Saint class locomotive

[Chris Higgs]

Chris,

I hope to go for a Star as the next project, and of course, a lot will be common to the Saint. The main difference will be the cylinders, so it is perhaps fortuitous that they are now separate. Perhaps it would be worth trying to co-ordinate the prihted cylinder design with etches for slide bars, crossheads and C-hangers. Any thoughts?

BTW, is the 2251 tender chassis etch available separately? Also is/will the Hall chassis etch be available and would it be worth adding Saint bits, such as steps, reversing rod, etc?

John

 

Hi John,

 

The 2251 tender chassis has not been sold alone, although as it is a different etch from the loco it can be. The original version had the frames and brake blocks, but little else, and I have upgraded it with motor mounts and outside frames based on the concepts I used with an underframe etch for the Farish Black 5/Jubilee tenders.

 

As to the Hall it is almost ready for test etch, and I have already artwork of various other chassis parts specific for Saints and Stars, such as the brake blocks and the coupling rods with the knuckle ahead of the middle driver as per prototype. But nothing which relates to the body, although that could be easily done, especially if you already have CAD outlines for them.

 

The only thing outstanding on the Hall is the C hanger, which are a bit of a pain on GWR locos. Those on the Star/Castle look even worse! It would certainly make sense to understand how the slide bars could be made to slot into your printed cylinders.

 

Having said all that, it looks like one can also convert the Dapol Hall easily to 2FS anyway, as it is split frame and only needs a set of six replacement frame bushes, the wheels, muffs and gears would then all be standard Association components. Dapol being Dapol, the six new bushes you need are different from the six you need to do the same thing on their 57XX.

 

Chris

[JohnBS]

Hi all,

So on with the fiddly bits

The connecting rods.  Ex-Peco Nickel-Silver rail with flanges filed off. Then sweated together as a pair, drilled and filed to the web profile.

After separation, flanges and bosses were added with NS shim and filed back to finished sizes. The little ends were left unfinished at this stage.

The crossheads. 10-thou NS for the front, shaped and drilled 0.5mm and a 20-thou NS piston rod, flattened at the crosshead end and drilled 0,5mm. Located with a Peco track pin through the holes and soldered together. The reinforcing ring around the front of the crosshead is 5 amp fusewire. The upper crosshead has an additional shim layer for the vacuum pump drive, yet to be trimmed to size.

Assembling the rods.  First, a keeper plate of a small piece of NS shim was drilled and soldered to the back of the con rod, again using a pin through the holes as a guide. Then the shim and the con rod were filed to their finished profiles. Finally, the components were joined, again using a Peco steel track pin with a separating piece of tissue between the Crosshead/piston rod assemmbly and the con rod/keeper plate assembly, by soldering the pin to the back of the keeper plate.

More soon.

John

 

[JohnBS]

Chris,

This all sounds very promising.

Firstly, tenders. My technical guru (son) is confident that he can produce the 3D files for the Collett tenders, with frame variations, without major work, so they could be available in the same format as the Churchward.. The could share a common split inside frame chassis, and would only need the appropriate steps etchings to complete. Would this be of interest?

Secondly, first thoughts on slidebars for two and four cylinder locos. How about two layers of 10-thou Nickel-Silver with a vertical piece joining them, to be buried in a slot in the back of the cylinder and half-etched and pressed around, and soldered to, a length of 1.0mm OD tube running through the cylinder block for additional strength and to act as a guide for the piston rod. If this looks like a possibility, I'll draw it up and send you a .jpg of the result. C-hangers are indeed a bit of a problem but slots and tabs through the frames might work, with a half-etch sacrificial piece to separate after assembly, to preserve the frame isolation. IMHO, the most important thing is to link the top and bottom slide bars to each other to keep them parallel, less important to link them back to the frames. (In the cases of my modified GF Castle and King, I merely used a small staple to do this job, see photo on 2mm finescale / GWR King / post #66, with only the top slidebar anchored back to the chassis).

Meanwhile, I will extract step and reversing rod detailed drawings and forward them to you with a PM to see if you could add them to the Hall etch.

John

[Chris Higgs]

Chris,

This all sounds very promising.

Firstly, tenders. My technical guru (son) is confident that he can produce the 3D files for the Collett tenders, with frame variations, without major work, so they could be available in the same format as the Churchward.. The could share a common split inside frame chassis, and would only need the appropriate steps etchings to complete. Would this be of interest?

Secondly, first thoughts on slidebars for two and four cylinder locos. How about two layers of 10-thou Nickel-Silver with a vertical piece joining them, to be buried in a slot in the back of the cylinder and half-etched and pressed around, and soldered to, a length of 1.0mm OD tube running through the cylinder block for additional strength and to act as a guide for the piston rod. If this looks like a possibility, I'll draw it up and send you a .jpg of the result. C-hangers are indeed a bit of a problem but slots and tabs through the frames might work, with a half-etch sacrificial piece to separate after assembly, to preserve the frame isolation. IMHO, the most important thing is to link the top and bottom slide bars to each other to keep them parallel, less important to link them back to the frames. (In the cases of my modified GF Castle and King, I merely used a small staple to do this job, see photo on 2mm finescale / GWR King / post #66, with only the top slidebar anchored back to the chassis).

Meanwhile, I will extract step and reversing rod detailed drawings and forward them to you with a PM to see if you could add them to the Hall etch.

John

 

 

OK, will await the jpg. The description has addled my brain a bit!

 

Chris 

[JohnBS]

Hi all,

The story continues.

The cylinders and rods come together.- the components for the right hand side. The con rod, crosshead and piston rod ready for fitting in the brass tube sleeve which fits through the cylinder block. The tube and rod are trimmed to size in situ and then the steel plate front cover is fixed (cyano). The short length of brass wire is for the pressure relief valve (?), fitted last.

The left hand side completed, also showing an indication of the valve actuating spindle and rocker (non-working!)

And now fitted to the frames. Rudimentary C-hanger brackets were filed-up from brass sheet and simply soldered to the frames (lots of trials and lots of errors - I wish I had thought about some tabs and slots earlier.

More later,

John

[Donw]

You make all this sound so easy John. But the pictures and descriptions are a great help.

Don

[JohnBS]

Hi all,

Just to confirm, the cylinders have now bees printed separately from the Saint superstructure, as noted above. They are also available for independent purchase - see Shapeways site

http://www.shapeways.com/shops/SteamPrint

Regard,

John

[JohnBS]

Hi all,

I haven't been totally idle but not much to post over the last few days - it's been fettling time.

Much time spent checking quartering and back-to-back, easing axle bearings and polishing the worm and gears; then on to opening-up the couplig rod holes and test running. At last, I have a relatively freely-running (but noisy) chassis and the superstructure fits (albeit the tender needs to drop down a further 0.5mm or so).

Sorry about the freeze frame shots - haven't mastered YouTube yet.

Next stages are to get some weight into the boiler, to make and fit the cab and tender steps and to fettle and fit the pony truck.Then a final check on the coupling rods before soldering on the retaining washers and reducing the crank pin projections. The front pins need to be filed back to the absolute minimum to clear the connecting rods, so no pressure!

Meanwhile, I am waiting the Mk 3 printing of the loco and tender, which should be the definitive version.

John

[JohnBS]

Hi all,
A quickie. The Mk3 final printing of the Saint and 3500 gallon tender arrived today and are looking good. Loco now has separate cylinders and backhead and additional rivet detail to smokebox. So far, brush cleaned with surgical spirit (ethanol) and ultrasonic cleaner with degreaser (Cif EasyLift) in hot water, finishing off with clean hot water. This seems effective. I guess that IPA (not India Pale Ale) would do the same. Will post pics after dusting with primer tomorrow.
John

[RichardW1]

Hi John

What do you anticipate the all up wieght will be? Will you be butting additional weight between the frames?

 

Richard

[JohnBS]

Richard,

There is an 8mm diameter roll of lead throughout the smokebox, boler and firebox with some additional lead in the firebox and copper tungsten in the ash pan.  Not much space for more in the loco but I might engineer some weight transfer from the tender if necessary to get the CofG near to the middle driver.

I have just ordered some digital scales and will post the weigh-in results as soon as possible.

John

[RichardW1]

I hope you didn't order the scales simply to answer the question!

[JohnBS]

Hi all.

Below are a few thumbnails of the final printed version of the Saint and 3500 gallon tender.

The recently-added smokebox rivet detail appears to have been worthwhile.

The cylinder block is now a separate compionent

The prints have been cleaned and dusted with primer but are (as yet) not rubbed down. The flat panels in particular will need a bit of careful work with 600 grade wet-and-dry.

Next, putting it all together.

John

 

 

[JohnBS]

I hope you didn't order the scales simply to answer the question!

Richard,

Not at all, I've been wanting to get one for ages for this very purpose and at last I have a reason to extract the digit, so thank you.

John

[JohnBS]

Hi all,

Further modest progress - the next steps (ughh!)

The cab and tender steps were scratchbuilt - two layers of 10 thou Nickel Silver sweated together, blackened with a felt pen and marked out, Then drilled for the cab step opening, filed to shape and separated.

I didn't have an unequal angle of the right size for the treads so ground off one of the webs of a length of brass T-section, to produce an angle approx 2.0 x 1.0, soldered to the NS in lengths and trimmed in-situ. On completion, the steps were cleaned and etch primed, then attached to the cleaned printed superstructure with Araldite rapid and finished with a dusting of primer.

Next - on to weightier matters.

John

 

 

 

[JohnBS]

Hi all,

Putting some lead in the pencil.

The 3D-printed smokebox, boiler, firebox and cab front were designed to take an 8mm dia weight throughout (hence the separate backhead). So, I rolled up some sheet lead, gouged out a section to clear the worm drive assembly and managed to fit in a bit more lead in the firebox, Also visible is the slug of Copper Tungsten that goes in the ash pan.

I will try to find enough CT to swap for the lead in the boiler; does anyone know if/where you can get 8mm dia CT darts?

John

PS the total weight of the loco, tender and bits already made currently stands at 70g (yes, digital scales have arrived). I expect this to go to over 80g on completion, which is about average for my tender locos.

[JohnBS]

Hi all,

The Rubicon has been crossed - there is no going back.

I have soldered on the coupling rod retainers and filed back the front crank pin to give clearance for the connecting rods. I have left temporary sleeves to retain the con rods until I have done what I can with the brake gear, but I am nervous of the very short remaining length of the centre driver crankpins. Methinks I will have to thin the bosses somewhat.

As usual. I used twist of 5-amp fuse wire to form the retainers, snipping off the "stalks" after soldering. Much easier to handle than minute washers. So far so good - all seems to be in working order

Now reunited with the Mk 3 superstructure. The bogie is also fixed, using a radius arm from a sleeve and washer on the forward keeper plate fixing screw.

I've yet to see if this will follow the track satisfactorily and how much I will need to grind off the back of the cylinders.

Now on to the means of stopping it - the brakes. Not my favourite part of loco building and particularly difficult for a loco of this wheelbase.

John

[JohnBS]

Hi all,

A little more progress. Making the brakes

I sweated together two sets of 10 thou Nickel Silver  - the first of 2 layers for the first driven axle brake hangers and shoes and the second of 4 layers for the second and third axles. Yes, even Mr Churchward had to resort to this as clearances between the first and second wheel flanges were so tight that Swindon had to devise a special hanger geometry. Then the sets were drilled, ground and filed until the shapes were acceptable, then separated to individual layers.

A simple jig was made with holes through some 3mm MDF to take lengths of 0.40mm N S rod and soldered through the hangers. The upper two jigs are shown in use. The lower left hanger is shown straight out of the jig while the lower right hanger is shown with the rod ends trimmed and ready for finished filing.

Next, the brake hangers and shoes were soldered and epoxied to the keeper plate. Similarly, the tender brake hangers and shoes where made and fixed directly to the tender chassis. The view from underneath.

From the left hand side

And from the right hand side.

The wide-awake of you will notice the absence of the rear tender brake hangers and shoes - these are almost totally obscured by the tender steps so I decided that they could be omitted.

This more or less completes the running gear, just a few details to add - balance weights, drain cocks and the final fixing of the con rods.

John

 

 

[JohnBS]

Hi all,

The latest update.

Just before last weekend's Expo, I managed to add a few details.

Drain cocks were added to the cylinders then the brake gear and cylinders were sprayed matt black. Balance weights (10 thou black plasticard) were fixed to the driving wheels - not readily visible from this side as the coupling rods are pretty near bottom dead centre. Also the vacuum pump was fabricated from brass tube and fusewire and temporarily fixed beneath the footplate. The reversing lever is from 10 thou Nickel Silver and the ejector from brass tube and rod with fusewire collars; both are temporarily fixed.

Next comes the boiler turnings - chimney and safety valve cover - and the tender flywheel. I need to clear the decks for this as my lathe normally sits (hangs?) upside down under the pivoting workbench top so all has to be cleared before I can flip the surface over. Still, it's one way of ensuring that the workbench gets tidied up from time to time.

John

 

[JohnBS]

Hi,
A bit more progress.
The workbench cleared for action.

Abracadabra, a lathe appears.

The first turning was for the flywheel. This was the most complex operation, involving two different metals, one piece of an irregular-shape, and a need to ensure concentricity/balance. Things started with a piece of 5mm thick Copper Tungsten, about 14mm x 18mm. I don't have a four-jaw chuck for the lathe but managed to lock the workpiece in the three-jaw, pushed firmly back onto the chuck face plate. Then I centre drilled and drilled out a 6mm dia hole right through and put to one side, still as an irregular shape.
This was followed by chucking-up a length of 12mm brass rod, facing-off, centre drilling and drilling through for about 15mm at 1.45mm dia (to allow for fitting to a 1.5mm motor shaft). Then I turned down a step about 5mm wide and 6mm dia - a good fit in the hole in the CT. The CT was then fitted, without moving the brass in the chuck and held in place with loctite (protect the lathe bed and anything else from drips or spray!!). The CT was then carefully turned down, working in very gently from the face until the finished diameter of 10mm was reached thoughout the whole 5mm thickness of the metal.Then, again without rechucking, the brass was cut to a cone, tapering from 10mm dia next to the CT to about 2.5mm. Finally a further 3mm straight length of 2.5mm dia was turned to form the cardan shaft socket and the work parted off.

The socket section was slit with a cutting disc and finished with a slitting file and a short length of brass rod was cut as a sleeve. Then, using a 10thou U-shaped piece of plasicard as a spacer, the flywheel was fettled to fit the motor shaft and fixed in place with loctite. Job done - phew!

The boiler fittings were somewhat easier. In each case, I produce a nice big drawing of the fittings (based on dimensions from the Russell book) with figured finished dimensions added. Although I use a CAD system, pencil sketches are just as good.
Then the fittings are turned, brass for the safety valve cover and phosphor-bronze for the copper chimney (don't even think of turning copper - too soft.) I always drill right through the fittings to allow for mounting in a pin chuck or bolting on a cylinder for finished shaping.
Here the chimney is in a pin chuck (loctite on a tapered turned-down old bolt) and the saddle to the smokebox is basically formed with a suitable grinder and finished with a half-round file.

Here the safety valve cover has been "saddled" to fit the boiler and is bolted through a mandrel (turned to suit the profile of most GWR boilers) and the flare shape is formed with a spherical dental burr or diamond ball, again finished by files. Once everything appears to be the right shape and sits tight on the boiler, then smooth with fine wet and dry and polish.

The final bits of work to the safety valve cover are to slit the base for the top feed (if any) and to make the safety valves themselves, projecting just above the top of the cover. I usually use a suitable size brass bolt with an additional slot filed acoss the head to form a cruciform, then round-off the corners of each segment,
Hey presto!

Next handrails and lamp irons
John

[queensquare]

An excellent post John on what's turning in to a model thread (no pun intended!). The Saint really is starting to display that lovely Edwardian elegance of the prototype.

 

Jerry

[DavidK71]

I dropped into Didcot Railway Centre today and a largely complete 2999 is sat in the engine shed - with the boiler in the frames, and the motion assembled, from a distance it looks ready to steam. She looks magnificent, and you've really captured the look of her.

 

Looking at the real thing, it's notable how close those front drivers are: I could just get two fingers between the two wheels at the closest point. It looks like it should be about a scale 1/6 mm ...

[JohnBS]

Thank you fort the comment; I must tootle up to Didcot and have a look.

Yes, the first and second axles are ludicrously close - I recall 6'81/2" diameter at 7'0" centres - not much space for flanges.

John

[RichardW1]

John I like your way of flaring in the chimney base. Falls into the category of 'simples'

Richard

[Horsetan]

.... first and second axles are ludicrously close - I recall 6'81/2" diameter at 7'0" centres - not much space for flanges.

 

 

Can still cause problems even in 4mm scale....but less so in P4