NSW 'B' class mogul

[David]

Thanks Barry. I already have the sledge hammer so may as well use it! I can spring the legs over the nut so that's ok. I have just realised the bigger problem will show up if I have to take it apart and don't want to scratch the firebox paint.

I squared up the internal corners today and drilled the holes for the bolts.

I used the sledge hammer again this afternoon to make the reach rod.



If I'd had something like 50 or 60 x 3mm I would have used that with lots of clamps down each side. I only had 30 x 3mm and it looked a bit flimsy and difficult to hold. Looking through the stockpile out the back I found some 40 x 40 x 3mm angle so decided to use that. Put one part of the angle in the vise and hope it adds some rigidity to the piece being cut.

It sort of worked. Angles are not often 90deg and this one wasn't. I figured the difference in height on the Y axis wouldn't matter much. I left 0.5mm axially like one big tab and it worked well enough except it broke right through on the right end so I had to skip doing a finishing pass. I'd only allowed 0.1mm for the finish pass, so draw filing and cleaning up with sandpaper probably got me to size anyway!

There were two improvised screw jacks under the MDF in the photo below near the toolmakers clamps and they may have contributed to the X axis deviation.

The break-through on the right may have worked out in my favour. It meant a lot less manual cleaning up of the rounded end, whereas the rest of it took a little more work but was all straight lines.

I used the 6mm roughing endmill, 1400rpm, about 70mm/min. Full width-of-cut, and the doc was about 0.8mm with a ramp entry. So it took 3 goes around to get to the picture below.

[Roger]

Hi David,
That's a fairly typical result when machining sheet, and perfectly acceptable. These days I tend to go to the full depth but use long sloping nibs to hold the parts instead. It still breaks through in places and not in others, but it's the nibs that are doing the holding so that doesn't matter. I use nibs that are no less than 10mm overall length and say 0.5mm high. That generally guarantees that they are always effective but not so massive as to obscure the top of the profile and need too much cleaning up.

That came out really well, you should be pleased with it. I still think you're a little high with the feed though, I would have used no more than 50mm/min.

[David]

Well, I was thinking of how disapproving you would be when I backed it off to 70mm/min from 90mm/min ;)

I'll see how long the rougher lasts. It's done 3 jobs now and still seems ok.

[Roger]

Jul 15, 2019 12:18:09 GMT David said:

Well, I was thinking of how disapproving you would be when I backed it off to 70mm/min from 90mm/min

I'll see how long the rougher lasts. It's done 3 jobs now and still seems ok.

Hi David,
My approval is of no consequence, what works is all that matters. If that works as well or better than what I do then that's something I'll have to revisit. I will confess to erring on the side of caution, but that's because I want to be able to walk away and be pretty sure it won't end in tears. If you're standing over it or nearby, you can be a bit braver.

[David]

No pictures but I've just spent about 6 hours mucking about with the mogul after work.

I worked on getting the reversing screw into place and had to move it out a few mm, with the cab cutout also being taken out a few mm to allow the nut to pass through it. I had the flint in my hand to light to torch and dismantle the bracket the screw sits on so I could move the top plate with the mounting holes over when at the last second I had the idea of putting slots in it rather than the clearance holes. This both avoided a great deal of work as it had already been milled square etc, and there was no guarantee I'd get the holes in the right place the second time either. The slots gave me enough leeway to play around with the position before deciding how much to take out of the cab front. A 2mm endmill on the manual mill did well.

The problem came about because I made the cab cutout, screw mounting bracket, etc to the design without taking into account the fact my boiler is too wide. Pretty much everything on the loco and tender were made to the drawings and it all fits and it started working first time on air so I'm in the habit of (usually) checking to ensure I can figure out all the dimensions and then making what the drawing says. The firebox area has been an aggravating exception to this. They're very good plans.

The reach rod fork fouls the front of the reversing screw front bracket when it's back past about half way so I'll have to think about the neatest way to fix that.

Then the instructions say to get it running on air to find the limits of where the weighshaft lever should be allowed to go. That took some doing after two years and many dismantlements! A few hours later and having had to take the brake rods off to get the nuts on the back of the driven wheel crankpins, replace some split pins, put the inlet manifold on properly, etc, etc, it came to life and immediately got stuck in forward gear when the screw through one of the die blocks worked its way out. This happened to my father-in-law's loco a few months back and broke one of the hangers that support the expansion link. Luckily that didn't happen here.

The reach rod didn't get sorted tonight, but now it's running and the reversing screw is mounted I've got everything ready.

[David]

I did the fitting for the reach rod tonight. Luckily it was long and I removed about 3mm. I think it's good to solder into the fork now.



I made the little fitted bolt that attaches it to the weighshaft lever, took about 40 mins trying to get the dias as close as possible to reduce lost movement. I parted it off, picked it up, dropped it because it burnt my fingers, and never saw it again. After about 5 minutes of searching I made another one, luckily more quickly. The threaded section is a bit short but some loctite on the threads should sort it.

You can see the kink required to get it lined up. I would have preferred less of this, but nothing to be done about it.



It's small progress but it feels like a bit of a milestone given I started on the reversing screw bracket back in February and I've been worrying all that time about how it will fit around the boiler and in the cab etc.

Running on air again I can see I haven't sealed up the cylinder covers with anything so plenty of air was coming out of there. I'm sure the steam chest covers don't have sealant either, and I can't remember if the piston rods and exhaust ports have their o-rings! So a bit of work to do there. At least I can check the valve timing again. The cylinder drains don't close properly either but the clevis is on a thread so I might be able to fix that without making new levers to each drain. I don't want to do all that now though, there's no need to be running it.

I'd like to make another nut for the reversing screw as the current one won't sit flat but I can't find the tap! That's pretty annoying. It's not in my ME tap/die draw where it should be, nor in my metric tap draw. No idea, but you can see the state of my workshop so it's no surprise I constantly lose things. I'd love to be as neat as Lance and Patrick at Active Atom. I'd also like to redo the location of the bracket that supports the front of the screw because it's sitting about 1mm above the base so it looks silly and lowering it will improve clearance for the legs of the reach rod fork. But realistically, that won't happen either.

Still, very pleased to have the reverser essentially done other than soldering the reach rod together.

[David]

I soldered the read rod into the fork and cleaned it up.

Than I had to check the boiler cladding with the reversing screw to ensure there was still enough room and there is the approx 1mm I was trying for and I don't want to move it out any further. But I'd forgotten about the huge 5BA hex headed screw at the widest part of the fork. Not forgotten it entirely, I knew it was a problem, but I was just indulging in some wishful thinking. I might file the head down, but even so it will make taking the fork off quite difficult if not impossible. I may just fill that hole and leave the bolt off. If the real one had two bolts I'll have to at least have the stud and nut on the outside.



While doing all that I thought of at least two ways I could have made this better but too late now.

I was going to start soldering the regulator together and to do this I had to get the wet header bush off the smokebox tubeplate which has been on there for about 18 months since we gave it a hydro test. I couldn't remember how I'd plugged it and trying to pull the plug and bush out didn't work, nor did tapping it out with a brass drift through the backhead regulator bush. I eventually pushed the steel plug into the boiler and got it out through the dome bush then when I still couldn't tap the bush out from behind I decided to apply some heat and that finally allowed me to tap it out. There's a lot of PTFE tape everywhere I need to get rid of too. I can only think to get it off the threads and flush the boiler well.

the bush and the rest of the regulator parts were all pretty dirty as they were made two years ago. They're in the phosphoric acid overnight and I'll look at the soldering again tomorrow.

[mugbuilder]

Looking good Dave.Just put a dummy bolt head on the outside. A word of advice for the future. DONT ever use thread tape anywhere as it will end up somewhere that you dont want it to.Use flexible loctite thread sealant on boiler fitttings except for the water gauge where I use loctite nut lock as this will hold your water gauge top and bottom fittings secure yet be able to removed if required down the track.

[David]

Thanks Barry.

After having to pick the thread tape out of the red loco's boiler bushes and now this one... no way will I use it again on a loco.

Today saw the front half of the regulator soldered together. I realised I'd made some sort of mistake after I'd soldered the smokebox bush on - I hadn't thought about the bolt holes in the flange! Luckily they're so far out of line I can spot new ones through from the superheater part. I couldn't have kept them lined up even if I had thought about it so no real loss. Probably shouldn't have drilled them yet.



Also made the parts the superheater elements will go into, but not soldered anything yet. I think I can solder the various parts on the wet side to get it sitting in the correct location before I solder the elements in.

Here's the setup for drilling the hole near the end. The drill sticking out the side was for me to hold the tube down because there was no room for the stirrup clamp.

After I'd done the first two holes I realised I could use my 8mm carbide spotting drill to get the holes most of the way to 3/8" so that saved some time for the later ones.



The other holes allowed a clamp both sides so they were easy.



A couple of plugs and a threaded fitting for a pipe from the snifter valve.



Given enough copper, brazing rods, and time I could probably get a couple of usable ones. Buying them seems a lot easier so I'm going to do that. They will be stainless so I'll be revisiting the silver soldering stainless thread when I get to that bit.

The tubes in my boiler have a pronounced curve to them about 2/3 of the way along so it will be interesting to see if that causes trouble. I think the tubes were soldered into the firebox at a much steeper angle than was required due to something moving during that step.

[David]

While looking at the regulator drawings this morning I noticed another mistake I'd made while soldering the front end together.

The steam pipe is meant to project through the bush and into the superheater wet header.This gives the o-ring something to sit on and I guess takes the steam past the join making it less likely to try and get around the o-ring and out between the bushes. I'd even thought this might be a good idea without having noticed it on the drawing, but decided not to for no better reason than I could stand the assembly up while soldering it if I had the pipe flush and for some reason thought the 0.5mm projection of the pipe would be okay for sealing purposes.

It might work the way I did it, but I'd always wonder whether it was as steam-tight as it should be.

So it all came apart this morning and back into the pickle to get cleaned up for another try tomorrow and the next day.

Now I have to find a way to clean up the bores the 1/2" pipe goes into - I can use a reamer on the front bush but not sure about the one in the regulator body. I may also be distorting the seat the spindle seals against so it will always have a leak.

I can't say I'm surprised. I was due for some easily avoided stuff-ups after having the reachrod seeming to go smoothly.

[David]

I soldered a new piece of tube into the regulator body, and had to make a new front flange as the original was slagged when I took it off. I didn't think I was using that much heat!

The smallest piece of brass I had to make the new bush was this lump of 62mm dia! The remains of it are somewhat smaller.



Even if the regulator body is still ok after 2 solderings and an unsoldering I can see the next tricky bit being getting the holes in the superheater header, regulator bush, and smokebox bush all lined up. I may have to make oversized holes or slots in the regulator bush. I have to decide what to do before soldering the new one on though.

I think the way to go would have been only drill tapping sized holes in the superheater, then spot them through the regulator bush and into the boiler bush when the front of the regulator was finished. Too late now.

It's amazing how many ways you can get this stuff wrong even when you try to think it through. I have to say it's a lot easier to fix code than fix locos.

[Roger]

I'm not sure you should be using Brass for that, shouldn't it be Phosphor Bronze? I think this will suffer from Dezincification and crumble in time.

[David]

I'm sure it would be better, but it shouldn't see much 'water' as opposed to steam so I'm hoping brass will be okay in this case. The boiler bush is bronze so will be okay and if this stuff crumbles in X years I can rebuild it and know for sure not to do it again.

[Roger]

Jul 22, 2019 10:43:08 GMT David said:

I'm sure it would be better, but it shouldn't see much 'water' as opposed to steam so I'm hoping brass will be okay in this case. The boiler bush is bronze so will be okay and if this stuff crumbles in X years I can rebuild it and know for sure not to do it again.

Fair enough, I don't want to rain on anyone's parade, but it's worth flagging up these concerns. As long as it doesn't result in the regulator getting stuck open then it's not a big worry. I only use Phosphor Bronze inside the boiler, it's much more robust, threads won't strip as easily and it's never going to crumble.

[David]

This is outside, but it is silver soldered to the outlet pipe from the regulator valve so will be a nuisance to replace if necessary. All the inside bits inside the boiler are bronze, copper, and stainless.

Given the pipe is a slip fit into the web header with an o-ring around it, I'm wondering what would happen if it wasn't soldered into this bush, and the bush simply held it in place radially. I know you guys can't visualise it, there's a lot of bits here.

[David]

I soldered the new bush onto the regulator this afternoon. I decided to spot the holes through beforehand because there didn't seem to be any way to line all the bits up afterwards. I made the holes in the bush oversize in the hope that will help any small change during soldering.

Of course my clamp slipped during soldering but I think the solder had already taken by then. The alignment mark had been burned off the copper tube so I won't know until I've cleaned it up tomorrow.

I bought some retaining compound for the red loco tyre. The blurb says "High strength, high performance retaining compound for slip fitted parts. Ideal for gap filling up to 0.15”. Best resistance to dynamic, axial and radial loads. Recommended for retaining shafts, gears pulleys and similar cylindrical parts." so the only problem I can see is if the gap isn't big enough and it all gets squeezed out! I asked if Loctite primer would improve the strength but the guy said it would only speed up the setting time.

[racinjason]

David,
I take a cut across the surface to be bonded with a high feed rate this will leave a thread like finish without reducing the diameter. This will keep the parts concentric and give the loctite something to hold onto. I also use the loctite primer after cleaning with grease and wax remover.
Cheers Jason.

[stevep]

Jul 23, 2019 7:32:26 GMT David said:

I bought some retaining compound for the red loco tyre. The blurb says "High strength, high performance retaining compound for slip fitted parts. Ideal for gap filling up to 0.15”. Best resistance to dynamic, axial and radial loads.

0.15" - really? Suspect that should be .015"

[nonort]

I think its probably 0.15mm approximately 0.006"

[simplyloco]

Jul 23, 2019 7:49:48 GMT racinjason said:

David,
I take a cut across the surface to be bonded with a high feed rate this will leave a thread like finish without reducing the diameter. This will keep the parts concentric and give the loctite something to hold onto. I also use the loctite primer after cleaning with grease and wax remover.
Cheers Jason.

Hi Jason. I have a bottle of 'Activator' which is at least 30 years old! I don't use it anymore, I just slap the Loctite onto a smooth clean surface (50-80 RMS) and wait five minutes!
John

From the Loctite User Guide which can be found here: www.ellsworth.com/globalassets/literature-library/manufacturer/henkel-loctite/henkel-loctite-user-guide-do-it-right-loctite-maintenance-products.pdf

Primers
1. Primers activate inactive surfaces which are not required

with primerless products.

2. Primers speed cure times for faster return to service.

3. Primers speed curing through larger gaps and deep threads.

4. Primers substantially speed cure times on cold parts.

5. Primers act as cleaning agents.


Active surfaces (primer is optional): Brass, copper, bronze, iron, soft steel.


Inactive surfaces (primer is required): Pure aluminum, stainless steel,

magnesium, zinc, black oxide, cadmium, titanium, nickel, and others.

Shaft Mounted Assemblies
1. Machine shaft to 0.002" radial slip fit with 50 to 80 rms finish (second cut).

2. Clean all parts with LOCTITE® ODC-Free Cleaner & Degreaser.

3. Spray all parts (I.D. and O.D.) with LOCTITE® 7649™ Primer.

Do NOT use primer for heavy duty applications.

4. Apply a LOCTITE® 660™ Retaining Compound coating around shaft and

engagement area.

5. Assemble parts with rotating motion.

6. Wipe off excess.

7. Allow 2 hours prior to service.