Prepared by Tommy Day
Originator John H.
Thread and Forum Title 20+ years to build a pair of Fowler 4F's
Thread start date Mar 27, 2018
For full Forum thread details click here : - https://www.gaugeoguild.com/xenforo/index.php?threads/20-years-to-build-a-pair-of-fowler-4fs.1524/
Having enjoyed reading the forums for a while I notice that many of the threads in “My Workbench” seem to be about building kits. I have nothing against kits, that was the way I started in Gauge “O” but I like to scratch build, that way if there is anything wrong I know who to blame! So here goes, I am offering up for scrutiny my latest efforts. If there is any interest I will add progress as I go along. This is my first attempt at starting a thread so I hope I have done it right!
About 20 years ago I scratch built a pair of LMS Patriots for myself, which were very kindly featured in the GOG Gazette Volume 15 numbers 6 & 7. As part of the project I built 5 LMS “Old Standard” (Fowler 3500 gal) tenders using spare “Shedmaster” side etches. Two were for the Patriots, the rest for future projects. Ultimately I decided to part with one of them, the remaining two I earmarked for a pair of Fowler 4F’s. One tender was built as an early version without bulkhead doors and the vent pipes inside the coal space, the other was the later type with bulkhead doors and the vents outside of the coal space. I thought that this would give me the opportunity to build an early, Midland Railway Loco and for comparison the later, but pre-Stanier type. I had to hand a very nice set of LMS style chimney/dome/safety valves and loco mainsprings by Beeson (courtesy of the E&T of the time). This would mean I would have to make the Midland equivalents for the other loco.
The parts + tenders sat in my “to do” cupboard until last January, when I decided it was about time I completed the locos. By this time the excellent Locomotive Profiles had been published and identification of suitable details and numbers for the two locos was possible. Instead of the Midland version I had intended building, the choice settled down to an early LMS right hand drive loco, with tall chimney, washout plugs on the firebox, piston tail rods guides blanked off and a tender without bulkhead doors. The other would be left hand drive with short chimney & dome, mudhole doors on the firebox, piston tail rod guides present and the tender with bulkhead doors. From the LMS Loco profiles I was able to identify 4155 and 4547 which matched my requirements as close as I could make out.
Bulkhead door tender - messy soldering!
Early tender - no bulkhead door - must straighten those fire iron rests!
Getting back to the tenders, I discovered that I had built one compensated, the other sprung. I had also made the frames considerably thicker than I would contemplate now! However, I decided that they were good enough to use, the only real changes were to convert them to the drive system that I wanted to use. I had built a Fowler 7F in the 1980’s which used a Sid Stubbs high efficiency worm drive gearbox (it can drive back through the wheels) It had allowed me to incorporate full Walschaerts valve gear, keeping the space under the boiler clear. It is such a powerful loco that I wanted to use the same system with the 4’s and this would mean I could fit Laurie Griffin’s Stephenson valve gear. Over the years I have managed to build up a stock of these excellent gearboxes, which never got the recognition they should have from the Gauge “O” community. In fact I once picked one up from the E&T for 50p!
Stubbs gearbox - arranged to float about the rear axle.
When using these gearboxes I like to mount the motor in the tender with a decent flywheel then drive on to the gearbox with a cardan shaft. Due to the shape of the coal space the motor has to be mounted well back, so I use an extended flexible shaft, supported along its length with a mini ball race. Pick up is from the tender wheels and there are no wires needed between loco & tender.
Inside valve gear clear of gearbox
For the cardan shaft to work best it should be in line with the draw bar and the centre line of the pivots should be as close as possible to those on the draw bar. For this reason I use a draw bar with pivots at both ends rather than the more common single pivot seen in most 7mm models.
That decision made I could start on the loco frames. I have built both sprung & un-sprung locos but in this case I used a combination of “Gibson” & Slater’s axle boxes & horn guides which I thinned down as much as possible (I am not averse to using commercial castings where these are as good as or better than I can make myself) The 4F’s use a modified form of Stephenson valve gear, which LG supplies the extra parts for. As these protrude above the frames I have had to try and arrange the dummy cylinder/valve back plate so that it appears correct where it is visible.
The GA in the previously mentioned “Profile” was a big help, but no way can I get the position of the plate to align with the back of the smokebox, it has to be slightly inside. At least this means I can lift off the boiler/smokebox unit.
Progress of the superstructures was delayed again last year while I assembled a 15T rail crane for a friend, but now I am back to work on the models.
An instantly recognisable feature of Fowler locos is the cab, which has long tapered hand rails. Most of the commercially available rails are too short, as are the taper pins sold for clock makers. Fortunately I had been shown a way of making long tapers by a local clock repairer. Starting with a block of hard wood that will fit in your vice, you saw a slot, slightly deeper at one end. It should be deep enough so that a piece of brass rod when in the slot protrudes slightly. Hopefully the pictures make this clear. With a piece of rod of suitable thickness held in a pin vice and placed in the slot you file across and along while rotating the pin vice. When you have “roughed it out” to a suitable taper, the rod can be fitted in to a mini drill and polished up with wet and dry while it rotates.
The pin vice is rotated while filing across & along
The finished taper handrails
With any luck I may get the locos finished this spring and painted when the weather is warmer!
DavidL - Mar 27, 2018 at 11:11 PM
Mr H, Do you think you could post a picture of the mechanism side of the Stubbs gearbox? David
John H. - Mar 28, 2018 at 10:09 AM
Hi David, I have tried to photograph the gearbox innards as well as I can. It uses a hardened two start worm running in tiny ball races. I think Sid used the 1mm balls out of ball point pens! You have to be very careful when disassembling these boxes as they can pop out! The shaft is in a phosphor bronze bush, which also retains the worm in place, the retaining screw for this is on the other side and also serves as a location for the torsion bar. The wheel is hard brass with a pressed in steel insert to fix on the axle via a grub screw. Sid described how to make these in MRJ some years ago, I will try and dig out the issue if you are interested? I think he was persuaded to do a production run by Norman Whitnall, who did the marketing for them. I do not know how many he produced, but the highest numbered one I have is 164, I would guess at least 200. They probably seem like old technology, but are a vast improvement on the basic single start worm gear sets. The gearbox is almost totally enclosed with a tiny oil hole in the top. I like the fact that you can push the loco and the wheels go round with these boxes! Regards to all,
John H
DavidL - Mar 28, 2018 at 1:23 PM Many thanks for taking the trouble to disassemble and photograph the box. It certainly seems well made. I count 45 teeth, so if that is a 2-start worm it would have an overall ratio 0f 22.5:1.
I'm surprised, and rather impressed, that it will work in reverse. you'd normally expect something more angled than a 2-start worm to achieve this. Are the teeth on the gear cut straight or helical? David
John H. - Mar 28, 2018 at 1:57 PM I guess that the precision that Sid employed helps plus the fact that the parts are polished and use the tiny bearings. Anyway, I dug out his original article in MRJ, which was No. 42 pages 591-594 entitled “High Efficiency Worm Drives”. He goes in to the theory in great detail, with calculations etc. which leave my head swimming! He also details the tools used in their construction with diagrams & photos. He made two types suitable for gauge “O” , the smaller one he only recommended for use in shunters as it was originally designed for 4mm use, but I have it in my L&Y “Ironclad” and it will pull 50 coal wagons no problem! I suggest locating the article if you are interested, it is very detailed. Both types in my locos are driven by Mashima 1833's which seem well up to the job. Hope this is of interest, regards, John H.
DLOS - Mar 28, 2018 at 9:10 PM I have often made tapered handrails this way, although I put the piece of wood in the tool post in the lathe and the wire in the headstock chuck. If the handrails are to have a polished finish, I use spring steel (piano wire), reducing the diameter with a stone or diamond lap. David
John H. - Apr 3, 2018 at 4:21 PM
Got those long handrails fitted at last. It was an interesting exercise to make them pass through the cab side beading. I did it by drilling the beading 0.5mm then used a piercing saw to elongate the hole. When I thought it big enough I forced a tapered scriber through to make it round. The brass was soft enough to take the shape without breaking. After the half round bead was soldered in place I used several tiny washers above & below to simulate the fixings of the real thing. The cab top anchorage point was made using tiny turnings which were then flattened at the inside & outside before soldering all up. The bottom of the taper handrails is not fixed but pushes in to holes in the footplate so I can remove the cab for painting.
Now that both cabs are to this stage I can progress with the backhead details. I have not been able to track down a supplier of castings for these so most parts will have to be fabricated. I have some “Microcast” Dewrance water gauges and MR regulators so these will be ok. I also have a couple of Slater's driver's brake valves which will do with a bit of modification. The GWR firehole door levers produced by Warren Shephard are almost right so again a bit of “cut & shut” saves a lot of time!
Now back to the soldering iron!
Haines10259 - Apr 4, 2018 at 9:57 AM What did you make the bands retaining the cladding on the firebox from John? They look very neat and I'm wondering how to do them on my 4-4-0. Very fine detailing on the cabside there. It is surprising how visible tiny stuff like that is even from a distance - something to do with lines being broken up where they should be I think.
John H. - Apr 4, 2018 at 3:22 PM Hi Dave, the boiler bands are some phosphor bronze strip that came from the estate of my late friend Mike Hart - I do not know where he had them from. I have some similar nickel silver strips courtesy of Tony Reynolds but they are a little broader and I find it easier to line them up when they are in a different colour. I found these Fowler cabs a bit harder than the ones on my Patriots & Scot - perhaps to do with the fact that they are narrower? They looked ok when I did the beading & rivets but when I married them to the firebox & footplate I can see that all is not perfectly square. The photo exaggerates the appearance too! The locos are built in modules: footplate /smokebox+boiler+firebox/ cab /backhead/cab floor+seats+reverser, so it should tighten up a bit better after painting.
Hi John and Dave For boiler bands I use Slater's phosphor bronze pick up strip (catalogue no. 1220) which is only 5 thous thick by 1/16 inch wide. It's probably a bit too thick and wide to be exactly to scale but when it's been painted over it looks ok to me.
Haines10259 - Apr 4, 2018 at 5:04 PM Thanks Bob and John - I have some of the Slaters strip which I use for pickups - I'll try it for the cladding bands on the firebox.
John H. - Apr 18, 2018 at 8:59 PM
There comes a moment in any scratch build where there is the need to make a bunch of identical components. With two 6 wheeled locos I need 12 brake hangers, which must all have the same dimensions from top hanging point to bottom pull rod and need also to accurately line up at the pivot point of the brake shoes. Not having access to a pantograph miller (or the skill to operate one!) I have to use a tried and tested method along with hand tools. Probably everyone is familiar with this method - I was not until I was shown it about 20 years ago. Starting with two strips of ground, flat steel stock (gauge plate) just a little longer and wider than the dimensions of the hangers, I scribed a centre line along one piece. Allowing for the material needed at the top, I centre popped the position of the top & bottom fixing holes. I did the same for the fixing for the brake shoe, in this case I am using Slater's plastic ones. I then drilled these markings out using a 1mm drill. I clamped the two pieces together and used the pilot holes to accurately drill the second piece. Leaving the brake shoe hole at 1mm on both pieces, I then tapped 12BA one of the pieces, the other I drilled 12BA clearance. This allowed me to accurately fix both pieces together and then profile them to the shape of the brake hanger.
The next step was to harden and temper these pieces so that when used as a filing guide they would retain their size and shape. I then prepared a set of 0.7mm nickel silver blanks, slightly longer and wider than the finished item and drilled them all at one end. Using the clearance drilled one, I was able to accurately drill the second hole so that I could clamp each piece between the formers.
Then it was down to the boring job of filing each piece. I found that I could just get away with doing 2 pieces at a time and speeded up progress accordingly!
While the pairs of blanks were clamped together I drilled the 1mm hole for the brake shoe.
All was going well until the last pair when the inevitable happened! I had not properly tempered the tool after hardening it!
At least it waited until I had nearly completed this stage. Next job is to make the 6 cross beams and silver solder some 12BA studding in the ends - but that job is for another day.
John H. - May 16, 2018 at 2:07 PM
Slow progress on the brake gear with a fair bit of silver soldering needed. The brackets for the brake hangers I used some square section tube, drilling and forming to the required profile and silver soldering little spacer bushes behind the hangers. the brackets could then be soft soldered to the loco frames and the holes in rear of them tapped 12ba to fix the hangers:
The cross beams were shaped from some N/S and short pieces of 12ba studding silver soldered in to the ends to connect with the bottom of the hangers. The pull rods are not quite as per prototype, the adjusters for these were made from some square section brass rod, turned down for a few mm then drilled 1 mm to take the 1 mm N/S pull rods. the pieces between the intermediate wheels were slotted so that the cross beams could pass through.
Last bit of the jigsaw is the brake cylinder bracket and levers, omitting the cylinder as the model gearbox takes up the space where that should be. Next job should be the fall plates between loco & tender, something more satisfying at last!
Stenner21772 - Jun 11, 2018 at 7:49 AM Can I firstly apologise for coming late to this thread, echo John's comments about the dominance of kit building (absolutely fine and wonderful as it is) on the Forum, and say how good it is to see the standard of workmanship depicted; I well remember John's articles on his 'Patriot' locos and the highlight they were in those editions of GOG Gazette. Secondly, could I endorse everything John says about the Stubbs gearbox and echo his comments that they were seriously under-appreciated in their time. As an aside, we both had a mutual friend, now unfortunately deceased, who used to describe us both as 'Stubbs gearbox fanatics.'(!) Thirdly, Graham's comments that the boxes don't drive back. You have to do some 'running in' to get this feature to work. For the 6 boxes I have fitted in locos, I started by using a 3/16“ drill or reamer shank as an 'axle' through the gearwheel. Holding the 'axle', it is then possible to start to work the box backwards and forwards gently around the axle, noting that the input shaft will start to revolve a little. Some time spent doing this starts to free things up and the box starts to 'drive back', but I've found that absolute smoothness won't be achieved as yet. So, over to machinery, and subject to all the usual safety considerations needed with even small workshop machinery, place the 'axle' in a drilling machine or lathe chuck, secure the body of the box to stop it revolving, put a small amount of light oil in the box and run the machine for a few minutes in each direction. This usually frees things still further, and running a loco on a layout at a couple of exhibitions completes the job. Like John, I have used the boxes in three tender engines all with the motor tender-mounted and drive shaft below the footplate in two cases, and above in one. The small Victorian locos I model can make locating the box difficult, and I've most often had to go for the centre axle on 6-coupled, front axle on 4 coupled; the low footplates on the
John H. - Aug 13, 2018 at 1:00 PM
The end is in sight!
Just finished painting the two locos, only waiting now on the smokebox number plates, which will hide those 10BA screw heads. Still need to find some perspex material for the gauge glasses on one loco having lost the original material while trying to cut to length! I also need to find some means of attaching those superb “Beeson” loco mainsprings, which need to be removable so as to get at the screws retaining the axleboxes. Initial testing has shown a few shorts, which surprised me as they ran fine unpainted. Anyway, here are some photos for critique/comments.
Hope these are of interest, regards to all, John
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Powell2517 - Aug 13, 2018 at 3:26 PM Very very nice. Beautiful models. rgds Graham Powell
Martin Long - Aug 13, 2018 at 3:38 PM Lovely work thank you for sharing. I was also encouraged that you also show solder where it perhaps should not be which is the typical case for me too! This sort of posting greatly encourages the ham fisted ones amongst us and I am very grateful for showing us your efforts. Thank you Martin
John H. - Aug 13, 2018 at 4:43 PM Thanks Graham & Martin! I consider myself a very “Ham Fisted” modeller but am much encouraged by the kind comments. Yes, I do get solder where it should not be but my models are meant to be painted and as long as the surface is just “tinned” by the solder and not lumpy the paint will still stick. This is my first attempt at painting with acrylic “Rattle Cans”. The primer went on great, the topcoat was ok, but the methsfix transfers were a pain, lifting at the slightest excuse. I helped them down with a thinned down varnish, but that left a “halo” around them, so I decided to give the locos a complete varnish. First coat went on and looked grainy, so I gave another, well thinned down. Even worse! Finally I tried again with some matt varnish, which at least looked uniform and I can suggest the locos are in typical grimy goods livery! Smoke box number plates arrived this afternoon from “Guilplates” & look very nice so that is Wednesdays job along with fettling the running. Regards, John
DavidAtkinson4172 - Aug 13, 2018 at 5:18 PM Hi John In no way do I wish to denigrate your models. I think that they are superb but, one of them is carrying the same number as Lima's offering, No.4547. Is this intentional or a way of fooling onlookers? I can take more than 20 years to do a model and it isn't finished yet. I started it in 1978. David A
John H. - Aug 13, 2018 at 6:55 PM H Folks, thanks for all of your kind comments. The choice of numbers was occasioned by the need to have one LH drive, the other RHD, a tender with bulkhead doors, the other old style without. After trawling through loads of photos I finally settled on these numbers as there were photos of both in the LMS loco profile series & supplement. I did not realise that I had duplicated the Lima one but hopefully mine is closer to the prototype! As to the time, I thought that leaving the tenders without locos to pull them for 20 years was way too long. Regards, John
John H. - Aug 22, 2018 at 4:55 PM
The Final Chapter!
I could not bring myself to modify those jewel like Beeson mainsprings to fit the locos. Besides which I only had one set, so thanks to the help of a well known kit manufacturer I was able to have some excellent copies made.
Rather than use the Beeson fixings at the outer ends of the springs, I modified the copies to take a “T” shaped piece of brass. These are threaded 13BA (only 'cos that was what I had to hand) and then I soldered the brass pieces to the keeper plates of the hornblocks. This allows the springs to be removed via a screwdriver poked between the spokes of the wheels. Once the springs are removed access to the retaining screws of the hornblocks is possible.
A few dabs of black paint on the exposed parts and another check to make sure there are no shorts and it is “Project Complete”
Well almost - when I came to fit the crews my superglue had gone off so that is a job for when I have bought some more!
Incidentally, I had some extra sets of springs cast so if anyone is interested????
Regards to all, John H.
