Overhaul of a 9F

[don9f]

Hi, my name is Don and I’ve recently joined this forum, having awakened a long slumbering interest in Model Engineering…..


I built a Les Warnett 5 inch gauge 9F back in the 1980’s and ran it most successfully for several years at various society tracks, living in NE Lincolnshire at the time. Unfortunately sometime in 1996, during a boiler inspection\hydraulic test, we discovered a bit of a leak from one of the superheater flue silver soldered joints in the smokebox…..the test didn’t continue and its certificate wasn’t renewed at that time.

I started a stripdown, intending to carry out repairs, taking the opportunity to additionally carry out some work on the pistons & valves, but not long after, a job change and house move meant that the loco became “ Stored out of use”. Involvement in full size loco restoration (92214) became all consuming and now, over 20 years and another house move later, the model still hasn’t been repaired!

Hopefully I’ve now got the time and incentive to pick up where I left off and finally get the project under way again….mentioning a brief outline of the above on a thread within this forum. It was suggested by "92220" that maybe I could create a thread of my own, describing the progress of this “overhaul”, as it has now become, due to the long period out of use, and other work being necessary, due to minor damage etc. that has occurred during the house moves and storage in various garages etc.


I’m quite happy to have a go at this, as long as people are interested. The loco was built at a time when not much in the way of scale detail parts were available, but I was friends with Doug Hewson and for example, the reversing gearbox in the cab is the first prototype, machined and assembled from a set of castings\gears he had available at the time. Most other fittings are home made and much other detail was obtained from 92220 at York, plus 92214, initially whilst it was at Buxton, but later on when it moved to the Midland Railway Butterley, the location at which it successfully re-steamed again in 2003.


I hope during this overhaul, to enhance and update some of the features of the model, taking advantage of some of the parts and castings available today. Les Warnett had designed the model as a double chimney variant and I wanted to pair it with a BR1C type tender, not the BR1G as per Les's design. I spent my childhood near Birkenhead and it is well known that at one time in the 1960’s, the 8H Mollington Street depot there was home to about 55 members of the class! My own 9F had to be modelled on one of these and of the locos allocated there, very few had double chimneys. 92165, 92166 & 92167 were so fitted, also having been originally built with mechanical stokers, but these had long been removed and the tenders reverted back to the BR1C type. As far as I recall, these 3 were the only double chimneyed BR1C 9Fs at Birkenhead, the others having other types of tender. Towards the end of steam by June 1968, 92167 was the last 9F in service…..so that was the chosen number for my model!


Updates might be a bit sporadic, but I’ve made a start and I’m working towards getting the boiler ready to lift off, so the smokebox can be removed to allow inspection of the area of the leak, to see what can be done. Amongst other things, I’ve got to work out how I put it all together nearly 30 years ago.....I no longer have the drawings either, having lent them to someone years ago but can't remember who. I’ll be taking photos as I go and will post a few. This one has already appeared but seems appropriate for this first post.


Hope you find this of interest….

Cheers Don

[Deleted]

Hi Don

Thank's for starting this thread, I'm sure that it will be of much interest especially as it's a little different in as instead of being a build thread it's more of a general overhaul thread. I would expect that this would be a good guide as to what's required to get a loco back in steam after not only being run for some years but also then being in storage for much more.
I look forward to reading your experiences getting this fine loco back onto the rails..

regards..

Pete

[Jim]

Welcome to the forum Don. Just to put any doubts to rest that you may have about starting a new thread let me say, we love new threads and a restoration of 9F would be great to see and along the way we'd all pick up new ideas to help us in our own builds.
I for one look forward to seeing your first posts as you start work restoring your 9F.

Jim

[pclass]

Well at least I'm not on my own now, I started to build my NSWGR 32class engine way in 1983, was going really well, boiler tested and certified in 1988, still hasn't had a fire in it, I would sy that my engine tender is somewhere around 92% completed, but it sat unloved for over 20 years while life and kids got in the way, but I'm back into it now, and recently 8th May I worked my last shift as a Registered Nurse (SRN in the UK) well I thought 50 years was long enough, cheers and good luck with your 9F a damn fine engine they are, Dennis

[ilvaporista]

Don, nice to meet you at Doncaster and I wiil be watching progress with interest.

[smallbrother]

Very glad that another loco is to be rescued. There must be thousands waiting under benches for their turn.

Best of luck and keep us posted!

Pete.

[don9f]

Hi all, thanks for the positive comments....
Firstly, when built in the 1980's, the model used a lot of 12BA hex screws to hold running boards, cladding and other bits and pieces together. At the time these were available with an A/F of approx .091 inches +/- a thou or two. I had a box spanner that fitted and I reduced its outer diameter quite a bit, to be able to reach into some awkward corners. Over time, new batches of these screws had a slightly larger hex which was around .098 inches.....probably metric size 2.5mm. Because the box spanner was now thin walled, I managed to be able to get it to fit these newer screws but when I started to dismantle the loco, it would no longer undo the original smaller ones, as in these small sizes, even 6 or 7 thou, make it a sloppy fit and the sloppiness quickly got worse.
Now this may be common knowledge I don't know, but I made some new box spanners using hex cap head bolts. 4BA (3/32 inch allen key) for the smaller headed 12BA and a 3.5mm (2.5mm allen key) for the larger headed ones. Loctited the cap heads into a bit of brass hexagon, turned the head of the cap head and some of the brass down a bit according to the wall thickness required....worked a treat. Armed with these, I soon had bits coming off all over!
Next, I wasn't sure how I'd secured the boiler handrails to their stanchions (knobs), but I think I just slid them into place and let the paint keep them there. I tried gently tapping at the ends but they wouldn't slide through the knobs without starting to distort things, so had to emery all the paint off the handrails, then they came out easily. On the full size engine, the handrails are in various sections, which cater for expansion and have joining pieces that let things slide a bit. They are secured to the knobs by tapered pins.....I didn't do that on the model as the knobs were secured only to the cladding (one piece around the boiler barrel), not the boiler itself. I didn't have any problems with movement of the handrails due to expansion.

Just for interest, between "lighting up" on a cold day and the boiler blowing off at 250psi (ie close to full temperature), the boiler of a real 9F expands by about 7/8 inch. The front of the boiler is anchored by the smokebox, so the firebox moves into the cab on these engines, as the cab structure is mounted on the frames. Allowance must be made for this when fitting the cab floor etc. so pipes and things that pass down the gap don't get squashed!

Cheers   Don

[mbrown]

I like the idea of using cap screws as box spanners - but ironmongers don't sell screws by the size of the hex wrench. Does anyone know of a quick way to discover what size screws use what size hex wrench, so that we can go and buy the right size screw to make into a box spanner for different size hex heads?

Malcolm

[don9f]

Good question....

I've got quite a few different sizes, both imperial and metric, I'll check some tomorrow and post what sizes I find.

Cheers Don

[masterdrain]

4mm metric cap head is a snug fit on a 10BA hex.

[don9f]

A quick Google found this which is a good starting point:-

www.ba-bolts.co.uk/faq.html

As shown in the table, the A/F hex of a 12BA "bolt" is supposed to be .089 inch. Not the .098 that you actually get.

Don

[don9f]

There are various tables of information on wrench, or hexagon key sizes for cap head screws of different thread sizes, if you Google. I've made a table of useful sizes as a Word Document, but haven't figured out how to show it in a post yet. Couldn't even attach it as a file this morning, says attachment limit exceeded. Will try later.
Cheers   Don

[mbrown]

Many thanks! That is enough to get me started.

As you imply, part of the problem is that commercial hex,head bolts are often made of non-standard size hex stock....

Malcolm

[Tony K]

Don, I think you have a good project here.

Would it be possible for you to post a picture of the inside of the smokebox please - particularly interested in the far end.

[92220]

For those who need the socket sizes for metric hexagon cap screws, these are the ISO standard sizes (I have only copied out the smaller sizes that would be of interest to model engineers):-

M1.6 screws - 1.56mm A/F socket
M2.0 screws - 1.56mm A/F socket
M2.5 screws - 2.06mm A/F socket
M3.0 screws - 2.58mm A/F socket
M4.0 screws - 3.08mm A/F socket
M5.0 screws - 4.095mm A/F socket
M6.0 screws - 5.14mm A/F socket

B.A. sizes for hexagon cap screws from my old British Standard Workshop Practice:

2BA screws - 0.158" to 0.156" A/F socket
3BA screws - 0.127" to 0.125" A/F socket
4BA screws - 0.0947" to 0.0937" A/F socket
5BA screws - 0.0947" to 0.0937" A/F socket
6BA screws - 0.0791" to 0.0781" A/F socket

Hope that helps.

Bob

p.s. A further range of sizes is available by using hexagon socket grub screws in both metric and BA.

[don9f]

All I can add is that some UNC cap heads I've got have hex sockets as follows:-

4 - 40,   3/32 inch
6 - 32,   7/64 inch
8 - 32,   9/64 inch
1/4,       3/16 inch

Cheers Don

[don9f]

Because of the high pitched boiler on the 9F, the fittings on top of it, ie the manifold, safety valves and clacks, mount onto pads recessed inside the barrel or wrapper. This keeps the fittings as low as possible, presumably to keep within the loading gauge etc. As I had followed the design by Les warnett, the threaded bushes on the model were on the outside, so its not possible to make a scale job of these things. I made the clacks without a dummy flange & studs to avoid them looking too high and out of place, but did include a thin locking nut, so they could be tightened into the correct position. Because they were in place before the cladding went on, the larger than necessary holes were filled in afterwards, by soldering in-fill pieces, a job that I remember was very fiddly!
I need the cladding off to be able to liberate the smokebox, but I couldn't undo the clacks without damaging the cladding (probably badly), so those in-fill pieces had to be removed. Fortunately it wasn't too bad and a fine flame and poking gadgets soon had them out.

Having removed the cab, which involved undoing a lot of pipes and disconnecting the various steam valve spindle extensions and other linkages, the manifold was unscrewed (also without a dummy flange) and the firebox cladding came off easily, revealing parts that hadn't seen the light of day for about 30 years! The cladding round the barrel is in one piece and will be taken off once the boiler is off the frames.
With a few more screws out and bits of pipe out of the way, including the injectors with their water valves, complete with brackets, it is actually now ready to lift and overall, the job wasn't as difficult as I thought it was going to be. Here are a few photos, including one of the inside of the smokebox, that TonyK asked for....hope you can see what you wanted. Most of the internals were removed after the failed hydraulic test. You can see the main steam pipe blanked off.

Cheers Don

[Tony K]

May 19, 2017 20:32:43 GMT don9f said:

Here are a few photos, including one of the inside of the smokebox, that TonyK asked for....hope you can see what you wanted.... Cheers Don

Just the job Don - many thanks.
A bit of a diversion, but I was interested in how the boiler protrudes into the smokebox. There are screws from the outside into the smokebox all around the circumference which hold the boiler in the smokebox. My experience is not extensive but I have not seen this before - all other locos I have seen have just had a snug fit between boiler and smokebox, without fixings.
It is of interest to me because, I am working on one and need to take off the smokebox - to get the screws out it seems we have to take the boiler wrapper off to get to them and possibly the cab off to get that off - an added complication if starting from a running loco. Thanks for the picture - seems to be standard then.
Back on course - a good loco evolving here Don.

[masterdrain]

Correction - it is an M4 caphead that fits a 10BA bolt head. One rogue bolt was in the M3 box and I picked it up - it's not easy being old and stupid!

Apologies

[don9f]

Well the boiler is off and the ashpan is removed.....the latter will need a good cleaning up and a few repairs, as although the stainless steel is in good order, some of my joints aren't. Problem with wide firebox models is that the boiler really has to come off to be able to get at the ashpan, so I hope to beef things up a bit before it finally goes back together. On the real 92214, one time we had problems with the bottom ashpan hoppers distorting due to heat damage (sometimes fire started in there), requiring renewal of some of the steel. It was a job that needed the rear wheelset removing on a wheel drop, then still having to work in a very awkward tight space!
My model never had dummy rocking grate actuating linkages in the cab, but having seen a friend's model 9F so fitted, maybe now it will get some.....

There are some minor dents in the cladding to attend to!





Until the running boards were removed recently, I hadn't noticed that at sometime in the past, the bracket supporting the reversing gear oil filled damper on the fireman's side end of the (rusty) weighshaft had got bent!
Les chose to fit such a damper on the model, whereas on the full size, the cylindrical part just contained a big spring....to help " balance" the not inconsiderable weight of all the valvegear hanging off the weighshaft.

You can see oil pipes running from the rear sandbox to the 10 driving axleboxes....an idea I had that worked to a degree, but the significant difference in pipe lengths meant that some axleboxes got a lot more oil than others....I'll have to give that some more thought, there are 3 sandboxes after all!



I thought there was a little bit of wear in some of the valvegear pins, particularly the combination levers, so took a few pins out to measure things. Its probably not that bad really but I made a couple of new ones just for one side today. Les's design was that the pins would be a light press fit in the fork ends and valve crossheads etc, but a running fit in the levers themselves, which are not bushed, the holes being case hardened after reaming. I don't think my efforts at case hardening did much good, as the slight wear was in these supposedly case hardened holes. I just carefully made the new pins a little bit bigger, fractionally enlarged the "press fit" holes and put the new pins in ok. The loco has probably run 100's of miles and the wear really was only slight.

Note the simple but effective tool for pressing these pins in & out.