Building the 'Chocolate Zephyr' (GT3)

[cctransuk]

Photos copyright T. Shackleton

 

 

As long-promised, I am about to embark upon my GT3 build. In the absence of surviving works drawings, it seems unlikely that even Heljan will take this one on, and I have always been determined to have a model of this iconic locomotive.

 

GT3 was, by all accounts, very successful, but the prevailing rush to eliminate all traces of steam-age power from BR mitigated against it, and the sudden surge in the price of oil dealt the death-blow to the project.

 

I understand that the purpose of the GT3 project was to demonstrate that steam locomotives could be updated to a more environmentally and operationally acceptable form of motive power, without scrapping the entire machine.

 

Given the incredibly short operational life of the BR Standard locomotives, (had the price of oil remained low), a more rational modernisation policy could perhaps have seen GT3-type rebuilds operating for some years, as the intermediate stage on the way to widespread electrification.

 

Be that as it may, I accumulated the various kits and components over several years :-

 

 

The Golden Arrow resin kit http://www.goldenarrow.me.uk/products.htm#other

 

The etched detailing kit from macgeordie of this parish http://www.rmweb.co.uk/forum/viewtopic.php?f=8&t=46203

 

 

The High Level chassis kit http://www.highlevelkits.co.uk/

 

Assorted additional components (mostly Markits) http://www.markits.com/

 

A collection of mystery components which may, or may not, find a home in GT3 !

 

A pair of miniature low revving gearbox motors that MAY drive the loco air intake fan and the tender scavenger fan.

 

A greyscale image of part of my transfer sheet BL149, (which was used on Tim Shackleton's model, see photos above) http://www.cctrans.org.uk/products.htm

 

So, with the combined skills of all of the above producers, there should be no excuse for not producing a first class model - we'll see !!!

 

Next episode when I get to work.

 

Regards,

John Isherwood.

Edited September 15, 2016 by cctransuk

[MJI]

Looks interesting

 

I do like the live gas turbine one I have seen on You tube

[cctransuk]

Saturday afternoon, indifferent weather - time to make a start; (at long last)!

 

The first job involved none of the above components. I bought a Poppy's eight-coupled chassis jig after several list members of repute extolled it's virtues.

 

Assembly was a breeze, involving nothing other than white wood glue and elastic bands.

 

 

Assembly of the coupling rods was next on the list. The instructions recommend the use of 1.0mm. drills to align the three laminations, but the crankpin holes were etched nearer to 1.25mm. diameter.

 

So, having established that the crankpin bushes that I intend to use are 1.5mm. diameter, I used 1.3mm. drills as the alignment pegs. These were drilled down into the soldering board to form a jig. The crankpin holes in the three laminations were opened up a mere touch, until they would just slide onto the 1.3mm. drills.

 

 

The laminations were then pressed together with a wooden cocktail stick; 15% phosphoric acid flux was applied round the edge of the laminations; and then solder was applied with a good, hot, medium-sized soldering iron bit. The solder flashed around the edge of the rods in a most satisfactory manner, and when cooler, the rods were removed from the drills.

 

A little cleaning up with miniature files and a fibreglass stick followed, and then it was time to join the two parts of the articulated coupling rods. I had some nickel-silver valvegear rivets which have a bearing diameter of 1.1mm. and a shank diameter of 1.0mm. The joint holes in the rods were carefully opened out to be a easy fit on the bearing diameter; (the front lamination); and a tight press-fit on the shank diameter; (the rear two laminations)

 

Having assembled the two parts with the merest touch of oil on the bearing surface of the joint rivet, a touch of flux was applied to the back of the rod where the end of the rivet was visible and, holding my breath, a touch of solder was applied. Contrary to expectations, the solder took to the back of the rod and the end of the rivet, and the joint did not lock solid with solder - amazing !! Moreover, the same result was achieved with the second rod.

 

Into the ultrasonic cleaner for three minutes to remove any dross, and a pair of gleaming rods emerged. The joint action was a little stiff, so a touch of Brasso was applied and the joints vigorously worked until they became a little more free.

 

Back into the ultrasonic cleaner; dried, oiled, and the rods passed the 'drop under gravity' test for free action.

 

 

The glue on the Poppy's jig should be dried in time for the next session, so it'll be on with the main frame erection.

 

Regards,

John Isherwood.

Edited September 17, 2016 by cctransuk

[cctransuk]

The glue on the Poppy's jig should be dried in time for the next session, so it'll be on with the main frame erection.

 

Well - the glue dried and out came the soldering iron.

 

Now - lets make one thing clear; I'm a Luddite when it comes to chassis !! Strictly rigid 16.5mm. gauge, all as per Tony Wright's creed. I have tried equalised and sprung, and have produced sweetly running chassis - but no better than the rigid ones that I build, so what's the point?

 

The frames were detached from the fret; the tags filed off; the axle holes opened out to fit the top hat bearings; and the brake gear support holes opened out to suit the prescribed 2mm. OD brass tube; both using tapered broaches. It was also necessary to remove two of the four tabs on the underside of the front of each frame; these tabs fit into slots in the front 'mudguard' spacer, and the tabs to be removed will be dictated by the gauge for which the chassis is being built. Think about this carefully, and then think again before removing the surplus tabs; (guess who removed the wrong rear tabs)!

 

I have to say that. IMHO, the frames are a little thinner than I would have preferred. I know that this is all the rage nowadays, but the chassis ends up far too 'bendy' for my liking.

 

Anyway, the top hat bearings were soldered in place; and cut and filed off flush on the inside of the frames. What a difference to the ease of soldering nickel silver makes when compared to brass ! I don't like axle bearings left too long, especially on thin frames which can, to some extent, be a little flexible - they can be an unnecessary source of binding if left over-long.

 

 

The frames were now set up in the Poppy's jig, and one problem immediately surfaced; there is no provision that I could see for setting up a 7'0'' - 7'9'' wheelbase frame. Both 7'9'' markings are obstructed by solid MDF. I was therefore obliged to very carefully 'drift' the end of one of the slots with a round needle file, taking great care to keep the horizontal alignment of the slot.

 

 

Having achieved the set-up in the jig, the rear, and intermediate frame spacers, plus the front 'mudguard' spacer were removed from the fret and their tags were removed; plus the rear spacer was folded to form a square 'U'. Starting from the rear, the spacers were fitted and soldered into place - their tabs just snap into the frame slots with a little pressure. Lengths of 2mm. OD brass tube were also passed through the appropriate holes in the frames and soldered in place. In no time at all the basic chassis was assembled and removed from the jig.

 

 

Markits' wheels were assembled in the chassis, having slightly relieved the axle holes in the bearings with an 1/8'' reamer. Markits' threaded crankpins were screwed into the wheels, and the coupling rods were tried in place. Some initial stiffness was eliminated by slightly opening out the crankpin holes in the coupling rods - I always leave the holes as a tight fit on the retaining bushes when assembling the rods, and then open them out with a taper reamer - a little at a time - until the wheels / rods rotate smoothly with no binding.

 

As the rods are thicker than the bearing width of the retaining bushes, I counter-bored the outer faces of the bearing holes in the rods with a 3mm. drill. The retaining bush heads are therefore partially recessed into the face of the rods, which will make the fitting of the coupling rod 'hub-caps' much easier at a later stage of construction.

 

 

At this point, I had a rolling chassis - next will be the assembly of the motor and gearbox.

 

Regards,

John Isherwood.

[Enterprisingwestern]

 

 

The frames were now set up in the Poppy's jig, and one problem immediately surfaced; there is no provision that I could see for setting up a 7'0'' - 7'9'' wheelbase frame. Both 7'9'' markings are obstructed by solid MDF. I was therefore obliged to very carefully 'drift' the end of one of the slots with a round needle file, taking great care to keep the horizontal alignment of the slot.

 

 

 

As good and inexpensive as the wooden jig may be, it's great disadvantage over the infinitely variable Eileens/Hobby Holidays jig made from metal is precisely that.

Not that I need a jig, but I reckoned the Poppys one was a tad deficient in the ability to do small shunter wheelbases with jackshaft drive, although my observations could well be erroneous of course.

 

Mike.

 

Mike.

[cctransuk]

As good and inexpensive as the wooden jig may be, it's great disadvantage over the infinitely variable Eileens/Hobby Holidays jig made from metal is precisely that.

Not that I need a jig, but I reckoned the Poppys one was a tad deficient in the ability to do small shunter wheelbases with jackshaft drive, although my observations could well be erroneous of course.

 

Mike.

 

Mike.

 

I have little or no knowledge of the Eileens / Hobby Holidays jig, but on the face of it I would worry about working clearance / backlash in a device that apparently relies on just one set of coupling rods to set the position of axle bearings.

 

If I am interpreting how the jig works - apologies; but I know how careful I have to be to eliminate backlash with my Unimat 3.

 

Regards,

John Isherwood.

[Horsetan]

I have little or no knowledge of the Eileens / Hobby Holidays jig, but on the face of it I would worry about working clearance / backlash in a device that apparently relies on just one set of coupling rods to set the position of axle bearings.....

What's wrong with assembling both sets of coupling rods and checking them one after the other?

[Enterprisingwestern]

I have little or no knowledge of the Eileens / Hobby Holidays jig, but on the face of it I would worry about working clearance / backlash in a device that apparently relies on just one set of coupling rods to set the position of axle bearings.

 

If I am interpreting how the jig works - apologies; but I know how careful I have to be to eliminate backlash with my Unimat 3.

 

Regards,

John Isherwood.

 

To continue from Ivans post.

It's a lot more bomb proof than that John, once you've assembled one set of rods and set the jig up, then the frames and other set of rods can be built from it, To build the frames the coupling rods aren't actually needed to keep anything in alignment.

 

Mike.

[cctransuk]

To continue from Ivans post.

It's a lot more bomb proof than that John, once you've assembled one set of rods and set the jig up, then the frames and other set of rods can be built from it, To build the frames the coupling rods aren't actually needed to keep anything in alignment.

 

Mike.

 

Ahh - I see !

 

Having just seen photos of the jig with a single set of rods attached, I made incorrect assumptions.

 

I have to say that I have had no real problems assembling etched rods and frames without any sort of jig, or using just a set of extended axles with turned-down ends to suit the crankpin holes in the rods.

 

The Poppy's jig is merely an extension of this idea, but does provide an excellent way of holding everything in place whilst the frame spacers are fitted and soldered.

 

If I loose the touch as I age, perhaps the Eileens / Hobby Holidays jig will prove to be the answer.

 

Regards,

John.

Edited September 20, 2016 by cctransuk

[cctransuk]

The gearbox provided with the chassis is, not surprisingly, a High Level product; and the motor is a Mashima 1430. As is now well known, Mashima are about to / have ended production permanently, so alternative sources for motors will have to be found in future.

 

I have been providing cheap but high quality Japanese Mitsumi motors for some time now; (see http://www.cctrans.org.uk/ and http://www.rmweb.co.uk/community/index.php?/topic/98857-building-a-4mm-scale-mpd-midland-3f-0-6-0/ ); and I wanted to be able to test one in this chassis. So I drilled two extra holes in the gearbox frame to suit the Mitsumi motor fixing holes.

 

 

Having removed the gearbox frame from the etch, it was folded to shape, and the rest of the components were assembled as per the instructions; it really couldn't be simpler.

 

The Mashima motor was fitted in place in the gearbox, and then the assembly was lightly lubricated and tested under power - all was fine so far.

 

 

 

 

Next, the rolling chassis was partly dismantled in order to fit the motor / gearbox, and then reassembled.

 

Power was supplied via long, thin wander leads, and the chassis was placed on the track. Slowly turning up the throttle, the chassis duly trundled off down the track - and very smoothly at that !

 

 

Next time, pick-ups, so that proper track testing can be undertaken.

 

Regards,

John Isherwood.

Edited September 22, 2016 by cctransuk

[cctransuk]

GT3 will not, when completed, have pick-ups; I intend to use the 'American' system of electrically separated loco and tender. To this end, the LH loco drivers are uninsulated and so the loco chassis is live.

 

Nonetheless, it is much more convenient whilst building the loco to be able to test it independently; ie. without the tender attached.

 

So, I set about building and fitting a set of pick-ups for the RH, insulated loco driving wheels.

 

 

The pick-up mount comprises a strip of single-sided copper-clad paxolin cut slightly wider than the distance between the frames. I scribed two grooves, with an Olfa PC-S plastic cutter; ( http://www.olfa.co.j...detail/157.html ); in the non-copper side of the paxolin, to match the frame width. These grooves were to half the thickness of the Paxolin; then two more cuts were made, just outside the grooves, to the full thickness of the paxolin. A little tidying up of the edges with a needle file produced stepped edges to the paxolin which allowed it to sit half within the frames and half on the lower edge of the frames.

 

On the copper side of the paxolin, a longitudinal groove was cut approximately 3mm. from what would be the RH edge; four 1mm. holes were also drilled through the paxolin for ease of making electrical connections from above the frames.

 

The paxolin was tried in place below the frames, and the position of the frame spacer which prevented it sitting down into the frames was marked. A groove was scribed into the paxolin to take the frame spacer, and a 2.3mm. dia. hole was drilled along the axis of the paxolin, and offset 1.0mm. from the groove for the frame spacer. An 8BA thin headed screw was then passed through the paxolin from the copper side, and a brass nut was screwed in place on the plain side.

 

The lower edge of the frame spacer, and the appropriate face of the fixing nut were both tinned, and then the paxolin was put in place below the frames. A spot of flux was applied to the joint, and then a hot soldering iron was touched to the frame spacer and nut. The positions for the pick-ups were marked on the RH edge of the paxolin, to line up with the upper edge of the wheel flanges.

 

 

The paxolin could now be removed by unscrewing the 8BA screw, and the copper faces were tinned and checked to ensure that the narrower and wider strips were electrically isolated.

 

The pickups themselves are phospher-bronze strip. One end was tinned and soldered to the first pickup position, and then bent up tight to the edge of the paxolin. The strip was cut off 20mm. from the bend, and the end which will rub on the wheel flange was centre-punched to form a dome. This was repeated for the remaining two pick-ups, and two lengths of thin insulated wire were soldered to the two sections of copper, via the 1mm. holes previously drilled.

 

 

 

The pick-up unit could now be reattached to the chassis, ensuring that the strips passed between the wheels and the frames. The strips were 'tweaked' to ensure that they did not touch the wheel backs or the frames, and that the domed portion rubbed on the flange edge. Clear adhesive tape applied to the face of the frames can assist here.

 

The wires were soldered to the motor terminals, and the chassis was placed on the track with some temporary weights to aid adhesion.

 

 

 

Power was applied and, very gratifyingly, the chassis glided off down the test track virtually silently - just the noise of wheels on rails and the occasional rail joint click.

 

It is a testament to the design of this chassis kit that the foregoing build has taken less time than it has taken to compile this thread !!

 

Next time - brakegear.

 

Regards,

John Isherwood.

[ozzyo]

Saw this photo and thought of this thread.

 

OzzyO.

[Mike Riley]

John,

 

Looking at this picture I don't see the washer between the idler gear and the left side of the body.  I think that is why it is not fully engaging with the final gear.  The washer is included on the etch.

 

The High flier is my favourite - I have a number of them and they work beautifully.

 

 

Mike

[cctransuk]

John,

 

Looking at this picture I don't see the washer between the idler gear and the left side of the body.  I think that is why it is not fully engaging with the final gear.  The washer is included on the etch.

 

The High flier is my favourite - I have a number of them and they work beautifully.

 

 

Mike

 

Mike,

 

You are quite correct - I should always read the instructions !

 

I am awaiting a lower ratio gearset fro High Level - GT3 runs a little too sedately for my taste.

 

I'll fit the spacing washer when I exchange the worm and pinion.

 

Regards,

John.

[cctransuk]

Building and fitting brakegear - a trifle fiddly, but what could possibly go wrong; (that would account for the delay in posting this episode)?

 

Following the instructions - now there's a novelty - I assembled the three layers that make up the brake hangers / shoes, remembering to produce three each of the LH and RH assemblies. Alignment of the back and centre laminations was achieved using drills through the outer holes, as with the coupling rods; the outer brake shoe lamination was aligned using a length of 0.7mm. brass rod, which was cropped off after the laminations were soldered together, to represent the shoe fixing.

 

Conductive brake hangers and brake rods are always a recipe for short circuits, so I decided to attach the brakegear in such a way that it was electrically 'dead'. To this end, the 2.0mm. brass tube brake hanger supports were cut off flush with the outer face of the frames, and three 17mm. lengths of 1.6mm. Evergreen plastic rod were cut. These were drilled at each end, 0.7mm. axially, and then inserted into the brass tubes with equal lengths protruding from each side. The plastic rods were then locked in place with a touch of cyanoacrylate glue. The brake hanger / shoe assemblies could now be attached to the ends of the plastic rods with short 14BA screws, which self-tapped into the 0.8mm. axial holes.

 

Ooooo-er !!     The brake shoes were a country mile from the wheel treads. Somewhat belatedly, I checked the diameter of the Romford wheels that I'd had stashed away for this project for ages - and they turned out to be 5'-6'' (22mm.) diameter instead of the correct 5'-9'' (23mm.) of the prototype.

 

Cue a quick call to Wizard Models, who could supply six of the correct wheels, albeit all insulated. The 'American' system of insulated loco and tender relies on having the respective chassis live; something not easily achieved with all insulated driving wheels. So, whilst awaiting the delivery of the replacement wheels, I added an additional set of pick-ups to the copperclad strip below the frames, and isolated the screw which attached the copperclad to the chassis.

 

 

The replacement wheels were fitted, resulting in a much more intimate relationship between brakeshoes and wheel treads.

 

The brake pull rods could now be soldered in place, and the brake actuating assembly was soldered into the trunnions below the rear of the frames. The rear ends of the brake pull rods were not attached to the actuating assembly, so as to ensure that they remained electrically isolated.

 

 

Note that, contrary to the instructions, GT3 had two loco brake cylinders located outside and to the rear end of the frames. I therefore fabricated two brake cylinder levers from strip brass, attaching them to the ends of the brake actuating assembly. Brake cylinder rods, made from 0.8mm. brass wire, were soldered to the levers, but the actual cylinders were omitted as they are hidden behind the cab footsteps.

 

So - a slight hiatus resulting from not checking basic components, but easily remedied thanks to prompt service from Wizard Models.

 

Next, and last stage in the chassis assembly, the front bogie; with which I intend to depart slightly from the instructions and adopt a sprung mounting which applies the load below the axle centreline; (with due acknowlegements to Chris Gibbon of High Level Models who kindly supplied the sketch below).

 

 

Regards,

John Isherwood.

Edited October 1, 2016 by cctransuk

[cctransuk]

Firstly, apologies for any muck evident in the photos - my Lidl ultrasonic cleaner has gone on strike again !!

 

Right - the front bogie ! Assembled exactly as per the instructions, easy - except that I forgot that I was going to install the bogie with spring-loading onto the lower plate, and that this would require slots across the frame cross-members !

 

   UNDERSIDE

 

  TOP

 

The resulting slots are not as neat as they would have been if I'd cut them in the flat etch. The upper slot is a wide, clearance width for the spring; the lower slot is to take a 2mm. ID top-hat bearing as a sliding fit.

 

 

 

The mounting pillar is an 8BA cheesehead screw, the head of which matched the hole in the chassis top etch.

 

The spring is, I believe, one of those supplied with spung three-link couplings, and is a perfect fit onto the smaller outer diameter of a 2mm. ID brass top-hat bearing. The bearings themselves slide freely on the 8BA screw.

 

Another 2mm. ID top-hat bearing slides in the lower bogie plate slot, and the whole arrangement is held in place by an 8BA large washer and nut.

 

In this way, spring pressure is applied below the axle centreline, resulting in a very stable bogie; the spring length can be adjusted to avoid excessive transfer of adhesive weight from the driving wheels.

 

The bogie was fitted to the chassis and a test run was made - with less than satisfactory results ! Short-circuits in considerable number were noted - particularly between the flanges of the bogie wheels and the underside of the chassis top plate; (the bit with the mudguards). In fact, clearance at these points was zero - why?

 

Back to the Markits driving wheels; which you will recall had initially been incorrectly fitted as 5'-6'' (22mm.) diameter, and were then replaced by nominally correct 5'-9'' (23mm.) diameter. However, measurement with a micrometer showed that they are, in fact, 22.68mm.diameter. Only 0.32mm. undersize, but enough to lower the chassis top plate onto the bogie wheel flanges.

 

Tim Shackleton, who published his GT3 build in Hornby Magazine, used Gibson wheels apparently without problems. So, if you too are going to use Markits wheels, I would recommend ordering 6'-0'' (24mm.) diameter wheels - which will probably be spot-on for 5'-9'' (23mm.).

 

I was not prepared to order yet more wheels for my model, so some drastic surgery was required to accommodate the bogie wheel flanges.

 

 

You will see that I cut large sections out of the chassis top plate, and soldered in a new front spacer plate to restore some rigidity to the frames.

 

In the interests of eliminating all short-circuits, I revisited the pick-ups. The phosphor-bronze strip back-scratcher pickups can work well, provided that there is plenty of clearance between the frames and the back of the wheels; in this case, there wasn't. So I made up a set of traditional phosphor-bronze wire flange-edge wipers, and fitted these in place of the original pick-ups.

 

 

I also noted that the brake pull rods had only a fag-paper clearance on the wheels. Rather than rebuild the brakegear I took the easy way out; cutting the cross-rods at their centres and using telescopic brass tube to space the two sides a little further apart.

 

 

Finally, I decided to substitute one of my Mitsumi motors for the Mashima that had been supplied, as I find that the former run exceptionally quietly. Whilst undertaking this motor change, I fitted a lower ratio worm / idler pinion set into the High Level gearbox to slightly increase the top speed of the chassis, and a torque arm was soldered between the gearbox and the chassis.

 

 

After all that modification - which was entirely due, I am sure, to my insistence on using Markits' wheels - I finally had a smooth-running, almost silent chassis with a realistic top speed.

 

 

Regards,

John Isherwood.

 

PS. As you can see, I also fitted the balance weights.

Edited October 5, 2016 by cctransuk

[cctransuk]

A little more progress today, and effectively the end of the High Level chassis build.

 

The tender inner chassis is a very simple fold-up item, especially if, as I did, you build it rigid with a little up / down allowance for the centre axle !

 

I opened up the axle holes to take 2mm. ID brass top-hat bearings, and soldered the bearings into the front and rear axle holes. I extended the centre axle holes a little in a vertical direction, both upwards and downwards, so that the top-hat bearings could move smoothly up and down.

 

The inner chassis etch was then folded into a rectangular U shape; (the etch has relieving slots to assist in folding); and the folds were reinforced with solder on the inside.

 

 

Four lengths of 0.8mm. brass wire were soldered into the holes in the half-etched outline of the brake hangers / pull rods, to stabilise the inner chassis, and a length of thicker brass wire was soldered into the brake shaft trunnions.

 

As the dummy outside tender frames will completely hide the notional brakegear, I did not feel that I needed to add any more substantial representation of the brakeshoes.

 

 

Job done !

 

Next, I think I'll be gettng out the Ian Macdonald detailing etch, and assembling the tender outside frames.

 

Regards,

John Isherwood.

[stewartingram]

What did the gear ratio end up as John?

 

Stewart

[cctransuk]

What did the gear ratio end up as John?

 

Stewart

 

Stewart,

 

Do you know - I'm not sure !!

 

I discussed decreasing the ratio with Chris Gibbon, and he said that he would send me a replacement worm / idler gear.

 

..... I suppose that I could count the teeth on the idler - I'll try and remember to do so tomorrow.

 

If you need to do the same thing, Chris will be able to tell you what he sent to me.

 

Whatever it is, it's done the trick !

 

Regards,

John.

Edited October 6, 2016 by cctransuk

[cctransuk]

Just a short report today.

 

In order to emboss the rivets on the tender outside frames, I got out my homemade rivet press; which I mount in the vertical drill stand of my Unimat 3.

 

Having done the rivets very quickly I decided, whilst the lathe was out, to turn up a 20 x 7.5mm. brass flywheel, to hang on the spare shaft of the Mitsumi motor.

 

 

Glad I did, the improvement in the driveability is amazing - you really get the impression of taking up the load, and having some considerable mass to control.

 

Regards,

John Isherwood.

Edited October 6, 2016 by cctransuk

[Guest Isambarduk]

"..... I suppose that I could count the teeth on the idler - I'll try and remember to do so tomorrow."

 

No point in doing that really, as an idler does not contribute to the overall gear ratio at all; it's the number of starts on the worm and the number of teeth on the worm wheel that matter.   Unless the idler isn't an idler gear but a pair of gears on the same shaft with a different number of teeth, one to engage with the worm and the other to engage with the final drive gear on the axle.  David

[cctransuk]

Unless the idler isn't an idler gear but a pair of gears on the same shaft with a different number of teeth, one to engage with the worm and the other to engage with the final drive gear on the axle.  David

 

...... which it is - as per, I think, all High Level gearboxes; except that in this case there's a secondary idler stage too.

 

That's the point of replacing the worm / wormwheel-idler - that pairing dictates the ultimate gear ratio.

 

Regards,

John Isherwood.

[Michael Delamar]

Shot of the real thing under construction.

 

[cctransuk]

Shot of the real thing under construction.

 

image.jpg

 

Excellent shot, isn't it ?

 

Note too, that it appears that English Electric fabricated the brake shoes from the pile of etched laminations in the foreground !!

 

So this 4mm. scale chassis must be merely a scaled down version of the prototype 1:1 artwork. The original would have been hand-drawn too, as digital design had not then been invented.

 

I didn't know that High Level Models was even in existence then; let alone subcontracting to EE - they must have needed huge sheets of brass.

 

Regards,

John Isherwood.

[cctransuk]

Today it was the turn of the tender.

 

Ian Macdonald's tender chassis kit goes together like a dream - I am using it in a cosmetic role -  and the High Level functional inner frames fit within it with no problems whatsoever. Round-headed sprung buffers, from a set of Markits' LMS Duchess buffers, were soldered to the chassis; and I now await the arrival of a set of Gibson BR tender springs / axleboxes.

 

 

 

 

 

A tiny amount of flash was removed from the Golden Arrow tender body moulding, which then slid into place over the locating / fixing panels of the cosmetic chassis. A few oddments of lead glued to the chassis to assist track-holding completed the principal tender work.

 

 

Regards,

John Isherwood.

Edited October 9, 2016 by cctransuk