LRM K2/2 61775 Loch Treig

[Worsdell forever]

Looking good Gus, been watching this from the start and now thinking about how to gain more clearance behind slide bars! not that there are many NER prototypes that I want to build that had them.

 

I believe that the dummy axles you are using could be part of the problem.  Any engineering locating arrangement similar to that should have tapered diameters for the connecting rods.  This takes up any slack in the rods, and ensures they are central to the axles.  I believe there was a version of this produced possibly by Rod Neep some years ago.  Also, the rod centres and frames centres should be calibrated before assembly-DJH were sometimes out, leading to erratic running and binding.

If you look at the post 2 before the one you quoted the tapered ones are being used, the LRM ones just the same as the ones I use. I find no matter how carefully a chassis is put together, with the small tolerances that we are trying to achieve some times there will be binding, after all we don't usually have instruments to measure that accurately.

[t-b-g]

When I try to watch the video I get a "This video is private" message so I can't actually see whet is happening.

 

There can only really be two causes to a slight tight spot. Rod length or quartering.

 

To check rod length, I set the wheels in a dead forward or backward position (or both - worth trying in case crank throw differs from wheel to wheel) and very gently prod the rod with fine tweezers. If there is any tightness of the rod on the crankpin at all, it is rod length that is at least part of the problem.

 

It is at this stage that "proper" engineering takes a back seat to pragmatism! If you take the crankpin retainer off the one that feels tight, you can usually see that the crankpin bush is not central in the hole in the rod, but is tight against one side of the hole. If that is the case, I simply make the hole bigger!

 

If the rod lengths are all correct and each section of rod has a small amount of play dead fore and aft, the problem is very likely in the quatering.

 

My method of checking this is to hold one wheel dead fore or aft again and to turn (gently by hand) the next one to the limit of its travel. The second wheel sould go equal amounts above and below dead level. If it doesn't, the quatering is tweaked until it does go equal amounts either side of the first wheel position.

 

Nowadays I assemble the wheels in the frames and then make the rods to fit by clamping a front and a back together with the wheels dead front/back, then lifting them away, soldering them together and addind an extra thickness for the boss at each end. So far that has given me 100% success rate. 

 

In 99% of cases with a slight tight spot, a very slightly bigger hole in the coupling rods seems to get rid. As I said, pragmatism over engineering but it seems to work!

 

Good luck,

 

Tony

Edited June 1, 2013 by t-b-g

[Rannoch Moor]

Tony and JRG,

 

Thanks for the revisit!  The paradox is the tight spot seems to have been cured (for now - construction continues!).  I did have a little tweak (as suggested by Tony) when I took off the front crankpin nuts to countersink the rod.  This seems to have sorted things for now (either that or opening out the hole did the trick...!) 

 

Back to slow progress though I'm afraid.  Today's modelling time was spent making ply scenery contour boards and applying DAS ballast to Kilbrannan Ferry (the latter to the quay side sidings) and as I am duty next week, which means I am marooned at HMS Collingwood and Fareham, then 61775 will have to do without me fr a while...

Gus

[Rannoch Moor]

Aware things have been quiet down this bearing for a while.  Have progressed some of the scenery foundations on the layout and have been sorting out the garden at weekends along with other priorities...! 

 

Picked up 61775 though last night, and all clearances have been maintained.  I fitted the backhead into the cab (cyano) so I could at least claim another step forward and now (in between the above, plus finishing my Sea Balliol and tarting up some Bachmann blue and grey Mk1 s as a late period indulgence!) the time is approaching to pluck up courage to get on with the valve gear.... 

[Portchullin Tatty]

 the time is approaching to pluck up courage to get on with the valve gear.... 

 

You do use a fair amount of nervous energy with valve gear - good luck!

[Rannoch Moor]

Thanks Mark - I will start snipping and connecting this weekend - one of my last before I move back up to Scotland permanently as I will finally say farewell to the Grey Funnel Line - at least as a serving member- at the end of the summer.

 

Hopefully my new role as an Admiralty Pilot will allow a bit more time for modelling!

[Rannoch Moor]

A bit frustrating this weekend just past.  Mounted the cylinders and motion bracket onto the chassis and then fitted the body - very tight clearances!  All well until a rolling test showed that the motion bracket was fouling the RH front crank pin.

 

The trouble was eventually traced to the bottom of the footplate pressing down on top of the bracket and pushing it down and in towards the wheels thus reducing the already tight clearance to zilch...

 

 

So, with a bit of nautical language, the bracket was removed, the top of the chassis frames filed down to be properly flush with the spacer to which the bracket is bolted.  I also (gingerly!) filed down the top of the outer part of the bracket (where it lies flush with the outer edge of the footplate) and cleaned every trace of solder from the underside of the footplate.

 

So long as the bracket is secured at exactly 90 degrees to the fore and aft centreline, that solved the problem.  I am tempted to solder the bracket on but will resist unless forced - a temporary tack may be necessary though if I can't maintain alignment as I have no space to fit 2 bolts side by side.

 

 

A final shot of the cab - still awaiting detailing which will get done after the loco is running with a full set of valve gear.  Oh, nearly forgot - anyone know if High Level supplies replacement grub screws for the axle gearwheel?  I seem to have mislaid mine which may be a bit limiting....

 

[jwealleans]

anyone know if High Level supplies replacement grub screws

Yes.  I wrote to him after one of mine pinged into oblivion and received about a dozen FOC.

[Rannoch Moor]

Back at the workbench after a bit of a break caused by holidays, change of job, and a bit of aircraft modelling to boot.  Steamed carefully into operation by actually getting grip of the valve gear - first duty was to attach the small end of the connecting rod to the crosshead by inserting a 14BA CHD screw from the rear and soldering it to a tight but rotating fit by using the crosshead arm - solderig the lot solid was avoided by using tin foil as a mask between the latter and the crosshead.  The following phot should explain further if required:

 

The union links and combination lever were then secured.  I completed the first joint using a brass lace-maker's pin, but since this seemed a little sloppy (although not critically) the rest was joined using the rather lovely stainless steel rivets supplied with the kit, any slight tightness eased by gently sliding a scalpel blade into the joint and very carefully prising out sufficient clearance.  Finally the radius rods were attached and the expansion links (the arc shaped bits) folded up.

 

I found all the holes to be correctly sized, only needing gentle clearing using a tapered reamer to establish the correct sized holes and the whole caboosh went together pretty quickly and easily although the tight clearances needed some careful handling.  Because the chassis was down a grub screw (now received from Chris Gibbon BTW - very many thanks for superb service) rolling tests were easily conducted at each stage (apologies for slightly out of focus shot):

 

The above shows the set up prior to installation of the return crank/eccentric and before securing the radius rod end to the weigh shaft ends.  The return cranks miraculously secured themselves to the Alan Gibson crankpin nut without drama and the leads were correct to my eye first stab.  While I remember to report it, the crankpin holes in the big ends of the Con rod were reamed to accept a "reversed" crankpin nut (ie so the wide end was outermost with the narrow part inserted into the con rod hole).

 

The most fiddly and challenging part of the op was to rived the small end of the eccentric to the expansion link, although the most stressful part (as ever) was testing under power!  A slight fouling by the RH lead crankpin and the motion bracket caused by knocking the latter slightly out of alignment was solved (clearances are microscopic!). Happy bunny...

 

Finally a couple of shots with the lid on... (ignore the squinty dome in the first one - the sprue stem fouled the fly wheel!)

 

[Portchullin Tatty]

You do use a lot of nervous energy up making valve gear - don't you!!

 

It is looking the part isn't it.

 

I came across these recently; have you seen them? 

 

http://www.bbc.co.uk/programmes/b00dwflc

 

http://www.bbc.co.uk/programmes/p011v806

[will5210]

You do use a lot of nervous energy up making valve gear - don't you!!

 

It is looking the part isn't it.

 

I came across these recently; have you seen them? 

 

http://www.bbc.co.uk/programmes/b00dwflc

 

http://www.bbc.co.uk/programmes/p011v806

 

They look very interesting! I also found this recently, which may (or may not) be of interest: 

West Highland Line 1960 - http://www.youtube.com/watch?v=ZHhL3xBXJFg

Edited September 17, 2013 by will5210

[Rannoch Moor]

Will and Mark - many thanks for the additional inspiration. Tonight will be construction of the pony truck I hope,

 

Gus

[t-b-g]

Looking very nice. That valve gear looks just right to me. Have you ever tried chemical blackening to stop a joint getting soldered up solid, rather than foil? I find it quite a bit easier, as I had a few problems with bits of foil tearing off inside the joint and I had to take things apart for a second try too many times!

 

Tony

[Rannoch Moor]

Given that I haven't put together an outside valve gear loco for a few years, this one went together very simply - the adrenaline must have been doing its job! The pony truck also went together very well last night despite an apparent absence of any written instructions - although I may have missed them and in any case the drawing provided gave all the detail required. I did discover though that I had no 2mm bearings to fit and (rather surprisingly given the provision of ones for the driving wheels) none were provided (unless I've lost them!), so these have been sent for from dart castings along with some MJT 2mm hornblocks ready to set up the "weighted tender" resting on the drawbar.

 

us

[Jol Wilkinson]

Given that I haven't put together an outside valve gear loco for a few years, this one went together very simply - the adrenaline must have been doing its job! The pony truck also went together very well last night despite an apparent absence of any written instructions - although I may have missed them and in any case the drawing provided gave all the detail required. I did discover though that I had no 2mm bearings to fit and (rather surprisingly given the provision of ones for the driving wheels) none were provided (unless I've lost them!), so these have been sent for from dart castings along with some MJT 2mm hornblocks ready to set up the "weighted tender" resting on the drawbar.

 

us

Gus,

 

if they are required as part of the "standard" build for the kit then they are normally supplied. An email to LRM would have provided an answer and corrected the omission.

 

Jol 

[Rannoch Moor]

Thanks Jol - suspect I've just mislaid them and they'll reappear the second that the new ones drop onto the mat below the letter box ;-)

[Scale7JB]

Hi Gus,

 

Looking mega.. Although i really can't recommend highly enough the use of chemical black when soldering together valve gear...

 

Chemical black will etch the areas of metal on to which its placed, and prevent any solder adhering to the brass/nickeld..! It really is a must!

 

JB.

[Rannoch Moor]

Needless to say, bearings "reappeared" in the bag of brass bits and the pony is now completed and secured temporarily in place - will get a snap up when I get home. Regarding the blackening JB, certainly sounds worthwhile, although much to my surprise, the rivets really worked a treat and were used in all but one of the joints this time. I have, however, dipped tweezers in the blackening stuff to prevent them getting soldered if holding things together or acting as asbestos fingers!

[Rannoch Moor]

Sorry things have been slow but I have been settling in to my new job and also taking the lucky opportunity to refurb the model room into something presentable and properly user friendly to both railway and aircraft modelling - as well as my music collection!  Here is a snap of the "man-cave"... 

 

 

As well as cracking a long progressing Lancaster and an RN DH Chipmunk (that was my first solo 30 years ago...), I have dug out Loch Treig and sorted out the floating tender and some other details, not least epoxying on the Scottish chimney, dome and the snifter valave aft of the chimney.  The complete ensemble has been road tested and as well as looking reasonably adequate (IMHO!) is running OK too.

 

 

The tender chassis has had its rear wheelset kept in fixed bearings whilst the middle and front wheels are floating in MJT 2mm bearings.  These are left with reasonable vertical and rotational freedom and the front half of the tender is weighted using a small roll of lead sheet epoxied in place under the coal space.  A hook rests on a loop soldered onto the loco drawbar which helps spread the weight load (relatively) equally on either side of the rear driven loco axle.  The loco also has a similar roll of lead sheet as far aft as possible inside the boiler in order to concentrate tractive effort. The cab roof is not soldered on yet the way!

 

 

The drawbar loop can be tweaked up and down using pliers to adjust tender ride height.  Once all secured, the smokebox front can be secured.  To ensure that this is level (as the ends of the boiler handrails need to be secured on the smokebox front...) I ran a piece of straight drawn wire through the adjacent holes for the handrail pillars (checking it was parallel to the buffer beam) ...

 

 

... and then used a wooden straight edge (trusty clothes peg!) across the holes in the front of the smokebox to ensure all was parallel before solder tacking in place as indicated by the wire in this old photo: 

 

 

Well, off to do some more...  Happy New Year to all by the way :-)

 

 

 

[Rannoch Moor]

PS The wire was actually parallel - it just doesn't look it in the phot above because the camera wasn't at 90 degrees to the line of the loco. (Well that's my excuse!)

 

Gus

[benachie]

"The tender chassis has had its rear wheelset kept in fixed bearings whilst the middle and front wheels are floating in MJT 2mm bearings.  These are left with reasonable vertical and rotational freedom and the front half of the tender is weighted using a small roll of lead sheet epoxied in place under the coal space.  A hook rests on a loop soldered onto the loco drawbar which helps spread the weight load (relatively) equally on either side of the rear driven loco axle."

Hi Gus,

Do you not find with this system that the loco rocks as the fixed axle drops into the crossing gap at turnouts?

This has been a great build - maybe more complicated than you first thought!

Alan

Edited January 4, 2014 by benachie

[Rannoch Moor]

Alan,

 

Many thanks. Haven't had the chance to run the whole ensemble through the pointwork on the layout yet although the pony (which is quite heavily weighted with lead for track-holding) didn't suffer from this. One of the advantages of EM standards perhaps? As the layout is under a snowstorm of polystyrene shavings as I progress the landscape of Kilbrannan Ferry, I haven't yet had opportunity and won't for a wee while yet but will check and see.

 

As to complexity, I saw this from the start as a potentially challenging build but although I had some prior experience of simple 0-6-0 etched locos and rolling stock (Connoisseur and Comet mainly) as well as some whitemetal outside cylinder locos and RTR conversions, this has been in some ways easier that I expected (although my obsessive reading of Rice etc over the years, and previous experience, have undoubtedly been essential). Posting on this thread has also been important - to both push my standards and to continue progress as I would hate to give up publicly! Whilst my main motivation has to been to share, I would be extremely flattered if it inspired anyone else to have a go - and particulary to support LRM or their other manufacturers by purchasing their wares.

 

I felt that Tony Wright's article series in BRM overstated some of the difficulties in this kit, and from my perspective at least, as well as shortcomings in the instructions, but I have found this kit to be well made and the instructions to be generally as logical as a complicated kit's can be. I have found Tony's articles to be extremely useful though and would recommend anyone contemplating this loco to obtain copies unless they are experienced in etched loco construction.

[benachie]

Gus,

As a fan of Rice, you will know that even his EM trackwork has an unsupported wheel gap of about 6mm which means that one of your rear tender wheels must drop by about 0.6 mm.   I believe that the transmission of the resulting rock to the top of the tender will really show up!   (I've been there.) If that doesn't  happen, then the tender suspension is not truly 3-point.   We shall see!

Alan

[t-b-g]

Gus,

As a fan of Rice, you will know that even his EM trackwork has an unsupported wheel gap of about 6mm which means that one of your rear tender wheels must drop by about 0.6 mm.   I believe that the transmission of the resulting rock to the top of the tender will really show up!   (I've been there.) If that doesn't  happen, then the tender suspension is not truly 3-point.   We shall see!

Alan

 

First time I have heard of wheels being unsupported for 6mm in EM! If I had known about that I would have gone P4!

 

 

 

I have used springing, beam compensation with a fixed axle and beam compensation with all axles moving and after trying them all, I only ever use them for something like a free tender to increase adhesion, as I find that rigid frames work perfectly well for me and I find that fitting pick ups and brake gear is easier if the wheels are not moving about.

 

Although I appreciate that others will have their own views and will tell me that I am wrong. I can live with that while ever my locos run as well as they do!

 

I have never experienced any significant degree of wheel drop through a crossing in EM, whatever method of construction I have used.

 

So I wouldn't worry about your tender arrangement. I have done that sort of thing in EM and it works just fine!

 

Tony

[benachie]

t-b-g,

"First time I have heard of wheels being unsupported for 6mm in EM! If I had known about that I would have gone P4!"

Well, the flangeway gap is around 1mm in EM so with a crossing angle of 1 in 6, the unsupported gap is 6mm. (Much worse for a turnout on a curve with lower crossing angle.)   Even for P4, the flangeway is about 0.65mm minimum with an unsupported gap of 3.9mm.   Nothing like so much of a problem with rigid or sprung.

Alan