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Mikemeg's Workbench - Building locos of the North Eastern & LNER

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BUILDING THE HIGH LEVEL MODELS J72 CHASSIS KIT

 

Quite a few years ago I did a Bachmann J72 conversion, to P4, using a MainlyTrains Chassis kit for the J72. This loco has run well with its High Level 108 : 1 gearbox and a Mashima 1020, so why do the chassis again? While talking to Chris Gibbons, of High Level, regarding an order placed on them, I was persuaded to have a go at their chassis kit for the J72, which is far more prototypically accurate for the J72.

 

When the first twenty J72's were built, by the North Eastern, they used a fairly simple brake linkage arrangement with two pull rods, one either side of the loco to operate the brakes, as per the Mainly Trains chassis kit. Later batches of J72's built both by the LNER and by British Railways, employed a compensated brake linkage arrangement with a single, centrally located compensated pull rod.

 

High Level's chassis kit therefore suits all J72's except the first twenty, which also had a shorter bunker (5 3/4" shorter) than the later LNER and BR batches. Chris also took the opportunity to model the cylinder and valve fronts, the motion plate and the internal motion of these locos in much more detail. The kit is designed to support compensation of the middle and rear axles, with a single rocking beam on the front axle, though it can also be built usng CSB's.

 

The nickel silver etched sheet contains no less than ninety parts, though some (frame spacers, frame spacer overlays, brake yokes) are alternatives for OO, EM and P4. This sheet is etched in a very fine gauge nickel silver (.012") so care must be taken in cutting out the parts and in their handling once cut out, to avoid any distortion. The kit also contains a modified High Level Humpshunter gearbox and a set of 108 : 1 gears designed to accommodate the Mashima 1020 motor.

 

The instructions, provided with the kit, are very detailed with a number of drawings showing the sequence of assembly and how the various parts relate to each other, especially on the internal motion and on the brake gear.

 

Anyway, after a couple of days the basic chassis is assembled, using the chassis jig, with the cylinder and valve fronts all assembled and with the initial components of the internal motion (one crosshead) also fitted. Many of the parts on this kit are three layer etches - the coupling rods, the driving wheel springs, etc. so care must be exercised when soldering up these parts.

 

So this is the state of play after that couple of days and before I launch into the internal motion and the brake gear. Some of the detail is very small so does not show up easily on the photograph but the representation of the cylinder and valve glands and the drain cock mechanism (hidden from view on this photo) is a joy to behold!!

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

The slide bars and cross heads have now been assembled and fitted between the cylinder fronts and the motion plate, with the crossheads in different positions along their relative slidebars. The piston rods (0.9 mm wire) have also been cut and fitted.

 

At this level of magnification then every scratch, every bit of dirt shows up to 'real advantage'. Cruel, these close ups.

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

Which axle are you driving off?

 

Dave.

 

The kit is designed to be driven off the rear axle. The position of the motor support frame spacer (the one with the curved top in the first potograph) really dictates where the motor should go and its orientation.

 

Cheers

 

MIke

Edited by mikemeg

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Mmmmmm.

I find this most useful as one of these kits is to be aquired, when funds allow that is.

Cock on Mike.

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Just be aware that there is a numbering snafu on a couple. Of the cross heads.... Should go and dig out the instructions where I wrote this all down!

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

Mmmmmm.
I find this most useful as one of these kits is to be aquired, when funds allow that is.
Cock on Mike.

 

Ian,

 

Thanks for the comments. Looking at this set of etches, initially, is a little daunting but Chris's instructions do contain some very useful tips for its building :-

 

Only cut out only those parts to be assembled next. Many of the parts are so small that they can very easily be lost if they are left lying around the work area.

 

A lot of the soldering of the multi layer parts relies on their being lined up on the very small holes at the ends. Chris advises using wire, dipped in oil, to locate these parts while soldering; the wire being then withdrawn. I also use some very small broaches, both to open up these tiny holes and, dipped in oil, as locators while soldering them up.

 

Like anything, this depends on a little patience, a little attention to accuracy and using a very small amount of solder on the tip of the iron. I've also found that because of the concentration needed both to locate the appropriate parts and to then solder them up and assemble them, I have to do this in much shorter sessions than I would normally. Just a function of age, perhaps.

 

That said, I did assure Chris (of High Level) that I would build this as per the instructions (with Arthur's test builds I don't normally have instructions so tend to make it up as I go along) and that I would leave nothing of the kit off the build. So far, that has been done!!

 

Still a very enjoyable build and once I can photograph it from far enough away to 'disguise' all the bits of muck and tiny scratches, then it should look the part!!!

 

Cheers

 

Mike

Edited by mikemeg

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

A couple of folks have pm'd me to ask a few questions about building this, so I'll try and answer those questions via this thread. I'll try and illustrate the next stages, step by step.

 

The front cylinder plate and the motion plate both contain the holes for the valve spindles. Many North Eastern inside cylinder locos, used valve spindle guides which were attached to the motion plate. The instructions recommend that these valve guides are made using 3.5 mm pieces of 1/16th outside diameter tube, located side by side in front of the motion plate. I found that to allow these two pieces to lie side by side and allow the correct spacing of the valve spindles, a small flat needed to be filed on each of the pieces of tube. I normally do this by pushing the small piece of tube onto a broach until it is tight and then filing the piece on the broach; effectively using the broach as a mandrill.

 

So after filing up the pieces of tube for the valve spindle guides, then two pieces of 0.8 mm brass rod were cut for the valve spindles, ensuring that they would not foul the path of the front chassis/body fixing. These were then partially pushed through the valve spindle holes and a piece of the tube slotted onto each spindle. When both tubes were located on their spindles, the spindles were finally pushed into the locating holes in the motion plate and the tubes then butted up to the motion plate. The valve spindles were then soldered to the inside of the front cylinder plate.

 

The oil hatch is then located on top of the valve spindle guides, pushed into its slot in the motion plate and then glued into place - this is too small to solder. Finally a tiny piece of 0.2 mm wire was cut and glued to the top of the oil hatch to simulate the oil hatch hinge.

 

Another of those 'cruel' close ups to show the arrangement. This photo also shows the tiny brackets which reinforce the fixing of the rear of the slidebars to the motion plate. Again, these are very tiny and need to be very carefully soldered to the underside of the slidebars.

 

Whilst this is probably the most detailed and intricate kit I have ever built, it is all perfectly doable; with care; quite a lot of care!!

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

The central valve gear locator has now been assembled and soldered to the motion plate, after which each of the two drop links have been soldered up and then threaded onto a 0.7 mm shaft which locates into the valve gear locator. The ends of the shaft have then been dresssed off on the outsides of the mainframes.

 

Only a very short section of the eccentric rods, from the drop links to the eccentrics on the driving axle, is modelled as these disappear behind the side tanks and are therefore invisible.

 

Now only the weighshaft and lifting links to add and the inside motion is then complete.

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

The weighshaft assembly is next bent up with the strengthening layers soldered to the lifting rods. A 1.0 mm piece of brass rod is then cut slightly oversize to fit across the mainframes and then slotted into the appropriate hole in one mainframe. One weighshaft journal, plus the lifting rod assembly plus the other weighshaft journal are then threaded onto the weighshaft, which is then slotted into the appropriate hole in the other mainframe.

 

Once everything is centred and located the weighshaft and its journals can be soldered into place and the lifting rod assembly positioned at the appropriate angle.

 

And that's it for the inside motion!!!!

 

The photo, below, probably doesn't do justice to the quality of the etching of these tiny parts but I think this does look the part. I'll charge up the batteries for the digital camera and try and take a sharper photograph!

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

So, before the brake gear is assembled and fitted, the acid test; does the chassis ride level and at the correct height. To ascertain this I need to fit the three sets of driving wheels and then take them off again, prior to priming and painting the chassis. Still, this is a good check on the running of the axleboxes as these are often just a little tight on the axles. And, they are just a little bit tight so a very light run round with the broach just to allow the axles to revolve more freely.

 

The holes at the top of the front of the mainframes and those on the tiny mainframe upstands at the rear of the frames are to take the sand pipes.

 

Cheers

 

Mike

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Edited by mikemeg
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HIGH LEVEL MODELS J72 CHASSIS KIT

 

So, the final activity for today is folding up the body of the gearbox, fitting the axle bearings to the gearbox and then checking that the steel gear shafts will pass through the two sides of the box without problem, thus ensuring that the gearbox sideframes have been folded up parallel and square. These shafts for gear stages one and two still have to be cut to length, which is why the gearbox is not yet sitting at the correct orientation.

 

The outsides of the top hat bearings forming the gearbox axle bearings, did need filing back a little so that they were a reasonably slack fit between the mainframe axleboxes, allowing the whole gearbox assembly to rock from side to side with the movement of the compensating beams.

 

Cheers

 

Mike

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Edited by mikemeg
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Hi Mike

 

I wish you had started this build a few weeks ago, it would have been a great help to me.

 

I'm just coming towards the end of my first ever chassis build, a High Level kit for the Deans Goods which I've documented here http://www.rmweb.co.uk/community/index.php?/topic/98645-dean-goods-high-level-chassis/page-3&do=findComment&comment=1952515  Mine is in 00 and built rigid mainly because I was worried about making a mess of it which thankfully hasn't happened. I've found the instructions to be very good and it has virtually fallen together. Being my first build I've had to research and learn a few tricks along the way but I'm very impressed with the design and detail of these kits.

Edited by nickwood

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..... this is probably the most detailed and intricate kit I have ever built, it is all perfectly doable; with care; quite a lot of care!!

 

You've not met Dave Bradwell's J27 kit, then?

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Your right Horse... I keep looking at all the bits for the chassis and go "How can I get this to look good?" and "all the bits are there how do I put it together with out stuffing the running as I don't what the gear to work?" My current version is on the scalefour list at the moment.. though time has escaped again as I am working again! 

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

 

You've not met Dave Bradwell's J27 kit, then?

 

Horse,

 

No, I haven't encountered Dave Bradwell's J27 kit but I have encountered Dave Bradwell's B1 chassis kit and, now that you remind me, that probably holds the record, for me, for complexity. However, I do think that anyone's perception of complexity is largely incrementally influenced by what they have done already, so having now pretty well done this J72 chassis, I would, perhaps, look differently at Dave Bradwell's kits. Mind you even from this new perspective, they'll still look bl--dy difficult but achieveable.

 

Anyway, I sat the J72 body on the part completed chassis and checked the ride height against the test build of Arthur Kimber's J71. Mistake; massive mistake. The J72 model simply isn't in the same parish as that J71, even with the much more detailed chassis. So the plastic footsteps on the J72 have come off and will be replaced by some scratch built ones. The cab, which is devoid of everything inside, will now be modelled with a cab floor, backhead and the appropriate detail, including a crew, proudly staring out of the cab cut out of their newly updated charge.

 

So a simple change of chassis has now become a fairly substantial rebuild.

 

I really should know better than to upgrade one aspect of a model for, inevitably, the rest of the model then looks distinctly inferior. Tell you what, though, the two together do look nice, and when I add a J73 and three J77's then I'm getting close to that Saturday lunchtime 'crocodile' of shunting locomotives going through Hull, on their way from Victoria Dock to Hull Dairycoates shed, for boiler washout. Happy days, long lost in the mists of time!!

 

Cheers

 

Mike

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Edited by mikemeg
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 Dosen't this show how good the origional model was for its time??

    More power to you for upgrading old gear. This is what we did before the glut of superdetailed models we have today. Not that I am knocking todays models by any way!!

     You will have your own unique loco which is, I think, the reason why a lot of us do this hobby.

                   Best Wishes.

                                 Chris.

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 HIGH LEVEL MODELS J72 CHASSIS KIT

 

 

 Dosen't this show how good the origional model was for its time??

    More power to you for upgrading old gear. This is what we did before the glut of superdetailed models we have today. Not that I am knocking todays models by any way!!

     You will have your own unique loco which is, I think, the reason why a lot of us do this hobby.

                   Best Wishes.

                                 Chris.

 

Chris,

 

Many thanks for that. Yes, the Bachmann J72 isn't a bad model and is dimensionally pretty well spot on. It is still the best model of a J72 available and, with a little work - filling in the underside of the boiler; adding tank breathers where applicable, adding cab floor and details, etc - can be made into a very good model.

 

So I will upgrade this model to the standard of the chassis and to something approximating to the quality of the J71. And, looking through the box of 'miscellaneous items' I've come across another J72 body in almost perfect condition. And as I have the motor, gearbox and wheels off the old Mainly Trains chassis all in working order, then one might become two.

 

Easy to see, now, why I have so many of these North Eastern 0-6-0 tanks.

 

Cheers

 

Mike

Edited by mikemeg

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

Couldn't resist this one. If the blue paper background had been larger, then more 0-6-0 tanks would have been added. They are, from right to left, J72 (longer bunker version and BR 1949 -1951 batch), J71, J73 and J77 with the Worsdell cab.

 

Surely the J72 must hold some kind of record for continuity of building; 1898 - 1951 largely unaltered!!

 

I wonder if anyone will do a kit for the shorter bunker version of the J72, representing the original North Eastern built batch of twenty?

 

Cheers

 

Mike

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Edited by mikemeg
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Here's the list of jobs I did to my recent build, an early short bunker one. 

 

http://www.rmweb.co.uk/community/index.php?/topic/3252-worsdell-forevers-workbench-loads-of-north-eastern-stuff/?p=1731463

 

Many years ago I built a Bradwell 20t* hopper underframe, yes, very complex but very good to build.

 

Short bunker J72? Perhaps!!!

 

ArthurK

 

No Arthur! I've just finished mine  :nono:

 

 

*BR decided to uprate them much later, this was pure LNER.

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

The last sub-assembly to build is the compensated brake pull rod. The kit provides three sets of etches for the brake yokes (OO, EM and P4) located on what is, effectively, a jig for assembly of the brake pull rod. By removing those parts not needed for the gauge to which this is to be built, the remaining parts are automatically spaced at the correct spacings for the brake positions; the photo hopefully shows this.

 

Location of the various layers, for soldering is by use of a piece of oiled wire, which is withdrawn once the soldering operation has been done. I also use a very fine broach for positioning, again just dipping the broach in oil before soldering. Small pieces of 0.3 mm wire were then soldered into the various holes in the compensating linkage and the filed back to protrude by around .010"; this to simlate the bolts on the pull rod.

 

So this is now ready to be cut out of the jig and fitted to the brakes and to the adjusting mechanism at the rear of the chassis.

 

Cheers

 

Mike

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

So with the brake arrangement from the cab to the cross shaft done, a quick sit of the body on the new chassis. Now only the brake pull rod to fit and the final adjustment of the brake positions and then 69003 is ready for some running trials prior to adding the final details to the body - new footplate steps, cab floor, backhead, brake standard and crew.

 

The BR rear sandboxes were made for the original chassis so these will be added to this chassis with the sandpipes.

 

Then the loco will be weathered a little to reflect its condition in mid 1950.

 

After that, I'll do it all again on another Bachmann J72 body as one of the later batches 68690 - 68754.

 

Cheers

 

Mike

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HIGH LEVEL MODELS J72 CHASSIS KIT

 

The initial running trials were very encouraging with only the hint of a tight spot. One of the problems with these locomotives, indeed many of the smaller North Eastern locomotives, is that the coupling rod journals were very small, often around 8" (2.66 mm) diameter. If Alan Gibson wheels are used, with their crankpin colletts around 1.6 mm diameter, then there is only around .5 mm (.020") of journal left, around the collett, when they are drilled out to take the crankpin colletts. And this assumes absolutely perfect symmetry between the wheel spacing on the mainframes and the coupling rod spacing, so that no enlargement of the holes in the journals is necessary to cater for slight differences in spacing.

 

I confess that I did turn the crankpin colletts down a little - perhaps to around 1.4 mm diameter - to try and retain a little more metal on the coupling rod journals; though these rods are three layer etches, so there is plenty of depth to the journals.

 

So now to the additional detailing of the body.

 

All in all this High Level chassis kit is very well designed and does go together very well, though care must be taken with the smaller parts. It certainly produces a much more prototypically accurate chassis for the J72 than earlier chassis kits for this loco.

 

So as I have another Bachmann J72 body plus the wheels, motor and gearbox then I'll do another one.

 

And where was 69003 based, in mid 1950? Hull.

 

Cheers

 

Mike

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Edited by mikemeg
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