7mm Reworking a San Cheng / Tower GWR 1361 0-6-0ST

Isambarduk

Western Thunderer
I have been reworking a 'Tower Brass' GWR 1361 class 0-6-0ST that I bought as a non-runner from Randolph Chang when he closed down his factory.

GWR1361TowerBrass.jpg
The Tower Brass model of GWR class 1361 as received​

Actually, like so many of the models from this stable, particularly the earlier ones, the upper works are well engineered and are quite well detailed compared to the lower works, which rather let the models down, but they do all run very well. On this model, I have undertaken my usual reworkings of the motion, draw gear, vacuum and steam heat pipes and so on but the frames required quite drastic surgery to set them at more nearly the correct distance apart and to spring the driven centre axle, which was rigid in the frames. All this is a bit 'run of the mill' but I thought there might be some interested in how I made a new smokebox door.

Unfortunately, the smokebox door on the 1361 class model is quite wrong but, being part of the ‘face’ of the locomotive, it needs to be better so I decided to make a new one.

GWR1361SmokeboxDoors.jpg
The smokebox door on the model (left ) and on the prototype (right)​

I dare say that I could have found a casting, and I did make a few tentative enquiries at the G0G show at Kettering (and 'thank you' to Warren Shephard for a most helpful discussion), but I decided to make a pressing. I have done this before, but not for a door with a dished reverse curve such as this one, so it seemed like an interesting challenge. The principle is to make a punch and die with a means of restraining within it a disc of brass which is to be formed into the required shape.

GWR1361SmokeboxDoorDie.jpg
The wooden die (left) and the restrainer (centre) assembled (right)​

I machined a hole in a piece of hardwood to form the die and I turned an aluminium ring as the restrainer, which is held to the wooden die with six roundhead screws.

GWR1361SmokeboxDoorPunch-Die.jpg

I turned the head of the punch from a piece of dowel and mounted it on a steel shaft. The roughly sawn out brass disc (the blank) is firmly trapped between the restrainer and the die and the punch is pressed through the restrainer to form the blank into a dished door. Properly, the punch and die should be mounted in a press but I used my larger pillar drill.

GWR1361SmokeboxDoor15thou.jpg

For my first attempt (above), I used a blank of 15 thou (0.38mm) thickness and it was a reasonable success, but for the coggles in two places around the edge. My second attempt with a blank of 10 thou (0.25mm) thickness was as near perfect as things get in this less-than-perfect world, so I was well pleased.

GWR1361SmokeboxDoorRing.jpg
Machining the surrounding ring​

The second task was to make the thin surrounding ring. The challenge in many machining operations is getting a good hold of the job; in this case, the simplest way that I know of is to use a ‘solder chuck’: simply put, you solder the job to something that you can get a good hold of, machine the job and then unsolder it again. I soldered a ring, which I had roughly sawn out of 15 thou thick brass, to a piece of waste etch of the same thickness and screwed this to a piece of hardwood (the back of the piece that I had used earlier as the die) that I could easily hold in a four-jaw chuck. In the image (above), the inside diameter of the ring has been bored and the outside diameter is now being turned to size.

GWR1361SmokeboxDoorNew.jpg

There is a sizable hole in the front of the smokebox into which the dished part of the finished door (above) nicely fits so that the ring sits down flush on the front, centred on the surrounding rivets.

GWR1361SmokeboxNewFront.jpg

To complete the job, I reattached the hinges and made up a new set of dart handles. I modified the hinges slightly to look more like the prototype but, in the end, I decided against trying to move the lower hinge pin, which should be below the lower hinge, as there was really insufficient room for it in the correct place. This is one of the limitations of working with RTR models and kits, even very good ones; there are some design errors that require so much work to correct that it’s just not worth the effort, otherwise I would be better placed working from scratch.

So, to recap, here is the replacement door in comparison to the original:

GWR1361SmokeboxDoorOld-New.jpg

And here is what the finished front end now looks like in comparison to how it looked before:

GWR1361SmokeboxB_A.jpg

Now, you may agree with one of my friends who commented that I was nuts when I told him what I'd been up to, but it all depends what you find fun. I have enjoyed this part of the journey and I am a little closer to my final destination on this one, although there is a long way to go.

If there is interest in this kind of fun, I will be more than happy to write illustrated posts about other modifications (on this loco or on others that I have reworked, eg 8F, Black Five, Hall ...) just let me know.

David
 

Dikitriki

Flying Squad
Hi David,

I do like that. It's a big difference to the face of the locomotive. You also have a habit of making tricky things look easy!

Richard
 

AJC

Western Thunderer
Hi David,

Thanks for sharing that. Having seen one or two of these models, the smokebox area (well, and the chassis, crosshead screws and all) that most bothered me so it's good to see the changes rung. I'll be interested to see what you've done to the chassis if you've a mind to.

Adam
 

Overseer

Western Thunderer
Interesting you chose to make a die and punch to form the smokebox door. A good idea for multiple copies but wouldn't it have been quicker and easier to just turn the door from some thicker brass? Fairly easy using a round nose tool. Your close up photos show that the model has a pressed smokebox front plate instead of flat plate the prototype had, it looks odd having rivets on the front of the pressing when the point of pressed smokebox fronts (and other pressed parts) is to avoid needing the angle iron inside the joint and one set of rivets. Even the 1366 didn't have pressed smokebox fronts unlike nearly every GWR design following Churchward's adoption of them. Replacing the smokebox front with a flat plate would also give a little more space for the lower hinge pivot.

I will be watching the work to the rest of the loco with interest.
 

Isambarduk

Western Thunderer
"... but wouldn't it have been quicker and easier to just turn the door from some thicker brass?"

Yes, I take your point and I had thought of that; I have tried it before but I found it quite difficult to produce the smooth curves, so I made a pressing which I was more confident would produce the desired result. (I had thought of turning it out of plastic, which would have been easier and, after all, once it is painted, there would be no difference in appearance.)

"Your close up photos show that the model has a pressed smokebox front plate instead of flat plate the prototype had,"

Yes, and I said "This is one of the limitations of working with RTR models and kits, even very good ones; there are some design errors that require so much work to correct that it’s just not worth the effort, otherwise I would be better placed working from scratch." Actually, although I have reworked several RTR locos now, I doubt that I shall work on any more from this stable because I actually gain more satisfaction working from scratch (or using the parts from a decent kit as the basis for scratch-building).

"Replacing the smokebox front with a flat plate would also give a little more space for the lower hinge pivot."

Again, I agree but I have to stop somewhere or I would be better starting from scratch ... which is probably what I should have done but, with me, things take time so I have to compromise sometimes.

I will write up my reworking of the frames/chassis when they are complete but, in the meantime if you have not seen it elsewhere, you might like to look at: www.davidlosmith.co.uk/LMS_8F.htm , where I describe the reworking of an LMS 8F from this stable

8105b-s.jpg

or at: www.davidlosmith.co.uk/GCR_Humber.htm where I describe the my rework of a Hudswell Clarke 0-6-0ST by Ixion so that is not immediately recognisable.

GCR278-Humber-3-4-RHS.jpg

In both cases, the motion received quite a makeover.

David
 

Overseer

Western Thunderer
Sorry, I wasn't being critical of the work you have done. It just struck me that in another half hour or so a new smokebox front could have been cut out and riveted to improve the appearance even more. But looking at the photos again shows the smokebox wrapper is not quite right either so I am not sure how far I would go if it were my project. I have several kits in stagnation while I try to find the motivation to correct fundamental errors, which may expose more problems ….. Scratch building can be much easier and, I think, more satisfying.

I had seen your Hudswell Clarke which is very nice but hadn't caught up with the 8F. Impressive results.
 

Isambarduk

Western Thunderer
Overseer, Ah, no, sorry, I didn't take your comments as critical at all; please, I am sorry if my response implied that I had!

You are absolutely right about the smokebox wrapper; I should have said that I had thought about changing the smokebox front as well (but half an hour or so would be a tad optimistic for me) but then I realised that I should then change the wrapper and ... so it goes on. As far as I have seen, the largest clanger that the designers dropped was to continue the saddle tank back into the cab and to assume that the backhead fittings could be deployed all over the back of it; this really would have required that I dismantled the whole body and rebuilt it with a shorter tank and a new backhead.

"Scratch building can be much easier and, I think, more satisfying."
I do so agree, although a decent kit can be a good source of parts as a basis, as it can save a good deal of work with the coping saw (which starts to wear thin on me after a while) and some work on the lathe and milling machine (of which I never seem to tire).

Thank you for your comments re my Hudswell Clarke and 8F. Thinking about it now, I also wrote up in captioned pictures some of the mods that I made to the 8F (but didn't take photos at the time) when I did same to the LMS Black Five and Jubilee: www.davidlosmith.co.uk/LMS_Black_Five_Jubilee.htm

5663Jervis.jpg

David
 

Isambarduk

Western Thunderer
Thank you for all the interest shown here; I wrote similarly on the G0G Forum but there was no comment - to be fair, many people read my posts but there is no like button so maybe there was some interest but there was no easy way of showing it. Perhaps another bit of rather more straight forward reworking, making some balance weights, might also be of interest here.

On the model as supplied, the balance weights are the correct shape but their front faces were barely flush with the rim of the wheel whereas they should stand slightly proud of the tyre.

GWR1361WheelMilled.jpg

The first job was to mill away the front of the old balance weights (above) to make a good base onto which I could epoxy glue some new styrene balance weights. I have made balance weights before, both from brass and from styrene, by turning discs and then marking out to cut the inner arc, but I have never found the latter that easy.

GWR1361WheelBalanceWeightBlank.jpg

This time, I turned out two blank discs and, although I started the marking out, I decided to machine the inner arcs on each of the sectors.

GWR1361WheelBalanceWeightBlanksCut.jpg

I machined a shallow hole in piece of softwood that was of the same diameter as the blank discs and I then screwed a little bridge across it to hold the embryo balance weight whilst I machined the inner arc.

GWR1361WheelBalanceWeightMilling.jpg

Clearly, the inner arc is of a greater diameter than the blank disc so it was necessary to offset the piece of soft wood in the chuck by the requisite amount. The chuck was mounted on a rotary table, which was then moved to the appropriate position so that the finished balance weight was the correct width.

GWR1361WheelBalanceWeightMilled.jpg

Milling the styrene was easy and was a matter of rotating the rotary table a few times until the waste material fell away.

GWR1361WheelAndRawBalanceWeight.jpg

The raw balance weights were over length but I used epoxy to glue them in position and then I trimmed them to length in line with a spoke.

GWR1361WheelsComplete.jpg

Finally, I machined some new crankpins and bushes to suit the modified rods.

David
 

Isambarduk

Western Thunderer
Simple enough, Richard - they pulled off quite easily with a straight pull and a bit of twist. I think the reason that I was able to buy the model as a non-runner was because the wheels were not tight on their axles and the quartering had been lost; a little tweak had it running very sweetly.

To me, the next question is 'How are you going to get them back on again?'. I took off only one wheel on each axle and two of them were reasonably tight but I think the third one (the driven axle) is going to need a new insulated bush. To press a wheel back on, I put a three-jaw chuck at the lathe headstock and another at the tailstock, supporting a wheel and axle in one, and a wheel in the other. The three-jaw chucks are sufficiently accurately self-centring that the free wheel may be pressed on with the tailstock screw. I hope that explains it well enough; if not, I'll take a photo.

David
 

adrian

Flying Squad
Understood - quartering by eye?
Why not, I did it plenty of times when I was helping my Dad build locos. Wheels were frequently turned from castings so none of this fancy squared axle stuff. The wheels were finished off with a tapered reamer so we could push them half way on the axle by hand and then final press fit in the lathe the way David describes. Getting them dead on 90 degrees wasn't that critical, the most important thing was to get them all the same, we used a small drilling jig to ensure the crankpin hole was drilled consistently then when pushing on by hand it was usually a case of lining up the spokes by eye making sure each set lined up the same way.
 

Richard Spoors

Western Thunderer
David, I'm just about to embark on a similar wheels and connecting rod project, but in gauge 1. I had been planning to source my new balance weights by making some CAD drawings and getting them etched, then build up the thickness in layers. Your use of styrene seems a much better solution as I have the tools to follow your method. Taking out the old weights will be a milling challenge though as I need to get between the spokes as the new weights are not as wide at the rim.
Do you have photographs to show how you created the big ends on your connecting rods?

Richard
 

rusty

Active Member
David
I had a go at a Tower 1361 rework a couple of years ago. The smoke box door supplied looked to me to have a bit more in common with those used on the later 1366 panniers - my solution was a Laurie Griffin door but this falls short compared with your turned version. As to the chassis, wheels and motor well a complete replacement of these was my answer with just a few parts retained. Allan inside motion also came from LG miniatures but is currently out of the model pending some modifications.

Julian
 

Isambarduk

Western Thunderer
Good grief! I go out for the day (Newtown and Welshpool) and come back to find that you blokes have been busy :) Thank you for the continuing interest. So ...

Richard: "Understood - quartering by eye?"
Yes but, when I have made my own wheels*, what I do is push the wheels part way on, quarter by eye using the spokes (of course, for our purposes, the quartering doesn't have to be dead on 90 degrees, just all the same, as Adrian has pointed out), and then assemble the coupling rods and see how things run (even though the wheels are well over gauge). If there are any tight spots due to quartering, now is the time to tweak the wheels until they have been eliminated, the wheel sets may then be removed and the wheels pressed fully home. We could chat about this the next time we meet, if you wish; that way, I can wave my arms about to explain more fully.

* On several occasions, I have had to make my own wheels for small locos; I have used split axles so the brass wheels are a push fit on their axles. For 3/16" axles, I have used a taper reamer, as Adrian described, but for the 1/8" axles I have a very handy 0.124" reamer that I use to open up the holes and I then use a 0.125" reamer to open up the hole for all but the last twenty thou or so of its depth. In this way the axle will become a transition fit in the hole to allow quartering and then become a interference fit when the wheel is pushed fully home. Here are a couple of examples with 1/8" axles that I did this way:

Fowler_LHS-s.jpg

John Fowler Diesel Mechanical 0-4-0 LMS No.2
From www.davidlosmith.co.uk/LMS_Fowler.htm

AB_Calderstones.jpg

Andrew Barclay 0-4-0 Fireless Locomotive
From www.davidlosmith.co.uk/Andrew-Barclay-Fireless.htm

Richard: "Taking out the old weights will be a milling challenge though as I need to get between the spokes as the new weights are not as wide at the rim."

Hah! Yes, a 'nice' little challenge. This is how I did it when I had to remove the balance weight completely from my Ixion Hudswell Clarke, you need to be in a calm mood and to keep a cool head if you're not to make a right pilocks of it:

MillingOutBalanceWeight.jpg

I clamped a V-block to the rotary table and then clamped the wheel set in the V so that it was firmly and accurately held. Using a 2mm diameter slot drill, and by twiddling the various handles (X and Y on the milling table and angular on the rotary table) and with a clear head, I machined out the unwanted material.

BalanceWeightRemoval.jpg

From left to right i) before, ii) after milling out the weight, and iii) after cleaning up with a file and with the old crank pin milled off and drilled out.
More details at: www.davidlosmith.co.uk/GCR_Humber.htm#Wheels

Richard: "Do you have photographs to show how you created the big ends on your connecting rods?"

I have not worked on the bigends of the 1361 class yet (I may not need to do so much) but here are two from the exercise on the Black Five and Jubilee (see: www.davidlosmith.co.uk/LMS_Black_Five_Jubilee.htm#Motion)

4965ConRods-s.jpg

JubileeRodMods.jpg

and this one from the GWR Hall (www.davidlosmith.co.uk/GWR_Rood_Ashton_Hall.htm)

BigEndSaw.jpg

I made a 'stick' of bigends (turn down some nickel silver to appropriate diameter, mill a flat and silver solder on it some appropriately milled rectangular material) and the last one is shewn being sliced off the stock with a slitting saw. The larger bigends are silver soldered to the truncated conrods (shewn in the top image). I hope this is clear and makes sense (mad though it may all be).

Julian: "... a Laurie Griffin door but this falls short compared with your turned version."

Thank you, Julian.

" As to the chassis, wheels and motor well a complete replacement of these was my answer with just a few parts retained."

Well, I like a little challenge so I chopped the frames about, added extensions and then swapped them right for left, made hornblocks for the centre (driven axle) and fitted softer springs - all part of a sly and cunning plan. I'll do one of my write-ups in captioned pictures when I have it finished, if there's some interest.

"Allan inside motion also came from LG miniatures but is currently out of the model pending some modifications."

Very good! Now I did briefly toy with this but I came to the conclusion the starting point (a commercial RTR model) did not justify it and, without move the driven axle from the centre to the rear, it was a non-starter. Nevertheless, I shall build a loco with 'working' inside Allan valve gear one day; I have built working Walschaerts valve gear (GWR Castle), Stephenson valve gear (GWR Saint) and Joy valve gear (LNWR Cauliflower). The latter, especially was an exercise in precision and patience ... actually, so was the Walschaerts gear. Please do have look at the brief video clips (at: www.davidlosmith.co.uk/Valve-Gears.htm) for a slightly compulsive, mesmerising experience.

CastleBrakeGear.jpg

GWR Castle
A view from underneath​

Phew! That'll do for one posting.

David
 

Isambarduk

Western Thunderer
Amongst smaller alterations and improvements to the RTR GWR 1361 class, I reworked the cylinders. The cylinders on the model appeared rather weedy in comparison to those on the drawing and in photographs, which are rather beefy for such a small loco.

GWR1361CylindersB_A.jpg

Cylinder before (left) and after reworking (right)
I machined a spool-like core with cylinder covers at each end, around which I was able to wrap the original cladding. I was also able to reuse the stuffing box and the slidebars from the original arrangements. Although I had increased the width of the frames (and swapped them left for right, but perhaps more of that later), I had to make up a thin spacer to push out the cylinders to their correct overall spacing.

David
 

Isambarduk

Western Thunderer
Apologies that I have not posted here for quite a while. In fact, I finished reworking this 1361 class loco some months ago now, it just needs painting and reassembling. I can now finish the write-up as my new camera arrived (the first one failed to) and I have taken some reasonable images to illustrate it. My 'old faithful' Canon PowerShot A480 seems to have taken a dislike to taking close-ups with a reasonable depth of field, so it will be put on outside duties only, at which it seems quite content!

The original motion brackets were a quite unlike the massive brackets of the prototype so I drew up a dimensioned sketch and made a trial pattern in plastic before making the two parts in brass. As may be seen in the image below, I modified the design to include an additional fixing lug at the top of the bracket.

GWR1361MotionBrackets.jpg

Motion bracket: dimensioned sketch (left), original, trial pattern, replacement​

The right hand motion bracket is in place (below) and, just in board of it, may be seen the bracket to support the leading brake hanger. The vacuum ejector pump, which is mounted on the motion bracket and driven from the right hand crosshead, was not in line with the piston rod as it should have been so I corrected this and added more detail.

GWR1361VacEjector.jpg

The cylinder drain cocks that were originally fitted to the model were of a later pattern (below, left)

GWR1361DrainCocksB-A.jpg

so I made up assemblies to represent the earlier pattern (that have been reinstated on preserved No. 1363) using some castings from Warren Shephard as a basis (right).

GWR1361DrainCocks.jpg

Cylinder drain cock assemblies​

The motor and gearbox were originally rigidly attached to the frames so that, although the leading and trailing axles were sprung (with Tufnol hornblocks in guides with springs and keeper plates from above), the centre axle was fixed.

GWR1361FramesBefore.jpg

I machined up an additional pair of Tufnol hornblocks for the centre axle and arranged to spring them and to retain them with keeper plates in a similar fashion. I discarded the motor mounting plate so the motor and gearbox are now free to float with the centre axle.

GWR1361MotorGearbox.jpg

I always enclose the gearboxes on my locomotives; this was important when they normally ran on a friend’s extensive garden railway but it seems to be good practice to me anyway. I covered the unguarded gears (above, left) with a simple cover plate that is screwed to two of the gearbox stretchers and sits between the cheeks (right). The upper screw also retains a bracket to hold a pin that engages on a stretcher in the frames to provide the resisting torque for the motor (ie it prevents the motor from rocking backwards and forwards within the body but it does not impeded its rise and fall with the axle).

I reduced the depth of the frames, as they were far too deep, and I exchanged them left for right, which allowed me to push the frames out so that they were 27.5mm overall and to fit wider stretches (frame spacers). The flanges at the top of the frames, which originally turned outwards, now turned inwards and I removed all the portions that were not required to leave lugs to hold the horn block keepers and springs; not only did this improve the appearance, it allowed the motor and gearbox to fit easily between the frames.

GWR1361FramesFrontEnd.jpg

Although I needed to allow for this extra width in reattaching the cylinders, sand boxes and so on, it was not difficult and resulted in a pleasingly small gap between the back of the wheel and the frames.

Surprisingly perhaps, the GWR 1361 class has no brakes on it leading wheels so I needed only machine four plastic brake blocks and four pairs of brake hangers, and to fabricate the associated rod and plate work.

GWR1361BrakeAssembly.jpg

This assembly neatly clips over the four brackets on the frames to butt up against the remainder of the brake rods and the cross-shaft.

GWR1361BrakesAssembled.jpg

Also visible in this image are the representations that I made of the firebox washout plugs that are visible between the frames, in front of the trailing brake shoe.

With more authentic shallower frames, I was able to make up decent looking brackets for the cross-shaft and to make suitable cranks for the hand and steam brake operating gear.

GWR1361BrakesCross-shaft.jpg

On the body, other than the smokebox door, I reckoned that there was relatively little work to do. There was nothing very wrong with the original cast whistles but I knew that I could easily make better looking turnings.

GWR1361Whistles.jpg

Whereas the covers to the steam pipes had flanges at the smokebox, there were none at the running plate so, using a coping saw, I cut out some horseshoe-shaped flanges and soldered them on.

GWR1361SteamPipeFlanges.jpg

As usual with these RTR models manufactured by San Cheng Crafts, I reworked the drawgear, vacuum and steam heat pipes/hoses. Although I have described this before (see: www.davidlosmith.co.uk/LMS_8F.htm and www.davidlosmith.co.uk/LMS_Black_Five_Jubilee.htm, for example), here is the result for this loco. To provide a good key and to help hide any chips, I have chemically blackened the drawgear prior to painting.

GWR1361VacSteamheatCouplings.jpg
The representation of the reach rod and crank was a rather caricature of an affair but I improved it with a yoke at the outer end; the inner end (to the left) disappears inside the cab, so it needed no alteration.

GWR1361ReachRod.jpg
I believe that I have now covered the most interesting bits of reworking that I undertook but I would be happy to answer any questions or to clarify any points. I will post more images when I have painted and reassembled the loco.

David
 
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