Rhymney Railway R class.

Discussion in 'Area 51' started by Nick Dunhill, 23 December 2020.

  1. Nick Dunhill

    Nick Dunhill Western Thunderer

    I'm building a big South Wales tank loco from a Taff Vale Models kit with some upgrades, inc inside motion and a fully detailled cab. I'm modelling no.44 which was one of the last batch of the class built by Beyer Peacock in Manchester in 1921. I think it was designated AR class as it had an upgraded boiler. Anyway, the kit has been around for a number of years, it was originally marketed by Dragon Models, but was drawn by my good friend Adrian Rowland, so I'm confident it will go together with little or no problems, other than the ones that I cause! I'm not sure whether this class of loco was used for hauling coal or passengers, perhaps someone reading this will be able to fill me in.


    So as usual I will start with the coupling rods. I will need them as a jig for positioning the axleboxes in the chassis so they're always a good place to start. The etches in the kit look good, but according to the drawing I have the rods are thicker at the bosses, and there's no overlays in the kit for these. The rods always look a bit more business-like if they have the oil filler necks and bungs, so I'll add them as well. I think the pictures are pretty self explanatory.


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    You can see I drew a right angle in pencil on the paper on my bench to aid alignment.


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    When I'm making rods I just flood the joins with solder and spend hours filing. The oil pot fillers are thin walled tube and brass rod filed into a hex (although it's questionable whether you can see the hex!)


    The next job was to fettle the slide bars and crossheads from these LGM castings. They work very smoothly now.


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    I think this is my 5th set of LGM Stephenson inside motion in the last 12 months!
     
  2. Nick Dunhill

    Nick Dunhill Western Thunderer

    I've done a few hours more fettling of castings and I now have the basics I need to make the chassis. I will make cylinder fronts and rears and the stay in front of the ashpan. The slide bars are easier to fit at this stage too together with a motion bracket and the valve rods and guides.

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    That's it until the new year. Have a great Christmas and New Year break one and all.
     
  3. NewportRod

    NewportRod Active Member

    The AR were purchased by the Rhymney for mixed traffic duties, but I think that saw more use on freight after the RR amalgamation the GWR.

    More info, drawings and pics can be found in Welsh Railway Records Volume 1 - Rhymney Railway Drawings, pub Welsh Railways Research Circle WRRC - Books

    Modellers who can only aspire to Nick's modelling abilities could try 88D's coupling rods (see 88D Model Shop Accessories Page)

    I'm looking forward to seeing future progress Nick. Are you building it in Rhymney guise?

    Rod
     
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  4. spikey faz

    spikey faz Western Thunderer

    Wow! That valve gear is a work of art. :cool:

    Mike
     
  5. Richard Spoors

    Richard Spoors Western Thunderer

    I found video 84 from the G0G library, which can be downloaded from the website, to be a very useful demonstration of how to improve basic kit coupling and connecting rods, just like Nick's above.
    Cheers
    Richard
     
  6. Nick Dunhill

    Nick Dunhill Western Thunderer

    Hi Rob, thanks very much for the info, It'll be finished as the pic below (for info only!)

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    Thanks for the kind words about the rods. The secret is to remove all the tags first then solder and flood the etching cusps. The rest is just careful filing and elbow grease. It takes me possibly 6-8 hours to make a pair.
     
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  7. Nick Dunhill

    Nick Dunhill Western Thunderer

    So as you have probably guessed the brief is to upgrade the kit with inside motion and a few other appropriate bells and whistles. If fitting inside motion it seems like a good idea to rework all the frame stays so that they're in the correct places, but retain the pair at the ends to screw the body into. So I examined the GA I have (it's a poor one, and if anyone has a decent copy I could have a sight of I'd be eternally grateful!) and drew the location of the inside cylinder front and rear on the frame.

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    Then I assembled all the components of the crank axle to decide on a suitable frame spacing.

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    The current version of Stephenson motion castings from Laurie G place the cylinder centres at 13.5 mm, which is a but less than the prototype which scale out at about 17 mm (which wouldn't easily fit between FS frame spacing anyway!) So I had a cuppa and a chat with DLOS and we had a moan about why (oh why) FS kit frames are always so narrow. The frame spacers in the kit place the outside dimensions of the frames at around 25.6 mm which is ludicrously narrow, so I decided to kick the frames out quite a lot to 27.6 mm, which will look much better and allow me to narrow the frame parts above the footplate to match without making the smokebox look too waisted. You really don't need 2mm end float on tank (or any) loco, (why oh why......) and the crank axle will fit in there without any mods to the crank webs and/or horncheeks.

    I checked the positions and mesurements (I made sure that the slide bar centres point at the driven axle centre, and nowt clatters into owt) and made some cylinders and attached the slide bars. I also made the motion bracket and attached the valve rod guides.

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    I did a cut-and-shut on the three frame spacers in the kit I intended to use, it might have been quicker to make new ones however!

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    I also made the stay that sits in front of the firebox/ashpan, and then discovered that it sits mainly on a section of the chassis not present in the kit, bah! I thought it best to modify the chassis, mainly as I had already made the stay and the bolt plates.

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    I have prepared the frames to accept Slater's brass hornblocks and formed the joggles ready to assemble the chassis tomorrow (or shall I make the ashpan first?) Decisions, decisions.......
     
  8. adrian

    adrian Flying Squad

    Not surprised - as to why - then that is just they way it's always been done - it's traditional as so it's just become accepted lore. When I started building loco's it was CCW kits etc. It was convention to use 1/4" hex brass bar cut to 7/8" drilled and tapped 6BA for frame spacers and then 1/16" thick frames gives an overall width of 1". Unfortunately the GOG technical manual doesn't provide any guidance on this - or not that I could find anyway. The only reference I could find is Eddie Cooke's live steam articles where he provides a dimensioned drawing specifying 7/8" spacing for CS (coarse scale) and 15/16" for FS.
     
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  9. simond

    simond Western Thunderer

    IIRC there are some comments about this in Iain Rice's book about etched brass kit construction, which I avidly devoured about 23 years back when I started in 7mm. I think he advocated making your own spacers, and gave some suggetions. It's aimed at 4mm but seemed a good buy anyway. I must have a look through my bookshelves again...
     
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  10. Nick Dunhill

    Nick Dunhill Western Thunderer

    Today I assembled the chassis from all the parts I had prepared over the last few days.

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    It was checked for squareness and that all was straight, then I decided to make the drag box, which will strengthen the joggle in the frames, and the ashpan to add a bit of rigidity to the chassis and disguise the gearbox.

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    I think tomorrow I'll add the cylinders, slidebars and motion bracket, and pop some axleboxes into the mix and get it all running.
     
  11. Nick Dunhill

    Nick Dunhill Western Thunderer

    So batting on, today I instaled the slidebars and motion bracket and made some cylinder bottoms and draincocks, as they're just about on view (not that I do wild-west-filmset modelling.)

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    I cut some suitable lengths of 1.5 x 1.5 mm brass angle to make the horn cheeks, as you can see I used jury axles and the rods to find the axlebox centres. You can see that I have soldered the angle in place to guide the square axleboxes. I'm hoping that the printing fairy will bring some 3D printed bolt plates to jazz up the hornguides.

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    As you can see everything is prepared now to put the wheels, gearbox and motor in the chassis and check for smooth running. Might even be some crank axle activity tomorrow, you never know!
     
  12. Nick Dunhill

    Nick Dunhill Western Thunderer

    So today I assembled the wheels into the chassis and did a whole host of other little jobs. The careful fabrication of the chassis paid dividends as the mechanism worked perfectly first time with no additional easing of the crankpin bearings (satisfying when that hapens!) The gearbox is one of Julian Wynn (Taff Vale Models) items, it's very good, and the motor is from my dwindling stash of Mashima 1833s.

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    The bogie should be a radial truck but the kit advises to make it into a bogie. I modified it to work as a radial trick with some V-shaped phosphour bronze springs to control both downward movement and side control.

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    Crank axle on monday!
     
  13. richard carr

    richard carr Western Thunderer

    Nick

    Taff Vale Models sell some very nice Mashima 1833 alternatives, when our stock does eventually run out.

    Beautiful work as always.


    Richard
     
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  14. Nick Dunhill

    Nick Dunhill Western Thunderer

    Yes thanks Richard. I have in fact used one in the past and they are indeed very good.
     
  15. mickoo

    mickoo Western Thunderer

    The 3D pixies have been busy over the weekend ;)

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    As a bit of a background to all this, Nick and I have been mulling over ways to make horn guides visually better on our models. To date you can get etched fold up ones or cast, both of which have to perform two functions, act as a working guide for the axle box and represent the actual horn guide. Each has it's ups and downs so as a trial we've split the two functions, Nick has opted for angle strip to prevent the axle box rotating and that forms the mechanical side, I've a couple of slightly different ideas on that functionality, mainly because my intention is toward the etched route.

    Having resolved the mechanical part you're now free to make the visual part look...the part....literally, these are bespoke to Nicks R class and will (hopefully) just drop over...and hide... his angle strips.

    The original idea came from the Finney7 B1 test build, in so much that I wanted a visual way to replicate the horn guides (and springs) when applied to rigid chassis construction with top hat bearings, the only way to currently do that is hack the brass cast ones.

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    These were just test ones but future ones will have a axle box fitted as well, on the reverse side will be a recess to fit over the top hat bearing in the frame. Mechanically it's a brass top hat bearing, visually it'll look like the real thing, that's the plan anyway :thumbs:
     
    Last edited: 10 January 2021 at 23:45
  16. Nick Dunhill

    Nick Dunhill Western Thunderer

    Marvellous, I look forward to fitting the above late this week. I hoped to do the crank axle thoday but got bogged down making eccentric straps fit eccentric sheaves.

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    After rather a lot of filing it was time to break out the patent eccentric rod jig.

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    But I did manage to make 4 rods in the end. Will make a crank axle tomorrow.....hopefully.
     
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  17. Nick Dunhill

    Nick Dunhill Western Thunderer

    Laurie Griffin uses a system that holds the sheaves between the crank castings using a locating pin through pre drilled holes. I found this puts the sheves in the wrong place with respect to the crankpins. Well at least I think they are, anyone had any experience of this? I ended up re drilling the individual sheaves so they were in the correct place. Next I assembled the crank etc. castings on the axle, did lots of measuring and double checking and soldered the lot up. I screwed a long screw in the axle hole and held the assembly in a vise. I put lots of paper on the floor as I was using Baker's fluid as a flux, and I didn't want it burning through to the dining room below!

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    I transported solder between the crank castings using a 100W soldering iron and then heated the workpiece very gently with a blowlamp, applying lots of flux, until the solder appeared between the sheaves. Then allowed it to cool.

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    I washed thoroughly to remove all traces of the flux. Then it's a case of filing and sanding with Wet-or-Dry paper and polishing. Here's the finished job.

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    Here it is mounted in the chassis. Everything runs very smoothly.

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    As you can see I have added the lifting links and weigh shafts and weights and trunnions etc. The expansion links are pinned to the valve rods so tomorrow I can install the eccentric rods and straps and hopefully that will be it!
     
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  18. Lancastrian

    Lancastrian Western Thunderer

  19. Nick Dunhill

    Nick Dunhill Western Thunderer

    thanks for the drawing Ian it was very helpful.
     
  20. Nick Dunhill

    Nick Dunhill Western Thunderer

    I have assembled the last few components and got the inside motion running nicely.



    Brakes tomorrow....