were relatively easy to replace, just needed the right size socket. Oh they aren’t cheep either!

Cheers Kerrin

[David]

I made my transfer punches and although the cladding looks okay against the spectacle plate once I'd got the holes in for the safety valves and massaged them around to get the cladding looking about the same on both sides relative to the windows the safeties are off center relative to the cladding's centerline by about 3mm. Thank goodness they seem to be passably in line with the center of the dome and spectacle plate when I put a rule over the centers of the holes in the dome and safeties.

There are so many variables involved - where the bushes are relative to the boiler center line, the symmetry of the boiler, how it sits in the frames, the cladding, the cab... what a nightmare. No idea what is off - could be all of it. I'm a bit stumped - I can't see how the cladding centerline can still look it's line with the split in the spectacle plate, and the safeties seem to be in line with that same split and the dome.

The cutout in the spectacle plate for the boiler is also too wide on the right hand side showing outside the cladding.

I was quite disappointed but am going to live with it and hope I can learn to ignore it. The option is always there to have another go if I find it's too distracting.

If I hadn't already scribed all the lines and drilled all the holes I could have recovered somewhat. The way to go would be to only scribe the line that goes across the top and down the sides because that has the bends in it. The fore/aft lines could have been done and the holes drilled with the wrapper bent up. If I'd done this I could also have had a go at recovering some of the 10mm extra length that has come from somewhere. All useful notes for the other guys!

One of the photos shows how skewed it is. The two holes between the valves should be equidistant each side of the valves. I'll fill and redo them but it shows how far off things are.

At least I know the situation with the reversing screw now. I'll have to come out about another 4mm or so which is also quite a lot. The nut is hard up against the cut-out in the cab, meaning the boss can't go thought, and the boss on the boiler side is pressing against the cladding. There is no space behind the cladding I can get back - it's just because the boiler is so oversized. That's going to look a bit silly with so little spectacle plate left beside it. I'm working myself up to unsoldering the front of the screw bracket again as the screw is too lopsided for my liking.

[mbrown]

Perfectionism in model engineering is a great virtue - but I do think you are being rather hard on yourself. Look at an aerial view of pretty well any full size loco and it is likely the various centre lines will be askew in some aspect or other - especially when it has been taken apart and reassembled for overhaul, received a new boiler ( full size boilers often differed in minor dimensions) and so on. My rule is that, so long as it doesn't stand out like a sore thumb it is likely to be as good as the real thing.

But I do appreciate that some engineers start with mechanical precision as their goal rather than conceptual fidelity to prototype!

It's going to be a beautiful machine....

Malcolm

[ettingtonliam]

Apr 26, 2019 23:31:34 GMT David said:

Thanks for the kind comments.

The photos must be flattering. The 'throatplate' is marginal and the firebox wrapper is looking better than I expected but the bends halfway down the sides are more like creases. There are no reverse bends below that either, I've not managed to make that work yet.

It has turned out better than I expected so far other than the throatplate, but my expectations were rock bottom.

Onto the transfer punches this morning if I can't get 2nd son to come and do his paper run. I also have to check the shower taps, my wife insists they are leaking. They have ceramic valves in them which are meant to last forever and not leak - anyone know about them?

I'm sure a pair of shiny safety valves will be a nice distraction on top.

I don't have rollers so my plan for the barrel wrapper is use a 'rolling pin' when it is on something soft. It will be 0.7mm steel like the firebox wrapper, which bent very easily. Do you think this will work?

I'm not sure you'll be happy with the results of the rolling pin method. The ideal is to use rolls, if you can find someone who'll lend them, or roll it for you. A sheet metal shop would probably do it for the cost of a drink.
If that fails, try this, which I used a few times before making myself a set of rolls:-

Turn a wooden block to the diameter of the boiler, possibly slightly smaller, and slightly longer than the barrel. Make 2 pieces of steel flat about 18" long, with a hole drilled at one end, and screwed to the centre of the block at each end. Then get your rolling pin (not the one from the kitchen, this won't be popular), cut to the same length as the block, and screw to the flats, just clear of the block. Cut your wrapper slightly long, and fix one edge to the block with several wood screws. Then rotate the rolling pin around, and the wrapper sheet should follow. I'm not sure how much 'spring' you will get, hopefully not much. At worst, reduce the diameter of the block at repeat the procedure. This isn't as good as proper rolls, but it does work.

[ettingtonliam]

If I was getting results as good as yours, I'd be delighted. If you can't get any photos of your prototype from the top, look on Roger's thread for Speedy. I'm sure hes had some photos recently of the cladding on top of the boiler of 1501 (the full size one) and its far from perfect, just can't be seen from the ground.
If anyone criticises yours, cross your fingers behind your back, and tell them that the prototytpe was just the same, and how much effort you had to put in to replicate it.

[David]

I know the real ones were all over the shop, but it's not what we want for our little ones!

I had another look this morning and I still can't see where things have gone cockeyed. My best guess is that the boiler isn't sitting even athwartships. But I don't have the eye for this and can't be sure, and don't know how to measure it - I tried a few things like using the chimney as a reference. If I tip it a bit to the right it might help bring the safeties in line but I really need someone else to look it over. We have at least one club member with an eagle eye for imperfections and oddities so I might ask him to see if he can spot what needs adjusting.

The problem with rotating the boiler slightly, if that is the cause, is that it means my carefully filed cladding no longer fits properly on the left, being raised above the little ledges made the other day to hold it in line and I'll have to either solder a strip to the bottom or make a new one.

For now I'll stay out of the workshop and not touch it, there's a good chance I'll learn to live with it unless the valves and dome are listing due to the boiler needing to be rotated a bit.

[Jim]

I'd agree with you David to seek the opinion of the eagle eyed expert especially if it's the one I think you mean, it pays to have a second opinion at times and especially from someone you respect and trust. Just looking at the photos you've posted so far your work looks great.

Jim

[Roger]

One thought is to do something similar to what I've used on the Pannier tank setup. I clamped some angles to the frame and supported a piece of aluminium plate vertically to give a reference plane I could rest the outside of the Pannier tanks against. Maybe there's something along those lines you could do to get a reference either side of the boiler so you can measure rather than try to do it by eye.

[David]

I've spent a few days letting this problem mature in my mind and decided what I said about tilting the boiler might be an easy thing to try without doing anything permanent.

So I played around for about an hour this afternoon using various shims under the foundation ring where it sits on the rear horn guides. I think I've arrived at a place where the dome and safeties are pointing mostly upwards but has moved the safety valve bushes slightly to the right which is the requirement. So I opened up the holes in the cladding the safeties can go through it while the cladding stays lined up with the cab centerline.

The safeties can't do their secondary job of locating the cladding because the holes they go through are huge now, but the alignment is better. So that was a good result. I'll need to put some washers under them because they buckle the cladding if I tighten them.

Now the fore-aft alignment needs fixing if possible. The safeties, so the boiler itself, needs to go forwards about 3mm so they line up properly with features on the cladding. This means making the clearance in the spectacle plate bigger so the stays can get through because they're butting against it now, and also putting some relief at the top of a frame stay where the bush for an inspection plug will be. That bush is basically pushed up against the stay at the moment. This may not be worth doing.

Now I have the lateral alignment a bit better I feel it might be worth having a go at the barrel wrapper.

Unfortunately none of the above has given me more room for the reversing screw. I was hoping rotating the boiler might have given to relief there but it didn't.

[suctionhose]

David,
None of the above sounds abnormal to me! It's the nature of the beast. I've learned so much from model engineering in a practical sense. The perfect plan usually goes haywire on the first day! The skill is to pull it together at the end. It's always a bit of fudge and some compromise.

The quest for perfection always ends in disappointment because a hand made / one off can never be perfect. Getting one of these things together so the wheels go round is a far greater challenge than most people ever set themselves. Even among builders, many fall by the wayside when it comes to the final assembly (how many never get finished?)

It's time to make the best of what you've made - which is very good by anyone's standard - and be happy with the last chapter!

I'm certain the detailed commentary you provide is far more inspirational to others than pictures of "alleged' perfection (which doesn't actually exist!)

[David]

Thanks Ross. At least making the wheels go around is mostly not stuffing up the machining ops. I'm firmly convinced sheet metal forming is a difficult job that requires skill and patience I neither have nor want and is best done by someone else!

However it would be stupid to have spent 6 years on the project only to give it away now. I was determined to get it running on air a few years ago so it didn't become another 'rolling chassis under the bench'. Then the boiler had to be done last year so it didn't become a 'runs on air under the bench'. Now the cladding must be done because I'll be mightily embarrassed if I don't get it 'finished'.

I appreciate the kind words from the forum members, putting up with my constant whinging about how hard things are.

This afternoon I'll have a look at the lines I scribed onto the spectacle plate from around the cladding and see what the situation is regarding moving the boiler forwards. I won't do anything yet though, cutting more away from the spectacle plate and worse, in a frame stretcher where it is visible, is not something I should rush into.

[David]

Spent another hour or so on the firebox cladding tonight. Much grinding in various places has allowed the boiler to move forward the requisite number of mm and I think the thing is as good as it's going to get. One of the grinds was in a place that just shows outside the cladding on the spectacle plate due to an unfortunately sited boiler stay.

Now I'm wondering if the cladding can be made a mm or two less in height as there seems to be a hell of a gap under it and I'll need washers about 3mm thick for the safeties to seat on. I won't think any more about that until I've done the barrel wrapper and see how they sit relative to each other. I'm told on real locos the top of the barrel and the top of the firebox were about level so once they're both done I can see if the firebox cladding needs to come down. I can't bring it down too much or the top of the spectacle plate cut out will start showing.

Didn't want to push my luck by marking and drilling holes for the washout plug castings that arrived the other day.

The wrapper still needs to be soldered to the 'throatplate' too, but the throatplate needs an awful lot of tidying up and cleaning before I do that.

There is a ball in a safety valve now, but still waiting on the springs. They should be here tomorrow or early next week.

Plus I wanted to get onto trying to wire up the tool length sensor that arrived last week for the Tormach. That story is in my CNC thread for those interested - short story: it seems to work.

[mugbuilder]

For heavens sake David , chill out a bit.Now you know what the rest of us have been going through for decades. The average engine is always a bit rough around the edges and a lot are as rough as bags but they give their builders a lot of satisfaction.If you are looking for perfection then you should give up now and throw the lot in the bin. Your work is a lot better than the average and better than most when you considder that it is a first effort at starting from scratch. So you have to fiddle about with things to get them to sit right? What do you think that the rest of us do.The reverser will have to be moved away from the firebox side a bit but so what? You will never be happy with the engine when it is running because it will be like a full size one, always needing some maintainance or reepair. That is half the fun of model engineering.

[David]

LOL! Yeah, ok. I thought it would easy ;)

Didn't work on the mogul tonight. Started on some new parts for the father-in-law's loco on the manual mill. I'm using the Tormach tool system more and more on the manual mill. Stick in a 3/4" collet and lots of tools ready to put in, including a nice little 4 insert shell mill I've not used on the Tormach but that was ideal for cleaning up some 25mm sq steel. All with less stick-out than my normal ER-32 collet on an MT3 arbor. A spring loaded drawbar using belleville washers and a lever would make it really easy to work with. It does feel a bit weird not thinking about work-coordinate systems, tool lengths, or carefully setting Z=0 these days. The manual mill doesn't even have a DRO scale fitted to it's column or spindle.

Also mucked about with the PathPilot controller, having a look under the covers, software-wise. It has some files where you can define custom threads for the conversational programming so I tried to put in some ME threads using info from the F360 files atgordon did. It didn't work but it is a supported feature so I'll write to Tormach if I can't make it go. This will allow me to just select say 3/8x32 ME and PathPilot should fill in most of the info like maj/min dias etc. I also found the file where material properties are defined and if I looked into that I could get more than 'plastic' and 'aluminum' to show up.

Roger you'll be interest to know I found an undocumented command you can give PathPilot presumably to define axis backlash - it's called SET_AXIS_BACKLASH. There was also remote desktop access using TeamViewer. Given a PathPilot controller is just GNU/Linux box I added the openssh-server package and can now log in to a command shell remotely and I don't have to do all the exploring standing at the machine.

There is a bunch of people out there making PathPilot work with other CNC machines and other drivers by tweaking the LinuxCNC config that PathPilot sits on. I don't want to go down that route but being a software guy I'm still interested. I think Tormach have done a good job and they did it in such a way that it can be used with other machines if you're determined enough. I'm guessing it's by design to allow for the evolution of their own products such as moving to servos or making a CNC lathe with a turret.

[David]

Today say the crinolines for the boiler barrel done. This was useful because it shows how the barrel wrapper is positioned in relation to the firebox part and also how much space there is near the weighshaft lever. It all looks good. A perfectly sized offcut of the MDF I use as a sacrificial material on the Tormach came into play and the CNC machine made very short work of cutting 3 rings. Being MDF I should seal them with something or they'll swell or collapse I expect.

I also made one of the safety valve spring retainers because I already had a short length of 3/8x32 thread. The springs arrived today but I keep forgetting I need to make the plunger that sits over the ball. So that's the next job. A sharp tap on a ball (now the designated seating ball) seems to have given a good seal on the milled seat. I put another ball in there and can't blow through it.

[David]

With a running day coming up on Saturday I had to get stuck in and finish the safety valves so I can test them. I made the stainless steel plungers and spring seats yesterday, then today another one of those threaded parts with the 5 holes in it and that was all the parts done.

I made the spring seats because I only have 1/4" stainless steel rod for the plungers and the spring ID is 5mm which I thought might be a bit close.

Then I had to make a couple of 1/2-26 to 3/8-32 adapters because the red train has 1/2-26 holes in its dome. I made these out of 3/4" hex brass. I didn't have a die for the 1/2-26 thread and couldn't be bothered setting up the RapidTurn to do it so I cut it them on the manual lathe. This had the benefit of forcing me to understand the threading diagram on the lathe properly - I've only owned it 8 years! Metric pitches are pretty easy because they are all combinations of a 24, 48, and 120/127 gear. I never understood what it was telling me for imperial pitches but I have it now. I put a different sized gear on for the first time to get my 26 TPI.

The only thing I can think of that will be a problem is if the springs I bought are significantly different in strength to the ones used in Mug Builder's valves because I've used his dimensions. Hopefully the springs are close enough that they will work within the range of adjustment available.

Now I have to fix the plumbing on red train's tender. Some longer plastic hoses and some way of clamping them onto the metal plumbing so they don't get air and don't fall off. I should really take the injectors off and check them too, as at least one of them was blocked last running day.

[mugbuilder]

These safety valves are mainly cosmetic as the pop valve that will be fitted in the dome will be easily enough on it's own to release any excess pressure. They will only release steam slowly and are prone to dribbling a bit after a while. They can be tested OK on compressed air to see if the spring is suitable and there is miles of adjustment that will suit most springs. I think that it is a waste of time to adapt them to your 0-4-0 to try them out. They are not meant for that type of service and are likely to disapoint as they do not open and close like a pop valve does and can releses a lot of pressure before closing.
.

[David]

I hadn't read the above post until now, which is after the running day. In any case I wanted to see something I've made doing it's job so ran with them. They were not sufficient on their own to get rid of excess steam when standing still with the blower going and the fire roaring, but they also might have needed more tweaking. It never occurred to me to test them with compressed air! As Mug Builder said above the mogul will have a 3rd safety valve that will be doing the heavy lifting. Out on the track I never had enough pressure for it to matter - if the needle does get to the red line I use the injectors or open the fire hole door and it drops quickly enough. The safeties did leak and spit and so on but that was okay, they didn't seem to be costing me enough steam to worry notice. I'm calling them a success - they opened, they shut, mostly, and I didn't have to worry about them.

Not related to the 24 class mogul the good news re injectors is I had two that worked all afternoon. The new longer pipes from the tender to the loco, along with some wire wrapped around with the ends twisted to make a clamp where they slid onto the fixed plumbing under the tender, must have made a difference. This was particularly noticeable on the left hand side which used to only work from about 40-70 PSI. Today it would pick up at 90+ PSI. I was sure the previous lengths of tube were on tight and not leaking, but obviously I was wrong. Really pleased with that.

With working injectors I was able to keep a more stable water level, using them more often for less time, with less effect on the pressure. That makes a significant difference to how easy it is to drive, and a lot less stressful. It was nice to look at something other than the overflows.

A trouble-free run aside from the blower getting blocked at some point, but that happens and should be easy to fix.

I only use it in the station so that didn't cause much trouble. But I was told today I should use it a bit on the track because the coal we burn now needs more draft than the loco provides on it's own. We have some lengthly stretches of even or downhill grades where you're coasting with not much draft, which is apparently where the blower is good even though you're moving.

Back on the 24 class I marked out the boiler barrel cladding this morning and found someone with rollers to roll it up. So next steps are to cut it out, make the hole for the dome bush, and sand off the galvanising on the outside.

[steamer5]

Hi David,
Nice that you had a an almost trouble free run! Doesn’t it make a day playing.....err the serious work.....of trains so much more pleasurable.
As a suggestion on your flexible tube between engine & tender, I use silicon tubing, if you get it say 1 mm smaller in diameter than your solid pipes it then has to be a tight fit, which if you every have to take the tender off makes removing the tube easier than having to cut / retire your clamps. Even using like for like diameters it will be a bit more than a slip fit.

Looking forward to your next update.

Cheers Kerrin

[David]

Sounds like a good idea Kerrin, thanks. The plastic tube I'm using is quite difficult to get off the fittings on the loco because they have prominent barbs on them at present. For now I'm going to leave everything exactly as-is and see what happens next month.

The running was a lot easier and more relaxed. It's surprising how simple it is when things work like they should.