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Designing & Building Great Central Locomotive Kits

Posted: Sun Oct 30, 2011 11:54 am
by John Bateson
And so it continues ...
After a lot of thought, the next model in the series of Robinson 4-6-0s will be the Class 8F or LNER B4 (Immingham class as it was known).
There was a possibility of a serious diversion from the 4-6-0 theme, the Jersey Lillies and 'Tinies' being among those locomotives for which I have had enquiries, feasible because of the common parts with the Class 8 "Fish" engines which are now on the market.
I was pleasantly surprised at how little time it took to progress the Class 8F using the parts already designed, only 2 days into it and the chassis design is nearly finished so in the future it may be that other locomotives that shared these parts may move up the to-do list.

And after several days of packing boxes, the lady downstairs has suddenly taken up her knitting and crochet work again!

John

Re: Building another Robinson 4-6-0

Posted: Thu Dec 22, 2011 4:19 pm
by John Bateson
Does anybody in S4um land have a good picture of the reverser gear as fitted to Robinson locomotives - I would like to produce a 'printed' version for my kits rather than rely on the usual offerings which seem not quite as good or as accurate as they might be.
It appears as though the real thing might just be an unequal 'U' with a screw at 3.5 degrees - the screw being open to the atmosphere and not covered in.
John

Re: Building another Robinson 4-6-0

Posted: Mon Dec 26, 2011 5:37 pm
by John Bateson
After some work and avoiding relatives here is what I think might make a reasonable composite for the GCR locomotives reversing gear.
Note the perspective is switched off for these pictures.
Comments would be welcome please.
246 Reversing Gear 1.PNG
246 Reversing Gear 2.PNG


The locking mechanism is the later version, the original seemed to be just a small thing like a trigger. Also I am starting to wonder if there is actually more than one major type. I have drawn this one with a supporting central web rather than a full overall cover.
The good news is that this will print in 3D but before I commit a lump of money to this any expert advise would be most welcome

John

Re: Building another Robinson 4-6-0

Posted: Thu Jan 19, 2012 2:42 pm
by John Bateson
Proceeding apace on the etches for the B1, B4 and C4 (yes, I know the last one is an Atlantic - Jersey Lily) - but there are quite a few similarities that I have been persuaded this class should be added to my compendium.
The chassis etches for these three are now with the etchers somewhere to the north of here and I will then have the task of building the chassis and checking the instructions.
And I have had instructions from the Lady Downstairs to get my a*** into gear and move into the larger bedroom for the office and workshop facilities - just at the time she is disappearing off to Crawley for 10 days!

John

Re: Building another Robinson 4-6-0

Posted: Wed Jan 25, 2012 4:13 pm
by John Bateson
Still struggling with the body for the Class 8F but the name plate looks almost right, so I'm sticking with this
John
004 Robinson B4 V1.0.PNG
Name Plate for "Immingham", the only one of the 8Fs to be named

Re: Building another Robinson 4-6-0

Posted: Wed Jan 25, 2012 11:07 pm
by HowardGWR
John Bateson wrote: - just at the time she is disappearing off to Crawley for 10 days!

John


What, for the football? They are doing rather well I admit.

Re: Building another Robinson 4-6-0

Posted: Thu Jan 26, 2012 8:39 am
by John Bateson
The Lady Downstairs lived in Crawley for a few years and the friends she is staying with are avid footie fans, so last year at this time we were cheering on Crawley against Man U (who only just made it!!!).
Or it could just be Anne's antipathy towards a certain gum chewer...
John

Re: Designing & Building Great Central Locomotive Kits

Posted: Sat Jan 28, 2012 9:13 am
by John Bateson
Just received the first test etches for the next three GC locomotives, the Atlantic C4, and the B1 & B4. Chassis only at the moment but I still have quite a bit of building and validating to do, as well as testing the instructions.
Fortunately there are a lot of similarities between the three locomotives so there are many common parts but not so many that I could get away with fewer etches! One good thing is that the parts lists are almost identical and so will it be for about 80% of the instructions.

I won't post pictures here - just in case the reader spots the crucial mistake - the one that I spotted as soon as I opened the package - but I was expecting a few revisions anyway. How on earth it happened I really don't know but a couple of half etch curved lines have been rotated through 90 degrees as a mirror image for each other. Fortunately they are only guide marks for filing away the frames where the loco needs to run round small radius curves below about 1200 mm.

I'm sure I will find more as time goes by...
John

Re: Designing & Building Great Central Locomotive Kits

Posted: Wed Mar 07, 2012 8:57 am
by John Bateson
Over the past couple of months I have decided that certain myths should be dispelled.
An accepted wisdom is that the Robinson Class 8C and Class 8F, together with the Atlantic Class 8B are identical apart from the wheel configuration in the case of the Atlantic and the wheel size in the case of the Class 8F and 8C.
I guess that the boiler and smoke box with some of the chassis are similar and the chassis does not have too many changes, but they are definitely NOT the same.
I have highlighted this with the attached drawing
Body Layout.PNG
All the green bits are different from the Class 8F - there are more differences with the Class 8B

The three sets of body drawings are ready to go to the etchers now for a set of test etches and while that is happening I have three sets of chassis to build.
Happy days ...

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Wed Mar 14, 2012 7:56 pm
by John Bateson
I suppose it helps when there are similarities between loco classes, these chassis assemblies were put together in an afternoon for each one, but it helps as well if I know where all the parts fit!
B1B4C4.JPG
From left to right, Class 8C (B1), Class 8F (B4) and Class 8B (C4) main chassis - now onto the cylinders bits.

Although they look similar there are quite a few differences due to wheel size (and boiler size and pitch) and wheel arrangement.
Next will be three sets of cylinders, slide bars and crossheads - but that is for tomorrow.
John

Re: Designing & Building Great Central Locomotive Kits

Posted: Thu Mar 15, 2012 9:47 am
by iak
Mmmmmmmmmmmmm 8-)

Re: Building another Robinson 4-6-0

Posted: Fri Mar 16, 2012 11:49 am
by Horsetan
John Bateson wrote:The Lady Downstairs lived in Crawley.......



Ah..... "creepy" Crawley. :lol:

Re: Designing & Building Great Central Locomotive Kits

Posted: Sun Mar 18, 2012 11:19 am
by John Bateson
Still working on the cylinder fittings for the Class 8F, 8C and 8B. While fixing the slide bars I noticed a 'glitch' in the design and it has taken me a day to work out what had happened.
The simple fact is that for these new locomotives I mis-read the GA slightly and carefully worked it out (wrongly) that the cylinder lengths were different from the Class 8, which is of course a nonsense - with hindsight.
Its almost impossible to see the error when the test etches are assembled but I am in 'picky' mood at the moment and am modifying the etches to cover the correction - shoulda done it right first time!

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Thu Mar 22, 2012 9:32 am
by John Bateson
This morning our post lady delivered three etches for the three locomotive bodies I have under design, the Class 8F, 8B and 8C. They look alright - but we shall see!
Now I really have to get cracking!
John

Re: Designing & Building Great Central Locomotive Kits

Posted: Fri Mar 23, 2012 1:31 am
by DougN
Good luck John.... sounds like the soldering iron is going to be fired up for a few days while you work on each of the bodies! Have fun as that is what it is all about.... I just wich I could clear some time to attack the Q6 again.... as I have a LNER G5 calling for my attention from the "to do" kit box....

Re: Designing & Building Great Central Locomotive Kits

Posted: Wed Mar 28, 2012 3:54 pm
by John Bateson
Some progress made, the mechanisms are ready to be added (although the slide bars have been removed to put a self etch primer on the chassis) - but my schedule suggests I should make sure the bodies fit - and have made a start on the B1. At this stage I am ready to order the production etches for the chassis.
Soldering iron is heating up as I write.

Getting more and more tempted to see these in GCR livery ...

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Thu Apr 05, 2012 7:05 pm
by John Bateson
Still soldiering on, or should that be soldering on. The bodywork for the 8C (LNER B1) is substantially finished and just need some serious cleaning up - plus I have to define a new set of drawings for the chimneys and domes since they are shorter than those on the 'Fish' engines.

The instructions for the Class 8C are now on the web site at http://greatcentralmodels.co.uk/?page_id=27

In theory the same instructions should apply to the Class 8F (LNER B4 Immingham) excepting a few things like wheel sizes and the motion alterations that come with that.

But first, the Atlantic 8B 4-4-2 or "Jersey Lily" body must be completed and that may be a little simpler than the 8C and 8B ...

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Sat Apr 07, 2012 3:46 pm
by John Bateson
IMG_0099.JPG
A set of spring hangers for the Robinson 8 classes made from FUD acrylic - most locomotives do not have a full set but use a coil spring on the centre axle.
Coming to the conclusion that 'printed' parts are the coming thing, a couple of recent examples. For the leaf spring hangers they seem to have come out all right but I have strengthened the two rods under the leaves - which are visible only if you look hard. These replace the etch layers for the 8C, 8F and 8B, they were the traditional NiSiincluded on the Class 8 kit but are easier to fit since a 14 or 16 BA tap is less likely to break on these.
IMG_0097.JPG
These are 5 sets of the centre coil springs - the coils took a while to work out on the CAD package - but look reasonable. These would usually have been done by making masters and casting.
The coil spring hangers are simply fitted to the Markits/Brassmasters hornblocks with superglue and ride up and down with it, not prototypical but its a very tight fit under there with the valve gear. I suspect that I will add a small shelf to the hornblock mounts so that they sit behind the frames a little better.

At this sort of resolution they look quite fuzzy but at 4mm scale they don't look too bad.
John

Re: Designing & Building Great Central Locomotive Kits

Posted: Mon Apr 09, 2012 9:46 am
by John Bateson
An example of the GC Reverser - really a composite of the different types. I stopped short of adding the class type to the side of the web since I will be using these on several of the GC Robinson classes.
GCR Reversers.jpg
An approximation of the green colour, the striations of the printing process are quite visible in this picture, but probably a lot less visible when inside the cab.

I really must get somebody else to do the painting for me!!

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Mon Apr 09, 2012 10:29 am
by Will L
Just a thought John, any chance of getting them printed with the handles just off perfect dead centre?

Will

Re: Designing & Building Great Central Locomotive Kits

Posted: Mon Apr 09, 2012 11:00 am
by John Bateson
Will,
Any particular angle in mind?

I did think of a 2-part solution with the end bracket and wooden handles as the second part, but I'm not sure that will work, this second part is just a little too fiddly.
I will investigate ...

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Tue Apr 10, 2012 2:11 pm
by John Bateson
I think this latest effort may be pushing the boundaries quite a bit as far as 3D printing is concerned, but I have not been able to do this in brass.
First the original plate ...
203 Footplate Side Cover.jpg




and then the computer generated version which has passed the initial tests for uploading to the 'printers' - but we shall see what is eventually produced!
203 Footplate Side Cover.PNG

Re: Designing & Building Great Central Locomotive Kits

Posted: Tue Apr 24, 2012 1:59 pm
by John Bateson
And in the 'errata' category ...

It transpires that the steps under the cab for the Class 8 GCR 'Fish' engines are incorrectly etched - or rather they were incorrectly re-designed and then quite correctly etched. :cry:
I have had some "Spare Tender & Cab Steps" etched and may not have replaced all the faulty parts so if there are any required to correct this error then please do contact me off-list.

I am also ordering another batch of the Class 8 Fish Engines etches in the next few days to meet demand and of course the "Spare Tender & Cab Steps" should form part of the packing list...

Re: Designing & Building Great Central Locomotive Kits

Posted: Sat Apr 28, 2012 9:20 am
by John Bateson
Nealetin
Readers may recall that I use Nealetin for all my kit soldering and recommend it in the instructions for my kits.

I recently tried to source a resuppply, having bought the last pot from Alan Gibson about 10 years ago for the princely sum of £10. The price I got from the main suppliers, including carrier costs was nearer to £75.

I am therefore grateful to a visitor to Scalefour North who mentioned that Hobby Holidays near Doncaster (hobbyholidays.co.uk) resell this product at £25 plus about £3.50 for postage - and have received and tested this newer version - seems fine to me!

John

Re: Designing & Building Great Central Locomotive Kits

Posted: Mon Apr 30, 2012 1:39 pm
by John Bateson
After a hiatus dealing with things which are nothing to do with model railways, some progress on the Robinson Class 8C - not a lot remains to be done here except glue on the accroutrements and add the motor and wheels, so with the experience gained on this one means the other two (Atlantic & Immingham) should be completed a little faster.
IMG_0010.JPG

It's really quite striking considering the usual Robinson style just how much chunkier this one looks when placed up against the 'fish engines'

Time to do some cleaning up ...
John