Nick Dunhill's 7 mm workshop, M&GN Melton Tanks

[nickd]

 

Time for a new build.  This project is the construction of 2 M&GN 4-4-2T Melton Tanks  (LNER C17).  They were built in Melton Constable from 1904 and survived into the 1940s.  They were built using many parts from MR locos.  There is an ACE Kit available that I'm sure will build a perfectly acceptable model, but for this project some custom etches were commissioned (available on request.)

 

 

My original plan was to build a donor ACE kit body on the chassis and footplate etches above.  But on reflection I considered it prudent to commission more etches for a basic body (more later.)

 

The chassis etches follow prototypical practise and are in three overlapping sections pinned together by the drag box or frame stays.  All the stays are prototypical allowing easy fitment of other parts such as brake cylinders and inside valve gear.

 

 

 

 

Next the valences and buffer beams were soldered to the footplate to give a flat rigid structure.

 

 

 

The drag beams for the couplings are in interesting places.  The rear coupling is attached to it's drag box under the cab and the front coupling is attached to the front drag box which is part of the valve chest/ cylinder block.

 

 

 

 

And I have made them sprung.

 

 

more fun soon......

Edited July 28, 2019 by nickd

[sej]

That's a lovely loco Nick, both prototype and etches! What inspired you to model it?

 

Cheers

Simon

[nickd]

Hi Simon

Someone asked me to.

Simple as that, it is a handsome loco though.

Nick

[sej]

Thanks Nick, did you draw the etches?  They look very well designed.

 

Cheers

Simon

[nickd]

They're done by my mate Mick Davies, who also draws the etches for Finney7.

[nickd]

....so on with the show!  Well this week a lot has been done, although the project doesn't seem to have moved on much.  The footplate has had lots of angle fitted, as per prototype, which would on the real thing reinforce the buffer beam/valence/footplate structure.  The angles being present between frames and buffer beam have necessitated the buffers being modified.  They are Slater's MR Kirtley short buffers with packing pieces, and have been converted to being self contained.  This is quite a lengthy task.

 

 

 

 

The steps were added next, along with the frame extensions above the footplate.  This required copious amounts of tea.

 

 

 

Laurie Griffin does some cast horn blocks and guides.  They take a lot of fettling to make them work nicely, but are excellent when finished.  Crucially they are very, very similar tho the real ones.  The axle boxes were lightly modified to grasp the horn cheeks (rather than running in a slot, like other makes) and have a nice keeper plate too.  I will endeavour to use them again.

 

 

 

The balance weights for the wheels were marked out and cut from NS sheet, loco no.41 has boxy pattern ones and the later no.9 loco has more conventional curvy ones.

 

 

 

And as usual you spend days prepping stuff and then a lot happens in one day.  The horn guides and axleboxes were assembled in the chassis using jury axles and the coupling rods as a jig.  Note that I temporarily braced the chassis with some scrap strip to prevent the springs locating the axlebox assemblies spreading the chassis.

 

 

 

 

Using this method and with careful alignment of the axleboxes, a smoothly running chassis results.

 

 

And finally a gratuitous bedroom shot.

 

 

Bogies and radial trucks next......

Edited August 3, 2019 by nickd

[RLWP]

Those lumps of wood work hard

 

Lovely work, Nick

 

Richard

[nickd]

....there are no parts in the etchings for bogies or radial/pony trucks, so out with the saw.

 

 

 

So I marked one out cut it from the sheet and soldered it onto another sheet, cut round it......etc, etc.

 

 

 

The die block is made from telescoping square and round sections of brass, as I have no lathe.

 

 

 

The axleboxes and equalising beam springs are harvested from a set of LGM LSWR cast bogie side frames.

 

 

 

 

I cut out my own equalising beams from scrap etch.

 

[nickd]

And here is a finished bogie complete with side control.

 

 

 

 

I checked the wheelbase on a 6' radius curve and it just squeeks through.  a couple of mm to spare!  This is mainly because the frame is solid behind the rear bogie wheel, but a miss is as good as a mile, as they say......

 

A look at the drawing revealed the trailing wheel to be held in a pony truck, and not a radial truck as I had assumed.  Again no etched parts so...

 

 

 

A bit of drilling and sawing later we have a basic pony truck.  Will detail it in a couple of weeks after my holiday, yay!!

 

 

[nickd]

...back from my windy holiday in Orkney and on with the show.  I have added all the side control for the rear pony truck.  I just followed the drawing, what I have built is very similar to the real thing.  There's a downward spring to help it all along too, and some dummy leaf springs.

 

 

 

I also added some prototypical bump stops on the banana shaped brackets poking out of the front of the motion support frame stay.  They limit the travel of the rear of the bogie so that the rear bogie wheels don't hit the frame, as there are no-cut outs in the frame for the rear wheel.  I then had a bit of a test run and all was well.

 

 

 

It ran nicely on a 6' rad curve, with no shorting, and a bit to spare too.  Happy days, the rest is just cosmetic.  Do you like my Heath-Robinson test track, it's sitting on a Templot printout (thanks Tony!)

 

Now on to the springs and hangers.  The hangers are etches on the body etch, and the springs and rubber bumpers are from an LGM set of Princess Royal castings.

 

 

 

 

 

 

The springs for the front wheels are removeable because I'll need to drop out the axle when the inside motion is fitted up.  

 

Talking of which, to bring me up to date;

 

 

 

Here's one in a jig so I can solder the ends on the eccentric rods reasonably accurately.

 

More this week, and then off to Telford.  See you all there on the Modelling Competition Stand...........

Edited August 26, 2019 by nickd

[nickd]

...so back from Telford and on with the valve gear.  It's standard Stephensin link motion from the Laurie Griffin range, it needs a bit of modification but nothing drastic.  Wooden jigs were made for making the rods and drop links.  I thought the new style cast eccentric sheaves would be a nightmare but they cleaned up very nicely. 

 

The trick with valve gear is to assemble it carefully so everything is straight and in alignment, and theres a good chance it won't bind.  Cross drill everything carefully.

 

 

 

 

 

 

 

It worked well, so I moved on to the outside cylinders.  I built the connecting rods, then ran out of castings for the cylinders, ordered new ones and moved on to the ashpan.

 

 

 

The ashpan is fabricated from the waste round the etchings.  Measure, measure, cut, cut, solder, solder.  I like to make the lower part of the firebox too.  It partly hides the motor and gearbox.

 

 

 

And here's the assy. installed in the frames.

 

 

 

 

And finally I cut out the brake parts ready to go.

 

 

Brakes and outside cylinders next........

[nickd]

......I have made the brake system.  Mainly scratchbuilt.

 

 

 

[nickd]

......well now the NGG16 is in Canada at it's new home and the W1s are delivered too, it's back to this.  I have been looking forward to building the cylinders, and there were some basic bits in the etches for the cylinder block.  So I bought some bolt heads for the cylinder covers and scratchbuilt some slide bars.  I used crossheads from the ACE rendition of this loco.

 

 

 

 

 

I scratchbuilt some slide bar support brackets and closed up the cylinders with rectangles of thin nickel silver sheet.

 

 

 

 

 

Next job is the cylinder drain cocks and operating levers, sanding pipes and to finish the chassis some vacuum brake fittings.  Then the bodies.......

[nickd]

.....now the chassis is nearing completion and won't be handled too much I have put on some of the more delicate bits.  I have added the cylinder drain cocks and their operating levers, the sanding pipes and the plumbing for the vacuum brakes.

 

 

 

The sanders have the steam pipes added too.

 

 

 

 

This marks the end of the chassis build, so a big wash tomorrow and on with the bodywork........

[nickd]

...bodywork!  Started with the beading round the cab (riveted strip on the inside) and went on to the tank tops and beading, all well so far.  I solder a strip of waste strip over the half etched lines on the body sides.  This prevents them getting bent by mistake, especially the half etched line for the cab rear.  It's very close to the return that has to be formed for the cab doors.

 

 

 

 

The cab doors were made, and then promptly taped shut to prevent damage.  I then made and detailed the cab front and rear and splashers.

 

 

 

 

 

Next the tricky bunker rear and attaching everything to the footplate without tabs and slots!

 

[nickd]

....massive leap today, or so it seems.  Actually all the preparation was done towards the end of last week.  I did a lot of measuring up , and you can see that I have soldered some small lengths of scrap onto the footplate as a location guide for the sides.  Remember the footplate and body sides have no tabs and slots.  The cab front, rear and floor were attached, and then the other side.  Finally the bunker floor and rear panel and beading.  I have added tapered handrails to the cab side, and steps to the tank front.

 

 

 

 

 

 

 

Next I will (catch the other loco up) add some more cab detail, build a cab roof and close up the insides of the water tanks.  Then it's just the boiler to go.......

[nickd]

.......next I added all the angle iron bits of strapping round the various parts of the cab, and cut out a paper roof template.

 

 

 

I continued with the theme of strapping and angle onto the underside of the cab roof, and they formed a good way of locating the roof on the cap top.

 

 

 

Next, more cab stuff........

[nickd]

I have fitted out the cab.  Planking on the floor (sorry WH, customer preference) handbrake stancion and backhead.  Theres a couple of lubricators that aren't in the photos, but cab interior is done.  All the backhead stuff is from Laurie Griffin.

 

 

 

 

More water tank action next........

[nickd]

....the plan is to glue strips of lead sheet inside the tanks and then close them up.  I thought it prudent to build splashers inside the tanks first.

 

 

 

 

 

I thought it'd be a good idea to build up the loco as built so far to check all fits, and it does!

 

 

 

 

It is such a little simple loco in comparison with the brutish W class in my other build!  If you are going to Reading on saturday come and have a look at it.  Just the boiler to go!......

[nickd]

....boilers!  The etchings Mick D did for me already had some of the boiler/firebox/smokebox formers included, but I needed extra ones and cut them from 0.4 mm nickel silver.

 

 

Firstly I made the smokeboxes.  The etches did have parts for the wrappers too, so this job was pretty easy.  Form the wrappers into shape round suitably sized bar/drill shanks and solder up.  The main curve I did by hand using a 20mm bar.  Then I introduced a former and marked the positions of the reverse curves.  The reverse curves were (slightly over-) done with a 7 mm drill shank.  The wrapper was centred over the formers, and the formers brought to the front edges of the wrapper using a steel rule layed across the edges, you'll need to use your 3rd and 4th hands!  Tack the main curve of the wrapper to the formers and then carefully unfold the return curves to match the lower parts of the formers.

 

 

 

The boilers are a lot easier.  A rectangle of 0.3 mm nickel silver was cut.  {lenght required x [(diameter of former-thickess of material) x pi]}.  This was shaped on my slip rollers.  Put the ends of the sheet backwards through the rollers first to form the required curve.  This prevents the rollers producing a flat end section to your tube.  See here: 

 

https://www.youtube.com/watch?v=Vw8cuGUQZrU

 

 

The boiler bands were added from 0.2 mm strip (I know, I just like adding boiler bands) and cast tightening cleats soldered on.  The boiler furnature castings were (extensively!) fettled and test fitted.  (Do we all know the trick of laying abrasive paper round the boiler and 'lapping-in' the curved fixing flange of a chimney or dome?)  

 

Note to pattern makers and casters, please please please stop making chimneys that are solid down the middle.  It takes ages to bore them out, it has to be done by hand because you can't hold them in anything.  Brass cast ones are just impossible to bore out and I just weigh them in.

 

 

As a finishing touch I scored the boiler clothing plate join along the top of the assembly and added some fake set screws.

 

Next I finish the build with the last boiler details and some tablet catchers.......

Edited December 24, 2019 by nickd

[nickd]

Oh, the holes in the footplate ahead of the tanks are for some home made oil pots.

 

 

[nickd]

......Just been pluggin' away with this one adding all the bits of boiler details.  There's a interesting stay between the water tank and boiler.  I cut holes in both and devised a small plate to represent the stay itself.

 

 

 

 

I sorted out the smokebox doors.

 

 

Or so I thought until I realised the short smokebox has a different door and handles.  Which was a bit irritating because the ACE casting has a disc on the back and I had to cut a hole in the front of the smokebox to accommodate it.

 

 

Had some fun making door handles though.

 

 

I spent a few hours making copper pipework for the lubrication system (to be added later after paint,) and these rather nice Whittaker Tablet catchers from MOK, cheers Dave!

 

 

Next week we finish them.......

Edited January 10, 2020 by nickd

[nickd]

.....things have moved on a lot this week.

 

 

First I sorted out the safety valves and built a whistle mechanism.  The loco had some stats between the boiler and water tanks.  I cut out the areas to accommodate them earlier, and attached the plates, with some fake fastners, this week too.

 

 

The steam pipe covers were next.  They were a long job.  DLOS machined me some basic brass shapes and I made (several) sets of bolt plates and attached them to the footplate, chassis and smokebox.

 

 

The bolt flanges were pre drilled for the fake fastners too.  The machined brass parts were carefully shaped to match the profile of the smokebox and soldered in place.  90deg solder acts as a good filler for the small gaps.

 

 

 

Lastly the fastners were added.  The one in this pic needs a good clean!

 

 

The next job on the list was the vacuum ejectors.  I couldn't find a good casting out there so scratchbuilt some, mainly from telescoping tube.

 

 

Here's one of the finished items fitted up to the boiler and handrail.  I added a control rod too.

 

 

 

Lastly the locos aquired lubricators and a jack.

 

 

 

The locos are basically finished appart from pickups, a test run and a good wash.  Hopefully more pics of a finished loco soon........

[Scale7JB]

Looking great, Nick!

 

JB. 

[nickd]

....here we are at the end of construction.  I have fitted the pickups and done a test, and both run very nicely round a 6' curve, no shorts etc.

 

 

 

There's odds and sods of pipework to be added post paint. 

 

 

I realised I'd forgotten the reach rod for the reversing links, oops

 

 

More pics here; https://www.flickr.com/photos/144381574@N05/

 

I'll have number 41 at Bristol on sunday if you want a closer look, see you there (sharing a stand with Warren Haywood).........

Edited January 24, 2020 by nickd