Leek & Manifold Kitson 2-6-4T

[tedp]

Those of you who also are on the NGRM forum may have seen this before, but I decided to copy it to the 009 Society forum and try to catch up with what I wrote elsewhere.

At the moment I am building a L&M Kitson, using the Meridian (ex Centre Models) body kit and a Backwoods L&B chassis. Both were obtained at Expong about 10 years ago and they are still staring me in the face.

Why not a Minitrix chassis which the Meridian kit was adapted to? Obviously the inside frames put me off for this rather huge narrow gauge loco with its low-slung look and big balance weights whirling round outside the frames. I would have had to do a false frame job on it but I wondered if building a straight outside frame chassis wasn't an easier approach, more so as I would have to re-motor the Minitrix chassis into the bargain.

The Backwoods L&B 2-6-2 was chosen as the wheel diameter and axle spacing are very similar to the Manifold loco and the height of the frames is close enough. Obviously the rear of the frames will have to be modified to accommodate the bogie, and there are other issues like the peculiar cranks/balance weights and the Walschaerts valve gear as the L&B chassis includes an etch for a Joy motion. The crank issue is being solved already by the kind cooperation of another modeller.

It is over 10 years since I built my C&M 'Atlantic' from a Backwoods kit so I will have to re-learn brass kit soldering, at least for the chassis.

Just to compare, I superimposed the frames of the Backwoods L&B chassis over the 4mm scale drawing in the April 1996 Railway Modeller. You will notice I laid a steel ruler next to the scale on the drawing just to check on the dimensions.

I appear to have bitten off quite a big chunk here as the frames will need considerable modification. Serves me right...



You will see that the frame height is all right, but apart from it having to be cut away and extended, the shape of the frames at the front and rear end is wrong. The Kitson style frames would have to be altered anyway as the swing of the front truck and the bogie will need considerable more space than allowed by the Kitson frames. The wheelbase is about 1mm too long, which doesn't bother me - 25mm instead of 24mm.

Using the Backwoods chassis seems to be a good idea as most of the precision work has already been done in the etch. In addition the kit includes a motor, gears, wheels, bushes and all kinds of odds and ends that will help me build a working loco.

It seems there is an etch being produced by Robert Thompson for L&M valve gear which will replace the Joy gear of the Backwoods chassis.

[tedp]

1. Fitting the bearings to the frames

Yesterday I fitted the bearings into the Backwoods L&B frames, experiencing some problems. The bearings are brass bushes with a flange on the end. They go in from the inside of the frame, where the half etched rivet holes can be seen. I supported the complete etch and put in the bearings, having to slightly ream one or two holes in the frame plates. Then I applied a little flux to each bearing, rotating them slightly so the flux would be spread. A tiny sliver of solder next to each bearing was enough - heat the bearing and it will flow in.

The main challenge is to grind down the protruding part of the bearing bush flush with the frame. Pete Mc Parlin in his construction guide says to grind it down with a sanding or grinding disk in a minidrill. A file leaves marks on the frames. Well, I tried grinding it down one bearing and succeeded in overshooting so I went a fraction into the frame. It's not too bad but I decided to go easier with the other bearings. I finished one with a file and indeed left marks. So back to the grindstone again and go very easy. I finished all using fine wet-and-dry emery paper. The damage done is not too bad - it will be hidden anyway.

The bearings fitted into the frame, with one ground down slightly too deep:



The reverse side, showing the flanges where they are soldered to the frames. The excess solder on the faces has been removed using a file and emery paper.



The outside faces of the frames with the bearings trimmed flush. Note a few file marks and the lower left bearing ground slightly too deep. Otherwise all is well.



To conclude, I think having to grind or file down the bearings flush with the frames isn't a happy solution. I would prefer bearings being better sized.

To be continued!

[tedp]

2 - assembling the frames, first stage

I first embossed the rivets on the frame. These are in a different place from those on the Kitson, but who cares. On a Backwoods kit that is done by giving one or more soft taps against a sharp tool put into the half etched holes in the back of each frame. The frames will curl a little, but they can be bent into shape again. Use a piece of soft wood under the etch, in this case the workbench edge.



The second photo shows the frame assembly released from the etch using a sharp knife. The embossed rivets show up clearly.
 


Next the frames are folded along the half etch lines of the rear end bridge. Note that I haven't yet done a thing about cutting away the pieces of frame that have to go. I'll tackle that later. Possibly a wrong choice, but I'm feeling my way along as much as anyone else would have done.



Now the wheelsets are assembled, with a 25 tooth gear on the rear axle. This is a push fit, as are the insulated wheels. The 7.4mm back to back gauge I made up some time ago is a great help. I'm not going to 7.5mm as some of the old Peco points I have don't like that. The wheelsets are inserted in the frame with an insulating washer adding a slight space to prevent the insulated wheels touching the frame on their side. Naturally all wheelsets were put in with the insulated wheel to the same side.





Now the motor mount is taken out of the etch and folded. On the L&B chassis this includes brake cylinder supports and the cab steps. The cab steps were cut off as they aren't needed. I only left their stretchers on, but probably these will have to go as well. Note the solder blotches, these can be filed off later. No need for clean soldering here as this goes under the footplate anyway.



Finally, the front bridge is added to the frames, and the bridge piece under the frames below the motor mount. When I will cut away the rear frames I will start from the lower bridge piece which can be seen in the second photo below.

Note that at the front some more stiffening is needed. The Backwoods chassis has a fold-up cylinder block assembly which fits in a slot in the frames just behind the front bridge. I will solder a piece of the edge of the N/S etch into this to improve the rigidity of the chassis.





The chassis now runs smoothly through all trackwork, although I notice one wheel - again - isn't quite true. It does run rather better though than Atlantic's chassis which is made up with the old style wheels.

To be continued!

[tedp]

3 - fitting the footplate

I had to remove some whitemetal from the footplate to make it a snug fit on the chassis. The material to be removed is indicated below:



I used a variety of ways to remove the whitemetal bogie mount, a piece around the front mounting hole which I won't use, and a few cast-on strips at the back of the footplate. Grinding away with a grindstone disc in a minidrill is a heartbreaking process as the whitemetal starts to smear and even clogs up the grindstone. In the end it is reduced but the finishing needs to be done with a file and a sharp knife. The bogie mount is intended to take a screw running in a slit in the bogie, but any sliding connection to a bogie is an unhappy solution - I prefer a swing link. So I fitted a hacksaw in the vice and ran the circular mounting boss against it, using my nails to keep the footplate itself away from the saw blade:



After having cut into the whitemetal boss from both sides, I gripped it with pliers to break it off:



Next, using a scalpel and a file, I cleaned up the remaining pieces until the underside of the footplate was flat. The scalpel can be used to shave away the whitemetal. Keep your fingers away from the business end as this strains the scalpel blade which may break or suddenly end up in your finger. In the lower photo, note the tiny notches that clear the tiny tabs on top of the frames where the Backwoods motion bracket was supposed to go in. These provide convenient locating aids.





Here is the footplate resting on the chassis, the back end of which will have to be cut away to clear the bogie:



Note the footplate may need further cutting away to clear the motor. This would help losing some weight at the rear end.





With this final photo showing the chassis fitting flat against the footplate I will end this post.

This morning when I tailored the whitemetal footplate to the chassis and sat it on the track, I found that all insulated wheels to some degree aren't running true. The tail heavy footplate probably pressed down on the rear wheels, and it yaws like a flat bottom barge sailing before the wind. So even the insulated Jackson wheels in this kit are no good. I wonder how to proceed. Order new ones hoping they are better? The uninsulated ones seem to be good. I can easily take apart the chassis again as nothing has been fitted but the motor mount and a few bridge pieces.

Perhaps if I quarter the cranks so all wheels are 'in phase', only a slight movement will remain.

To be continued!

[Krizzy]

Brilliant work Ted, you have given me the urge to get on with my half complete Backwoods 'Russell'. I'm at the dangly bits stage that has stopped me. Although I have built three other similar kits I still need to build up my own confidence to tackle the motion and fit on to the model.

Roger

[tedp]

Thanks Roger - the motion is a tricky thing indeed. Even once the quartering is done you have the tiny bits to solder together without locking them up. Paper barriers etc.

But for the moment I'm stuck with the wheels. What are your experiences with the Jackson wheels? Rod Allcock advises to order Jackson disc wheels but I wonder if these are any better. Perhaps the answer is to quarter them all 'in phase' so the bunker end doesn't pitch up and down and only a slight rolling motion remains.

[rod335]

Ted

Regardless of what route you go down, off-centre wheels will always be off-centre wheels and in years to come you will regret it if the loco does not run evenly, not the same thing as smoothly. In my experience, off-centre wheels are caused by either the insulating bushes going out of true when fitting the wheels to the axles, or by the effect of heat on the bushes when soldering on the flycranks. The insulating bushes on the Jackson wagon wheels seem to be made of a firmer substance than those on the spoked wheels, and using the methods I have explained to you I have never had a problem since. But it's up to you.

Rod

[tedp]

If the bushes on the solid wheels are more robust perhaps that's the way to go. I can have a try at ordering a set of six wheels and see how they turn out. I just had a close look at the wheels in the chassis and they are absolutely no good, being about as bad as the ones previously supplied by Backwoods. They may have been a bad lot, I don't know, but as it's 10 years ago since I got them it cannot be traced anymore.

[Krizzy]

The last few posts prompted me to look at my Backwoods locos trying to remember how I put them together. It is now seventeen years since I built the first loco of my two versions of the Vale of Rheidol 2-6-2Ts. I had problems with the plastic spokes when fitting the valve gear like others have had. I dismantled the chassis and replaced the wheels with Alan Gibson solid disc wheels on the advice of Pete. Disc wheelsets were fitted when buiding the second VOR loco from the outset. I then moved on to a 'Canopus' kit that has spoked wheels and smaller diameter brass axles. This time I made sure I flooded the chassis with plenty of water when soldering the cranks to the axles. It worked and so does the model. When I came to build my L&B loco 'LEW' the same method was employed and I am pleased to say that too runs well so far. As mentioned in my previous post I am now at that stage of putting the motion together and then to attach them to the 'Russell' chassis. The cranks are already fitted with just a little tightness in one part of the wheel rotation. The VOR locos were the same but the tightness disappeared as they got run-in so I am hoping the same will apply with my 'Russell'.

Roger

[tedp]

Thanks Roger - the problem isn't soldered cranks distorting the wheel centres (I haven't yet fitted cranks), but the plastic insulation muffs in the wheels that are out of true. The all metal wheels run almost perfect, but there is about 1/10 mm of wobble on the insulated ones (all of them in fact) which is greatly exaggerated on the end of the chassis when I run it over the track.

The Alan Gibson wheels have black plastic centres and these are out of true on 'Atlantic', again not due to soldering the cranks as I water cooled them carefully. With the new nickel silver wheels I had hopes the problem would be over but it's still there.

Meanwhile I found out the Jackson wheels Rod advises seem to be the same as 4mm scale Romford wagon wheels on 2mm axles. These are in the Markits catalogue.

A little tightness in these chassis at the start isn't unusual. I flooded the bearings and the crankpins of Atlantic with polishing paste and ran the chassis with the wheels in the air until the tightness had worn away.

[WALLSHIRTS]

You can also use space age epoxy and glue the cranks on...
Mal.

[tedp]

I was thinking of Loctite. But I will have to wait for wheels and cranks first - I'm afraid there is a slight delay to the project!   ::)

[tedp]

4 - modifying the frames

Having removed the offending wheels and ordered new ones, I decided to use the interval to have a go at modifying the rear end of the frames from a Lynton & Barnstaple Manning Wardle pattern to the much longer Kitson 2-6-4 frames. The difference is indicated in blue on the image below, superimposed on the Railway Modeller diagram.



As the frames over the rear bogie are quite shallow, I decided to use a piece of 1.5mm square brass pipe both as frame extenders and as a cutting guide (the green shape on the diagram). I cut two pieces of pipe to length and soldered them inside the frames with 11mm protruding. The soldering was done using 145 degree solder as opposed to the 188 degree stuff used for the frames.

The reasoning behind this was that if the frames have to be unsoldered to fit new wheels, I can try and remove the extensions, just in case I need to bend the frames more than allowed by the brass pipes, without disturbing more than I want to.



On the outside of the frame I lightly scribed the approximate contour of the curve to cut away behind the wheels. You may have noticed that beforehand I also cut away the unnecessary extensions to the motor mount protruding outside the frames. This allowed me to clamp the unit in a vice for the cutting operation.



Then I carefully cut the frames, using the brass pipe as a saw guide:







Next, I ground away the diagonal angle to a nice curve, which isn't exactly the shape of the prototype, but near enough to satisfy me. The pieces of frame cut off then were measured against the protruding pipes and shortened:



And finally these were soldered against the square pipe, resulting in a neatly spliced frame. Again, the shape isn't exactly that of the prototype, but it should be good enough.







The forward end of the frames needs a part cut out, following the half etched pattern in the frame and a bit more, but I will delay that until the chassis has been fitted with wheels and can be braced up front.

To be continued!

[tedp]

I realise I have been remiss in following up this thread on the Society forum. Since I lacked some parts to continue work on the chassis, I decided to have a go at the whitemetal body. I have taken heed of the dire warnings about weight at the bunker end of the loco, and I decided to check on the balance of the whitemetal body before assembling it altogether. And indeed, there is considerable weight aft that will either have to be eliminated or balanced.



I removed some excess metal from the rear of the footplate. I cut a rectangle out of the whitemetal right in the spot where the motor wil be. This would have cleared the whitemetal, but anyway it removes some weight.

Then I put together the boiler, smokebox and the tanks and cab sides. The boiler has an upper and a lower part and is integral with the tank tops and bottom. They were glued together with neoprene glue right where the wide gap can be seen in front of the tanks. The neoprene would keep them together during the fitting process of the tank sides and smokebox. These had to be filed to size slightly, but all went together with a minimum of trouble. The tank/cab sides were glued in with cyanoacrylate gel. They slightly force the boiler/tanks top and bottom apart but that was what I needed the neoprene glue for as it stays a little flexible.

The smokebox saddle had to be thinned down a little so it would fit between the frame ridges on top of the footplate. Then it could be glued on with cyano gel, flattening out the assembly on the workbench top.

The cab doors are thick whitemetal and these may have to be cut out and replaced by a piece of brass or nickel silver sheet for strength. The cab front is a loose fit - it may have to be replaced by styrene. The bunker, the cab roof and cab rear will all be replaced by lighter material, probably styrene. There will be a lot of weight added at the front end - smokebox front, dome, chimney, cylinders, headlight, sandboxes etc.

The body will fit over the motor mount. In view of the weight needed to balance the rear end, I am considering fitting a Mashima 12/20 can motor instead of the 10/15 supplied.

Shape of things to come:



The loco body set up on the frame, blocked up on the track at Rae Bridge. Note I used the whitemetal roof and cab front which will be discarded. Smokebox front, chimney and dome only slotted in place.

[tedp]

It will be a huge loco, but very similar to the size of many of my other locomotives. The kit includes numerous detail parts not yet shown. You will have seen the fit of the tank sides isn't very good, but most of this will be camouflaged by detail parts, or by filling the gaps.

A balancing act. Warning: calculations ahead!

The Kitson model, as indicated above, is very tail heavy. I wondered how much or how many of the whitemetal castings to remove or discard so I could still keep the loco in some sort of balance.

Normally when a loco is on its wheels, I balance it using letter scales, resting the front wheels on the scales and the rear wheels on a pile of books. In this case the wheels are still on order, so I had to resort to a different method. I passed two 2mm drill bits through the bearings and supported this on two paint tins at one end, and a plastic casting under the drill bit at the other end.









Usually I don't do a detailed analysis but I simply add weight until the balance evens out a little. In this case I don't want too much weight. So I did a few tests and some calculations, and I came upon the following.

The entire Kitson model at this stage weighs 120g, which excludes a lot of detail castings. To compare, the completed model of Atlantic weighs 150g. Using the letter scales I determined that of the 120g, 35 is on the forward wheels and 85 on the rear wheels, a difference of 50g. If we assume the centre wheels are the pivot point, and the distance to each of the outer axles is 1.3cms, the leverage exerted is 85-35=50g*1.3cms, which is equals +65g*cms (+65 for short).

- Adding the motor adds 10g at a 3cm distance to the rear: leverage +30.
- Adding chimney, dome, cylinders etc adds 20g to the front at a mean distance of 2cms : leverage -40.
- Adding 20g of lead in the smokebox, between the frames and in the front end of the tanks will add a leverage of -32.

Removing the whitemetal bunker sides/cab doors would remove 8 g from the rear at a 5.5cms and result in a leverage of -40 g*cms. This is most effective but I don't want to remove these as it will mean I have to rebuild the entire cab/bunker assembly. So I will be adding lead to the front. The end result will be a leverage of 65+30-40-32g*cms = +23g*cms.

The entire model with motor, detail and ballast, but excluding wheels, will weigh about 120+10+20+20=170g, with about 23/1.3 = 17g (10%) bias towards the rear wheels.

All this is theory, but I now know enough to leave the cab and bunker sides intact. ;)

In order to fit the footplate, which is the base of the entire body, to the chassis, I carefully soldered two nuts to very thin brass shim and managed keep the thread free from solder. Inserting a screw proved to be enough to clear the thread in the nut. So I cut out the squares of shim and superglued them to the footplate, after flooding the inside of the nut with a drop of oil to prevent the screw sticking. I filed a tiny recess in the bottom of the smokebox saddle, and it seems that all fits...