LNER A6

[N15class]

Now I think I might just try that! I must confess that my dislike of floating gearbox/motor combinations was based on experience with the Q5/2 kit, where the motor's torque tended to rotate the motor/gearbox. That said, a motor/gearbox fitted to a fixed driving axle, will also attempt to rotate if there is any binding, even slight binding, on the motion or if the gears are not correctly meshed and properly run in.

 

There you go, Bill, thanks for the comment.

 

Cheers

 

Mike

 

When I use a motor and gearbox I use a torsion wire between gear box and chassis. this will stop the unit from rotating and still give the it flexability to float. I also use the same on a rigid mounted unit, as I dislike the motor being fixed solid.

[mikemeg]

Having now started the chassis for Arthur's A6 kit, I then decided to revisit the chassis for my earlier scratchbuilt A6. Arthur did send a complete chassis etch, for this build, in advance of sending me the full A6 kit for trial build. Originally I had intended to use the earlier scratchbuilt chassis just with detail additions from Arthur's etches.

 

On reflection, however, (that's a euphamism for me deciding that I was being just 'bloody daft'), I decided to completely replace the scratchbuilt chassis with Arthur's etches. Somewhere else on this topic area there is a discussion on the merits and definition of scratch building in 2012. My contribution is, therefore, that I decided that Arthur can 'etch em' better than I can 'measure and cut em'. There is no satisfaction, at least for me, in opting to do it myself when there is a much easier and more accurate way and one which provides much better results.

 

So another two sets of articulated A6 coupling rods were kindly supplied by Arthur and assembled. These were then checked for consistency in the chassis jig (and they are) and then the first mainframe located in the jig for fitting the High Level hornguides and axleboxes. The top hat bearing, in the leftmost position is merely there for setting up in the jig and will now be sawn out and a hornguide and axlebox fitted as per the other two axles.

 

Both chassis will be sprung on all three axles using CSB's. The locations for the CSB fulcrums (fulcra?) are already half etched on the inside of the mainframes.

 

These chassis jigs do seem to make life very much easier when positioning the axle bearings in the frame and in ensuring consistency of spacing between the coupling rod and the axles; not to mention keeping everything square during the chassis assembly.

 

Now to do the same operations on the second A6 chassis.

 

Cheers

 

Mike

[Horsetan]

.....(fulcra?)....

 

I think that's a village in Ireland.

[mikemeg]

I think that's a village in Ireland.

 

Horsetan,

 

Did you see that the inhabitants of 'Effin', which is also in Ireland, cannot register their address on Facebook? Apparently the Facebook 'rude word filter' removes this address element.

 

Wide and varied are the subjects which come up on this site.

 

Regards

 

Mike

[Horsetan]

Horsetan,

 

Did you see that the inhabitants of 'Effin', which is also in Ireland, cannot register their address on Facebook? Apparently the Facebook 'rude word filter' removes this address element.

 

"Ephin" would work, though!

[mikemeg]

I had planned to clip and trim forty odd yards of beech hedging, today, but the weather has intervened and put a stop to that. So the A6 chassis' can receive some attention. I've completely remade the chassis for my scratch built A6 body driven on the front axle. Getting those rods to revolve sweetly was a b----r of a job, though they do now run as they should. My yardstick, with 50 : 1 gearing as this chassis is, is for wheels to complete one revolution, without binding, in > 10 seconds and this one will, in forward and reverse. I did find that the optimum fit for the rods was with the absolute minimum of slop at the journals, perhaps around 5 - 7 thou.

 

The second A6 chassis; the one intended for the trial build of Arthur's kit has now been fitted with CSB's and has been assembled in the chassis jig. So far only the free running of the 1/8" axles within the axleboxes has been checked. So now to fit the crankpins to the wheels, assemble the driving wheelsets and then check the assembled wheelsets for free running. Before I do any of the adjustment of the rods, I'll prime and blacken the frames; at least those areas which will be obscured by the driving wheels.

 

You may notice that Arthur has revised the shape and design of these mainframes, along with the rear radial axle on the later version, compared with the earlier version. There are other changes made to the chassis etch around the brake hangar brackets and body fixing locations.

 

Cheers

 

Mike

[mikemeg]

The rear radial axle and truck has now been assembled and checked to ensure that it keeps the rear radial axle in contact with the track, which it does. This is a really very nice piece of design with a very simple springing system which provides both vertical springing and lateral springing, all with just two wires.

 

Last jobs, for today, are to check the gearbox fits between the frame spacers, which it does and to start loading the chassis with weight to check the springing deflection and hence ride height. So far this has 100 g on each end and deflects around .5 mm, though on only four wheels. This will be repeated with 150 g each end and finally 200 g with all six wheels just fitted and gauged, then removed. This also allows the individual axle springing to be checked, simply by rocking the chassis from side to side and end to end.

 

This kit is designed to utilise one of the High Level gearboxes; I just happened to have an unused Comet 50 : 1 two stage box which I therefore decided to use, as also on the first of the A6 chassis.

 

Cheers

 

Mike

 

 

Cheers

[mikemeg]

So I now have a working chassis for one A6 and an assmbled chassis for another. The A6 body kit is awaiting the production of the final castings - NER smokebox door, chimney with capuchon, sandboxes and a couple of others; the scratch built body is now awaiting priming and painting. Also need to build another front bogie; I only have one shared between the two locomotives.

 

There's something about the bare metal, especially nickel silver.

 

Cheers

 

Mike

[Paul Cram]

Can we see a photo of the radial axle and springing please?

[ArthurK]

Paul

 

It isn't a radial axle but a swinging truck. I decided that was an easier solution. This truck has an upstand to take two spring wires. The wires have fixed anchor (fulcrums) in front and behind the truck. these are arranged so that the holes in the truck are lower than those that are fixed so placing the model on the track puts a downward pressure on the truck. In a similar way there is a centering force when the truck is pushed sideways. This is a new idea of mine. I am waiting to here from Mike to see if it works in practice. Initial results suggest that it does.

 

ArthurK

[mikemeg]

Paul

 

It isn't a radial axle but a swinging truck. I decided that was an easier solution. This truck has an upstand to take two spring wires. The wires have fixed anchor (fulcrums) in front and behind the truck. these are arranged so that the holes in the truck are lower than those that are fixed so placing the model on the track puts a downward pressure on the truck. In a similar way there is a centering force when the truck is pushed sideways. This is a new idea of mine. I am waiting to here from Mike to see if it works in practice. Initial results suggest that it does.

 

ArthurK

 

The swinging truck works very well on the track, though so far I have only pushed a 'dead' chassis along the track. Nonetheless, the springing holds the wheelset on the track and does allow for any vertical inequalities (and there are a few on Hessle Haven's trackwork) in that track. So, the swinging truck 'passes muster'. As the ruling curves, on Hessle Haven, are the radii of a B8 turnout, these do not really cause much lateral deflection on the swinging truck but I would think it would happily traverse curves of < 3 feet radius, possibly less with the narrower frame spacing provided for EM and OO.

 

I've now assembled the gearbox and motor for the second A6 chassis, this time driven on the centre axle. There does seem little point in not driving on the centre axle unless a flywheel is to be used; I drove the first A6 chassis on the front axle simply to see if and how it could be done.

 

So, now for the second bogie and then some of the 'furniture' which adorns the frames - brake hangar brackets, brakes, brake linkage, slide bars, etc. And I will need to take the slitting disk to that front motor shaft, taking care to avoid cutting off the motor terminals!

 

Getting the rods to revolve sweetly, on the second chassis (driven on the middle axle) was only slightly easier than the front axle driven chassis. Anyway, both now run as they should.

 

Cheers

 

Mike

[clecklewyke]

Can we see a photo of the radial axle and springing please?

 

And the suspension of the bogie, please?

 

Ian

[ArthurK]

Normally I would let the bogie take a small percentage of the loco weight but with a filly sprung loco I am entering new ground. The bogie itself is fully compensated on hinged beams. Some form of springing will have to be adopted. I am experimenting with a sprung/compensated bogie. Mike has a difficulty as the A6 bogie does not have the spring/compensation beams so prevailent on most NER bogies. Because of the fitting of bogie brakes in late NER days coil springs were used instead. Any springing on the model will have be carefully hidden inside the frames and there is not a lot of room in there!

 

ArthurK

[mikemeg]

What I have done on the first of the A6 chassis is to elongate an 8BA bolt, by joining two 8 BA bolts together after removing their bolt heads, and then re-inforcing the joint with a nut at a height where this nut will engage on the underside of the footplate when the chassis is bolted to the body. This is used to fix the chassis to the body where it bolts into an 8BA nut soldered onto the footplate, inside the smokebox.

 

This elongated bolt also fits into the cross stretcher on the bogie. The bogie is then held on this by an 8BA bolt under the cross stretcher. The hole in the bogie stretcher is elongated, slightly, to allow for a little sideways movement of the bogie as well as the normal rotating movement as the loco encounters curves. As I've said, above, the ruling curves on Hessle Haven are those found on a B8 turnout so this movement is very small.

 

The whole bogie is sprung with a spring between the top stretcher of the bogie and the underside of the stretcher across the mainframes and this spring is entirely hidden inside the mainframes. This allows the bogie to follow the track contours both fore and aft and from side to side, as the spring is not a tight fit on the bolt.The spring has an 8BA washer soldered to the bottom of it to prevent the spring sliding into the slot on the bogie cross stretcher. The extent of the springing is therefore controlled by the length of this spring and the extent of its compression when the loco is standing level.

 

I'll use a similar system on the second chassis, though slightly modified, as Arthur has modified the front chassis/body fixing location on this latest version.

 

I'll try and photograph the components of this system as the light improves; at the moment it's dark, grey and raining.

 

Cheers

 

Mike

[davec.hh]

Mike,

 

Would 8 BA studding have been better than elongating a bolt?

 

DaveC

[clecklewyke]

Thanks, Mike.

 

Your description and photos make it quite clear how the bogie itself is suspended. I suspect I will do the same on my 2-6-4T, as arranging amy equalisation of it in conjunction with the drivers would just add complexity. (Which engineer was it who recommended adding simplicity?)

 

From the photos it seems that within the bogie there is no suspension, i.e. the bogie is rigid, which will be fine if the quality of design and construction is good, which I am sure is the case here. I might be tempted to equalise the axles on my bogie, because I am not confident that I could do so well.

 

Ian

[mikemeg]

Thanks, Mike.

 

Your description and photos make it quite clear how the bogie itself is suspended. I suspect I will do the same on my 2-6-4T, as arranging amy equalisation of it in conjunction with the drivers would just add complexity. (Which engineer was it who recommended adding simplicity?)

 

From the photos it seems that within the bogie there is no suspension, i.e. the bogie is rigid, which will be fine if the quality of design and construction is good, which I am sure is the case here. I might be tempted to equalise the axles on my bogie, because I am not confident that I could do so well.

 

Ian

 

Ian,

 

Yes, within the bogie itself, there is no equalisation or suspension; the bogie is rigid. As Arthur mentioned, above, NER bogies did, normally, have compensation beams on them which Arthur has faithfully reproduced, to work, where they were present i.e. on his D20 chassis. The A6 bogies, latterly, used coil springs, which are nigh on impossible to reproduce in a working fashion.

 

So, as this bogie is rigid, then the whole bogie is sprung, so I did try and assemble this bogie as square as I could. I also introduced a little slop in the axle bearings for the bogie; after all there is nothing dependant on the relative position of these axle bearings other than their allowing all of the wheels to maintain contact with and stay on the track.

 

The other thing I did was to ensure that there was a minimum of lateral slop on each axle, so the gauging of the axleboxes is such that they allow only about .010" of sideplay on the wheelsets. It is the springing of the bogie frame, itself, which follows the curves and track height variations and forces the wheelsets onto the track.

 

If your 2-6-4T is a P4 conversion of a r-t-r model, which I think it might be, then you will have a bar joining the central bogie fixing to another point further in from that first fixing to allow some eccentricity on the swing of the bogie; this to allow for the very tight curves which r-t-r models are designed to traverse. You might, therefore, need to modify that arrangement in order to spring the bogie. Or, are you planning to make a new bogie to replace the original r-t-r fitting?

 

Hope this helps, my old friend, but if not then just keep posing the questions.

 

Cheers

 

Mike

[mikemeg]

One of the things I did wonder, on this A6 kit, was whether the mainframe cut-outs for the bogie wheels were too large, even given the allowances which have to be made for the slightly larger flanges on OO wheels. One always imagines that these cut-outs were designed to just clear the wheel rims by an inch or two.

 

So, a quick consulatation of some prototype photos, just to have a look. This is 69796 parked in Botanic Gardens shed in Hull, sometime after mid-1950. And no, Arthur has it just right, there is quite a gap.

 

Cheers

 

Mike

[ArthurK]

name='mikemeg' timestamp='1339758402' post='715110']

One of the things I did wonder, on this A6 kit, was whether the mainframe cut-outs for the bogie wheels were too large, even given the allowances which have to be made for the slightly larger flanges on OO wheels. One always imagines that these cut-outs were designed to just clear the wheel rims by an inch or two.

 

So, a quick consulatation of some prototype photos, just to have a look. This is 69796 parked in Botanic Gardens shed in Hull, sometime after mid-1950. And no, Arthur has it just right, there is quite a gap.

 

Cheers

 

Mike[/b]

 

I took the profile of the cutouts for the bogie wheels from the GA of the A6. A small point, but worth saying, is that the bogie wheels that I use are Gibson 3' diameter rather than prototype 3' 1 1/4" as on the real thing so we have gained nearly 0.5mm there. I think that Mike uses the same wheels. The Romford style 3' wheels may need the frames to be opened out a little.

 

ArthurK

[clecklewyke]

 

 

If your 2-6-4T is a P4 conversion of a r-t-r model, which I think it might be, then you will have a bar joining the central bogie fixing to another point further in from that first fixing to allow some eccentricity on the swing of the bogie

 

In fact I am planning to replace the Hornby chassis - it's pretty crude but with Gibson P4 wheels has given me a useful loco for the past few years. I have a Perseverance chassis for it and this will be the first chassis I will have built with both leading and trailing bogies or ponies. Having just a leading or a trailing pony or bogie is quite easy (I've successfully built 0-4-4, 4-4-0 and 0-6-2 chassis) but I think wheels before and aft of the drivers, such as a 2-6-4 or 4-6-2 will be an interesting challenge.

 

Ian

[mikemeg]

I took the profile of the cutouts for the bogie wheels from the GA of the A6. A small point, but worth saying, is that the bogie wheels that I use are Gibson 3' diameter rather than prototype 3' 1 1/4" as on the real thing so we have gained nearly 0.5mm there. I think that Mike uses the same wheels. The Romford style 3' wheels may need the frames to be opened out a little.

 

ArthurK

 

I seem to remember reading, somewhere, that locomotive driving wheels could be anything up to 2 and 1/2 inches less than their nominal diameter before they were re-tyred and restored to that nominal diameter; this through normal wear and through tyre re-profiling which was done at the larger sheds, as required, and at the works during overhauls. I imagine that bogie wheels and tender wheels also lost diameter, through wear. I don't know whether it was common works practice to re-tyre bogie wheels and how much tyre wear was incurred before such re-tyring was done but a 1 and 1/4" reduction in diameter would certainly be present on driving wheels.

 

In fact, at the maximum loss of diameter on the driving wheels (2.5 inches) the whole locomotive would surely ride some one and a quarter inches lower, which, with carrying wheels at their nominal diameter, would close the gap between their rims and the mainframe cut outs or is this assumption just wrong? The reverse should also be true i.e. driving wheels at their nominal diameter, carrying wheels heavily worn.

 

I guess all of this means that the diligent search for 4 mm wheels of exactly the right nominal scale diameter isn't absolutely necessary.

 

I also imagine that this reduction in wheel diameter, especially on smaller wheeled locomotives i.e. 4' 81/2 " could materially affect their tractive effort. as this calculation has the wheel diameter as a factor.

 

Cheers

 

Mike

[mikemeg]

In fact I am planning to replace the Hornby chassis - it's pretty crude but with Gibson P4 wheels has given me a useful loco for the past few years. I have a Perseverance chassis for it and this will be the first chassis I will have built with both leading and trailing bogies or ponies. Having just a leading or a trailing pony or bogie is quite easy (I've successfully built 0-4-4, 4-4-0 and 0-6-2 chassis) but I think wheels before and aft of the drivers, such as a 2-6-4 or 4-6-2 will be an interesting challenge.

 

Ian

 

The only advice which I can offer, on building a chassis with carrying wheels at both ends as per a 2-6-4, is to ensure that the locomotives centre of gravity lies over the driving wheels; ideally over the centre set. This does at least allow the springing of pony trucks and bogies to be limited to just enough downwards force to keep the wheels on the track. A fully sprung chassis might slightly alter that dynamic, especially if the springing forces differ across the front and rear axles.

 

Cheers

 

Mike

[mikemeg]

The various castings arrived through the post, so now I can start the detailing process which should make the model begin to look like a locomotive. Though these castings have a 1/8" stem on them (chimney and dome), I normally remove this and then very gently file the bottom of the casting on an 18 mm or 20 mm diameter former around which is wrapped very fine emery paper; this just to get the seating on the boiler good and snug.

 

The chimney on this is based on the Q5 chimney, though I did do a little surgery on it, including adding a tiny bit to its height and adding a capuchon. The smokebox door fitted to this loco, even in its final days, is the original Class W NER smokebox door. Several of the class continued to carry this original smokebox door up until their withdrawal. Others carried the larger diameter and more rounded Darlington LNER smokebox door, after reboilering, though at least one - 69791 photo below - had the later superheated 63B boiler, extended smokebox but with original chimney and smokebox door; it also had it rear footsteps, under the rear of the bunker, removed and had the half height sandboxes - photos of the prototype at the time modelled, nuff sed.

 

So now to add the handrail stanchions, safety valves and whistle and then solder the whole boiler assembly into the tanks and onto the footplate.

 

Cheers

 

Mike

[ArthurK]

We slipped up with chimney on this one. The one I originally supplied to Mike was too short. (We believe it was that for the A7). The only alternative to hand was that from the Q5 which is a smidgen under the desired height and without the Capuchon. A replacement master is in hand and the correct chimney will be available when this kit is ready. I am slowly building up a goodly supply of the standard NER parts (chimneys, domes, safety valves, smokebox doors etc.) and also those for the tenders including old and new toolboxes. All will available separately. Get in touch if you wnat any of these.

 

ArthurK

[mikemeg]

We slipped up with chimney on this one. The one I originally supplied to Mike was too short. (We believe it was that for the A7). The only alternative to hand was that from the Q5 which is a smidgen under the desired height and without the Capuchon. A replacement master is in hand and the correct chimney will be available when this kit is ready. I am slowly building up a goodly supply of the standard NER parts (chimneys, domes, safety valves, smokebox doors etc.) and also those for the tenders including old and new toolboxes. All will available separately. Get in touch if you wnat any of these.

 

ArthurK

 

Chimneys are notoriously difficult things to get just right, yet they characterise not just a locomotive but the look of the railway company responsible for their design. Even after the surgery on this Q5 chimney I am still querying whether I have actually got this quite right and, I think, the barrel of the chimney is a fraction of a millimetre (.25 - .5) too slender, though I think the height, the taper and the top is about right. It is the photo of 69791, above, which I used as the datum for this chimney; the reader can, perhaps, judge whether the chimneys match, given the differences in viewing angles.

 

I applied a coat of primer to the chimney prior to fitting it, just to ensure that none of the joints, which I added to it, were visible. I think a fairly thick coat of black, liberally applied to this chimney, followed by another coat of primer when the whole body is primed, should about do it.

 

Having now used many of Arthur's castings I can testify to their accuracy and quality, especially the most recent brass ones which are superb and fully inkeeping with the quality of the brass and nickel silver etches. Arthur now includes, within each and every kit, an etch of 'bits and pieces' i.e. various brass washers of different sizes, handwheels and boiler bands. This etch is well worth the price as an individual item; the boiler bands especially are spot on.

 

Cheers

 

Mike