Overhaul of a 9F

[don9f]

No, they are extremely powerful and will obviously take a very heavy load. I recall at the Urmston track one day hauling 26 adults with ease (still got the vhs video somewhere), but unfortunately they couldn’t spare any more passenger cars to try even more. That was an aluminium track and you just know that with steel track, they would take many more! You’ve got to be sure that your drawgear is up to such loads.....don’t want a runaway!

Witnessed a 5 inch Class 47 runaway from its train at a nearby track just before Christmas. It must have had a controller without a “Deadmans” feature as it powered off on its own, dragging the controller behind it, bizarrely catching its horn switch as it went, sounding its own distress signal ! Fortunately someone managed to stop it before it got too fast.

Cheers Don

[Cro]

Well hopefully one day I'll see mine doing that!

Yeah run away trains are not nice. I was at a private GL5 track last year when a 5" N2 broke away from driving truck with full regulator. It should have come down the main line past the signal box I was in running out to kick it off the track (or broken my ankle) but the first point was stuck pointing into the yard where a 5" K1 was sat on turntable in full steam waiting to come off shed. The K1 ended up nose first in the fit 6' off the turntable and N2 on its side in the gravel spinning its wheels!

Not a pretty sight.

Adam

[terrier060]

Yes frightening Adam - I am going to fit a bicycle brake cable or something similar to the rear buffer beam, just in case the worse should happen.
Ed

[simplyloco]

Jan 27, 2018 21:47:46 GMT don9f said:

Do tell!

Don

Don
The LBSC method suggested bending the connecting pipes in the smokebox to make them fit, which is a bit tricky, so I'll just pinch your setup . 
Many thanks
I might even improve my cylinder connections by fitting Rt. Angle connectors so that the superheater slides in and on easily so to speak!
Regards
John

[dhamblin]

Grandad had a runaway with his Britannia and told me he had difficulty catching the loco and closing the regulator. It was just like the 9F in that you pull the handle towards you to open, so in a runaway you have to push it. The modification was to change it to a horizontal arrangement where pulling the handle towards you now closed it (it is the dome mounted rather than smokebox type so it just required a change to the backhead pivot point).

With the vertical handle type I wonder whether a discrete cable could be fitted with a ring on the other end such that if you can get a finger on it the cable could pull the handle back towards the backhead.

Regards,

Dan

[Jim]

While I'm not expecting a coupling failure 70036 is fitted with a removable safety cable inside a black tube to resemble a vac hose pipe connecting it to the CCT driving truck.

The photo shows the SS 7X19 construction, 2.4.mm flexible rigging wire, with a breaking strain of 395 kg in place. It can be easily removed when not needed. I swaged a soft eye on both ends


An anchor point has also been provided on the rear of the truck for a safety chain connection to a passenger carriage if needed.

Jim

[GWR 101]

Jim, I like that, it must be terrible to see ones pride and joy heading off into the distance. Better safe than sorry. Regards Paul

[don9f]

Hi Dan, Jim & Paul, good ideas etc. and for my part, I have also got a secondary coupling arrangement....using a small stainless “D” shackle fitted to a bracket underneath the tender buffer beam that will line up with the safety chains on our society’s riding cars. The tender drawhook is homemade from EN24T, as per Bob’s (92220) posts on his thread and a special adapter made from gauge plate fits over the hook for the primary coupling to the riding cars. This was supplied by another society member who had access to spark erosion equipment, but in my photo, it isn’t quite finished yet.

As well as the actual drawhook, of course it’s attachment to the buffer beam, the buffer beam’s attachment to the frames, the front drag box likewise and the drawbar to the engine and its drag box etc. all have to be capable of taking the load. When I built my tender, the reinforcing “channel” that forms part of the rear buffer beam assembly was an aluminium casting. In order to strengthen this assembly for “heavy hauling”, I added a vee shaped bent steel strip that picked up where the drawhook passed through, then went forwards and outwards to become attached to the frames with the next tank support towards the front (hope that makes sense, haven’t got a photo). My concern was that without it and only aluminium for the channel, the buffer beam might bend under heavy load.

Cheers   Don

[Jim]

That is a very nice coupling I must say Don. Mine is to the same design but fabricated and not nearly as nice looking.

Jim.

[don9f]

Hi, the smokebox pipework is now complete....most of it is new and the really fiddly bits to re-make were the external steam pipes to the steamchests. They are 7/16 x 18g pipes and have a fairly sharp bend immediately where they exit the threaded fittings in the smokebox wall and a slight longitudinal offset to line up correctly with the flanges on top of the steamchests, which are of course angled downwards to the rear. Everything has to line up to be able to connect up the pipes from the superheater easily. They also carry a check valve in the oil line from the lubricator (one for each cylinder). I have retained the original sealing arrangement of nuts and lead washers, as this works reasonably well due to the relatively large smokebox diameter.

The snifting valve has been cleaned and “re-balled” and new pipe connects it to the wet header. This pipe, the valve itself and fittings are bigger than the drawing shows, as experience early on showed that there was considerable retarding effect when running with the regulator closed due to the vacuum that can be created. There was some good discussion about this problem that can affect piston valve engines in another thread and what you really don’t want is smokebox gas/char being sucked down the blastpipe.

Not shown in the photo is the pipe connecting a hollow stay to the blower jets. This is another original feature I have retained, as my fellow club member with another 9F, has opted to follow the full size arrangement of an external pipe feeding his and unfortunately regrets this a bit, as he suffers a bit of a water problem when turning it on!

The new main steam pipe behind the wet header, to the regulator is also fitted, along with sealing washers, as this assembly dictates the exact longitudinal position of the connections to the external pipes, all of which had to be taken into account when making the superheater assembly jig.

Next job is to clean up and check the regulator valve and it’s operating shaft/linkage, then think about replacing the “arch” in the firebox. The original was made from copper but that didn’t last long! It then ran for a few years without one, but I have acquired some 3mm Nimonic steel sheet and might have a go at one from that....it is secured in place by bolts through some hollow stays in the throatplate area.

Cheers   Don

[Oily Rag]

The snifter arrangement you have has solved a problem I have with the design of my QR C17 #253 loco I have drawn. Simple but I needed your pic to enlighten me.
Thank you.

[don9f]

Hi Dazza, you’re welcome! Obviously when the smokebox is in place, the snifter is easily accessible for cleaning if required, just inside the door.

Cheers Don

[don9f]

Hi, the Les Warnett 9F drawings that I have don’t actually show a regulator valve, only the housing for it in the boiler, plus the gland for the operating shaft to pass through. I no longer have any magazine construction articles and can’t remember whether it was ever described or not....I just remember designing my own.

Real 9Fs have a simple slide valve regulator, mounted horizontally in the dome and operated by a series of cranks, links & levers. As you may know, when first built there were problems that could result in the regulator being difficult to close, under certain conditions!
The remedy was to reduce the cross sectional area of the valve (by around 50% IIRC), which apparently hardly affected the performance of the loco, but resulted in much reduced back pressure on the valve under whatever conditions that were causing the problem (probably to do with amount of regulator opening / steamchest pressure / boiler pressure etc.).

Anyway, I must have decided when building mine that a horizontal valve was too complicated and opted for a vertical valve instead. This has two ports, where the first port becomes fully open before the second port opens. This gives somewhat progressive opening and is similar but simpler than the real thing, where the valve actually opens in two separate stages....hence the terms ”1st & 2nd valves”.

I didn’t take any photos before I dismantled it, but it really only needed a bit of cleaning up, lapping the valve in and replacing the ‘o’ ring that forms the seal onto the main steam pipe that passes to the wet header. The photos show the design of the valve and some of the detail of how it is operated by rodding external to the boiler....2nd, 3rd & 4th show shut, partly open and nearly fullly open.

The main body with the port face is gunmetal, the valve is brass and all the parts that make up the operating mechanism are stainless. I took a video of it installed and working in-situ, but it seems you cannot upload videos to Imgur....hadn’t tried that until today! When fully assembled, the operating shaft passes through an ‘o’ ring in the dummy stuffing gland on the side of the boiler. Photos of real engines, often show limescale and staining from these stuffing glands leaking!

Cheers   Don

[don9f]

Hi, a little while ago I had thought that maybe my work on overhauling the frames etc. of the 9F was nearly finished….WRONG!


Up until recently, I had not really disturbed the motion of the engine, considering that it would probably be ok, for further service. But after reading up on valve setting etc. and deciding to check mine over, I realised that realistically, I really ought to do some more work first on reducing the little bits of wear and play that had become apparent in various places. There were a number of areas that would benefit from this….particularly “lost motion” concerning the expansion links, die blocks and reversing gear, but also to some of the bushes and gradient pins of the coupling rods.


To be able to remove the front gradient pins each side on this engine, the rods have to be completely removed, as there isn’t really enough working room to be able to get them out between the spokes of the wheels (the rear ones can be done like this). Obviously this entails removing the Return cranks and their eccentric rods, then the Con rods etc. In the end I was pleased I had done this, as I found that one of the Return Crank ball bearings was a bit rough and I had not been aware of this before!
New bearings were therefore obtained and fitted.

During the process of overhauling the expansion link bearings and making new die blocks, I remembered something that may be of interest to any future builders of a Les Warnett 9F and possibly others with similar valve gear….

When I was building the engine, I found that if fully assembled as per the drawings, the completed expansion links could not be assembled into their trunnion bearing brackets....they just wouldn't go in. The expansion link trunnion shafts have some small hardened steel bushes loctited into place on them and these (at least on my 9F) had to be removed to be able to fit the expansion links into their brackets and even then, only after having first filed a small recess into the outer bearing holders (recess subsequently not visible). The bushes were then loctited in place afterwards and the actual gunmetal bearings could then be fitted….each held in place on mine by 4 x 10ba hex screws. into tapped holes in the brackets.

This photo shows that even with the inner hardened bush removed, the link still won't come out!


During dismantling, I managed to shear off two of these 10ba screws on one of the inner trunnion bearings Arrrrgh! I suspect it was probably due to paint on the threads and I wish I’d been a bit more careful when they started going tight! Anyway, I made a drilling bush, exactly mimicking the spacing of the four tapped holes, secured it in place by the two good holes and when starting to drill out the broken remains of the other two, they both “spun out”, leaving the gunmetal threads undamaged….that was a stroke of luck!


This is actually a photo looking down onto the RH side inner trunnion brearing/bracket, but shows the awkward position of two hex 10ba screws that had sheared off on the LH side


This photo shows the area I had filed during construction, to be able to fit the links


Here the RH link is removed along with its original hardened bushes, die block, trunnion bearings and at the top, the drill bush used to drill out the offending broken screws on the other side. The bearings are secured by screws through the clearance holes in them....the tapped holes are for removal using jacking screws....just like the real thing.


New die blocks were made on the rotary table from gauge plate (originals were hand filed), the nominal working radius of 6 7/8 inches entailed some serious overhanging the edge of my table, but it all worked out ok. The new die blocks were individually hand finished to fit to each expansion link, then hardened. The trunnion bearings and aforementioned hardened bushes were overhauled and these two operations really made a significant difference to the “lost motion” problem.


Here we are all cleaned up and ready to refit....note the eccentric bush in the tail of the expansion link! Must have been to correct a minor error of eccentric rod length, during original valve setting


The final bit of attention in this area was to eliminate the fore & aft free play that had developed in the reverser screw arrangement….mostly in the thrust bearing, but also a bit in the trunnion nut and its die blocks.
I was very fortunate back in the 1980's that a fellow 9F modeller in the Urmston Society kindly made the reverser screw and nut for me with a 12 tpi LH square thread....much better than the 5/16 Whit that I came up with....I think the full size uses a 4 start thread!



I’m now very pleased I did all this extra work….obviously didn’t really look hard enough first time round!


Cheers for now   Don

[don9f]

Hi, I’m aware that it’s been over 2 months since I last updated this thread and although I’ve been busy with all sorts of engineering things, unfortunately I’ve not managed to do much to the 9F. Since the last update I’ve assembled and wired up a 5 inch gauge battery powered model of a BR Class 25 diesel loco (as yet unpainted). I decided to order one earlier in the year, to give me something to run on our club track this season, which of course has already begun! Tomorrow should be it’s first day in passenger service.
Anyway there are some 9F matters to report....firstly and thanks to Adam, I now have a pair of excellent scale injector steam valves, which will replace the ones I made back in the early days. These were a bit overscale, plus did not have the mounting bosses to enable them to fit to a mounting plate, like the real thing. As with various other fittings on the 9F, these valves are outside the cab and are very prominent on the fireman’s side. I have made said mounting plate and fortunately when building this loco, although the valves were slightly overscale, the spindle centres were correctly positioned, so the new valves/plate will line up ok with the existing holes in the cab front.





About a month ago, the boiler was formally hydraulically tested and issued with the relevant paperwork. This happened almost 22 years since it’s last test and of course gives me the go ahead to carry on and reassemble the boiler to the frames and pipe up etc. ready for a steam test. Just yesterday I completed refitting all the crinolines in readiness for new lagging, then the job of refitting the cladding....hoping I can pick up all the original 12ba tapped holes in the crinolines!





I would really like to crack on with this but there’s house DIY to do, gardening, club running, my one day a week dabbling in full size steam, family visits....etc. etc. but I’ll try!

Cheers Don

[Deleted]

Looking great Don...I love the crinolines, I'd like to do something similar to 4472 when I get there...I have only ever seen A4's with this framework but would assume that the other LNER pacific's would have something similar? I feel some more research is needed...
Adam's fittings are works of art aren't they? Don't worry about the 2 month break, I've just had nearly 4 myself....I'me looking forward to the next update sir...

Pete

[don9f]

Hi Pete, I can’t speak from experience of LNER engines but I’m sure it will be something similar. Once it’s all made, the crinoline framework pretty much all locks together and holds its position, but getting to that point is a right fiddle! Mine is a simplified version of the real thing, which is not fastened at all to the barrel section and has just a few strategically placed screws holding the lower edges of the firebox section around the foundation ring.

The BR Standards have bosses welded on here & there around the firebox and these obviously provide a positive location for bits of crinoline....the barrel bits just assemble into a giant “cage” and have numerous “stand offs” that hold it all the right distance from the actual barrel plates....if that makes sense. Hopefully someone can enlighten us to how this was all done on earlier designs which might not have had anything welded to the firebox plates?

Cheers Don

[don9f]

Now that my Class 25 loco has at least got its first coats of paint on, the pressure is off and it can run like that for a bit so I’ve had some time on the 9F in the last couple of weeks and achieved a bit more progress:-

I lagged the barrel in 3mm ceramic fibre blanket, cutting pieces to fit between the centrelines of adjacent crinolines and tucking the edges under to help keep everything in place. Obviously a number of holes have to be cut out here & there to accommodate boiler bushes and the various mounting pads etc. that are attached to the outside of the barrel. Les Warnett intended that some of these were to take brackets for supporting the running boards, but I never actually used them for that purpose. There is also a large pad under the front end of the barrel that sits in the support cradle that is on top of one of the frame stretchers. Bits of masking tape held any lagging in place that wouldn’t otherwise stay put, until I could refit the barrel cladding....which is in one single piece. In my haste I forgot to take any photos at that stage.

Before I could permanently fit the firebox cladding, I needed to accurately locate the positions of the holes for attaching the new injector steam valve mounting plate. The sides and top are again one single piece, so this was fitted with just a few screws to positively locate it and the cab floor and the cab itself also temporarily fitted so I could line up the injector steam valves/spindles with the pre-existing holes in the cab front. The real engines have universal joints as part of this arrangement to accommodate any misalignment but mine hasn’t, so it was important to get this right.



I used a photo of Evening Star to help with the location.



Referring again to the real thing, these mounting plates are secured by studs/nuts to threaded bosses, welded onto the firebox outer wrapper, the cladding sheets just having holes in the right places for the bosses to protrude through. On my model, the mounting plate is simply secured to the cladding sheet via small spacers (same for the ejector duplex valve on the driver’s side).

My chosen method for such jobs is to hold the plate in the right place, mark through the mounting holes, then drill 12ba tapping size with a small 12v drill....something that I acquired in my model aircraft days and is extremely useful. Once tapped, the plate can be mounted and all checked for correct positioning.





Once happy, the firebox cladding was removed and 12ba brass nuts soft soldered to the inside surface....subsequently giving the plate mounting screws a good fix.



Hopefully the next job will be to lag the firebox in a similar manner to the barrel using 3mm or thinner blanket....some areas near the top of the firebox don’t have much of a gap for lagging. With this job completed, the boiler can be repainted, as it looks a bit scruffy, then remounted on the frames.

Cheers   Don

[don9f]

Well I wasn’t invited to the Royal Wedding, so I spent a whole day on the 9F instead! The firebox is lagged....a fiddly job due to all the stays sticking out, plus other cutouts in the blanket being needed to clear things like the dummy mid feather doors that are attached to the cladding sheet. At the top of the firebox, there is only 2 - 3mm “gap” under the cladding.

This photo shows the inside of my “one piece” cladding sheet, visible are some soft soldered nuts for one of the firebox steps, other soldered nuts for the duplex valve mounting plate and so on, nuts securing handrail stanchions, dummy washout plugs/recesses and dummy mid feather doors.


Again, pieces of lagging were cut to fit between adjacent bits of crinoline and it was all tucked under at the edges, resulting eventually in quite a neat job I thought. I was wearing gloves because of the fibres and the holes for the stays to protrude through were made simply by pressing my thumb hard on the ends of them.



The cladding sheet was then refitted and fully secured, along with the belpaire corner pieces and the banding. There really wasn’t any room for lagging at the backhead, so the two parts of its cladding were just fitted without.....


The job took all day and in total, this firebox cladding is secured by well over 100 12ba hex screws....all of which have to be quite short so as to not touch the actual copper parts. Fortunately, most of them were reused from the original build but of course I had lost a few, dropped a few etc. etc. and had to cut some new ones from my stock of more modern, slightly larger head, 1/4 inch long ones....as mentioned before, you can’t get “proper” 12ba hexagon these days! They’re all overscale anyway as the full size uses 3/8th whitworth and in 5 inch gauge they would be really small!

Next will have to be a thorough clean up and a repaint....I don’t like painting!

Cheers   Don

[don9f]

Hi, as hinted at before, I’m not very keen on the painting....as long as the model looks “something like”, then I’m happy. In the case of a 9F, you could paint the entire thing in a sort of filthy colour and it would be completely typical of the real things in BR days! However, I made a bit more of an effort than that and when first painting the completed boiler back in the late 1980’s, used “CarPlan” grey primer and Satin Black paint. I followed some advice I had read somewhere and thoroughly cleaned the brass cladding several times with Electrical Cleaner (Isopropynol). The area being painted was then warmed with a hot air gun and the primer sprayed on, followed by 3 coats of the Satin Black.

I’m not for one minute suggesting that this is the right way to paint a model loco, but it worked for me back then and having just refitted all the cladding in the last few days, I was aware just how remarkably well this process had stood the test of time. Once I had re-cleaned the whole boiler several times with the same Electrical Cleaner, I was almost tempted to just touch up areas that had got knocked or scratched etc. But in the end I touch primed those areas, then gave the whole thing a couple of fresh coats of Halfords Satin Black, having read that it was supposed to be reasonable quality acrylic. I don’t mind one bit that the finish is not brilliant and I honestly wouldn’t want a 9F that had gleaming paintwork....that’s just my personal preference.

I had to carry out a few jobs before I could mount the boiler on the frames, as access later would be either very difficult or impossible:-

   Connect a short length of steam pipe to the leading brake cylinder for later connection under the LH running board.
   Connect a further short length to the cylinder cocks tee/drip valve, reason as above.
   Fit the blowdown valve to the boiler throatplate.
   Fit the ash pan.
   Fit the front and rear damper operating rods to the damper door cranks.
   Fit a new o ring to the cylinder exhaust/smokebox connection.

The boiler was then reunited with the frames and secured in place....smokebox bolted to its saddle and the expansion supports/clamps assembled at the rear. I then wheeled it outside for a photo in the evening sunshine!



The small holes visible in the back head cladding are for things like the whistle operating shaft brackets, the bracket for the eagerly awaited Mk6 Graduable Steam Brake Valve and the brake cylinder oilers. The big cutouts are obviously where the firehole door runners fit and a bit of masking tape covers what will remain bare copper, where the boiler ID No is stamped....still a bit more painting to do yet.


In this next photo, the damper operating linkage and the rear boiler expansion supports/clamps can be more clearly seen, as can all the gunge and dirt that I should have cleaned off the cab floor supports, rear drag beam etc. before photographing it! I will make that the next job, before fitting the cab floor....



I still have a few more bits & pieces to add yet and before the cab goes on, will give the upper parts of the boiler a final coat of paint....then it’s on to assembling the regulator valve and it’s operating linkage, the superheaters and the other pipework in the smokebox.

Cheers for now   Don