West End Workbench

[earlswood nob]

Good morning all

Looking good, JW, and like many postings on here, makes me want to build my spare Atlantic. However, I must keep my nose to the grindstone with the 0-6-0's.

AGW does some small 2mm bearings (4M65S) which I find useful for bushing tender frames.

Earlswood nob

[drmditch]

Please excuse an 'ignorant' request.
Could you send me details for AGW, because I don't think I've heard of them before.

[jwealleans]

Morning David,

AGW=Alan Gibson Workshop.

[drmditch]

Of course!
Many thanks.

[Dave]

Glad you asked that (AGW) had me foxed...dow!.

Looking good Jonathan, you make it all look so easy.

[Pebbles]

The DJH C1 and C2 both have quite significant dimensional issues. One manifestation is the deep tender frames resulting in a deeper buffer beam to keep the buffer high at an acceptable level.

[Woodcock29]

My understanding of the dimensional issues with the DJH C1 and C2 is that the engines themselves are actually made to 4.25mm scale as a consequence of an accidental scaling up of the whole loco from the lengthened driving wheelbase that was necessary when the design work for the first kit was being developed. Can't remember where I read this. Can anyone confirm this?

When I built my C2 I shortened and narrowed the footplate to make it the right length - this probably introduced other errors?

I have deliberately not built the DJH C1 kit I have because of the significantly oversize boiler/smokebox.

Woodcock29

[earlswood nob]

Good morning all

Very interesting, Woodcock, as I've often thought that the DJH Atlantics' wheelbase looked too long.

I didn't for one moment think the whole loco could be overscale.

Earlswood nob

[LNER4479]

Yikes - a C1 on steroids. Is Grantham's station footbridge safe, I ask myself...

[Atlantic 3279]

Time I put my model against the Isinglass drawing I think.....

[jwealleans]

Once you've done that, try doing it again over a barrier and 3' away from the loco (which can be moving). If it looks like a duck.....

Not that I endorse wilful inaccuracy in any way, but Graeme's DJH C1 is as good looking a model of one as I've seen and doesn't shout 'wrong' when you see it on the layout.

[earlswood nob]

G'day all

I've always thought the gap between the driving wheels looked too large, but the loco always looked OK.

I wrongly assumed that DJH, like GEM with the D21, made the wheelbase too long.

I only discovered that the D21 wheelbase was too long, when I made a scale length chassis. Then a modeller on here informed me that it was 2mm too long over the splashers.

Like the majority of modellers on here, I've been bitten by the bug of trying to get a model as accurate as possible, to the limits of my modest ability. However, as JW asks; how many can see the inaccuracies at a distance of three feet?

Earlswood nob

[jwealleans]

Just a little progress last night - i didn't think anyone would want pictures pf paint drying.

I put the WSM chassis together last night. The wires will need rerouting once the flywheel is fitted - I have a friend turning the bore out to 2mm at the moment as i had acquired a number with 1.5mm holes. The gearbox is a RoadRunner Plus with the pivoting section loctited in the vertical position.



The pony wheels on this kit were the right size - you can see how much smaller the AGW bogie wheels are to clear the front end.

[Woodcock29]

Hi Graeme

I have the Isinglass drawing and have just measured some of the kit parts against the drawing. The footplate is 4.5mm too long and 1.5mm too wide. The smokebox is about right, the firebox is 1.5mm too short and the boiler is 2.5mm too long meaning overall it is about 1 mm too long - okay so that's not too bad. However the boiler is also about 1.2mm too big in diameter and that is probably the one dimension that makes it look too big when compared to a pacific such as a Gresley A1. Interestingly the cab is about right.

The driving wheel base measures about 28.7mm and was always going to have to be too long to accommodate model flanges if the driving wheel diameter is about correct, compared to 27.3mm (6'10") on the prototype.

In getting out the Isinglass drawing I have found the source of the comment that it is built to 4.25mm scale. The late John Edgson said in his covering letter with his Isinglass drawing, dated 22/10/2003 said: "I know your problem with the DJH Atlantic Kits and this has caused much anger within LNER modellers. What happened is that they contracted out to a well known professional modeller the making of the masters, giving him my drawings. As the kit was to take 26mm Romford drivers at 4mm scale the 6'10" centres were too tight. He then decided what was the minimum centres that could be used and found out what the scale size was. He then built the kit to this scale, ie 4.25mm to the foot. This might be alright as a display model, but he forgot that the structure gauges of a layout of 4mm would infringe upon the resultant engine."

I haven't done the calcs to see how close it is to 4.25mm scale but it seems to me that there are significant inconsistencies to the scale to which the kit is actually made. There have also been comments in this thread about the tender height, although my C2 doesn't appear to be significantly to high at buffer level.

To me the overscale is not so obvious on the C2 if the footplate is shortened and narrowed, although the cylinders will then stick out a bit far but I can live with that.

It will be really interesting to see how the Bachmann/NRM C1 looks when it arrives compared to my DJH kit of parts. I was intending to sell the DJH kit if I can but I might keep it. Markets for such kits here in Australia are few and far between and I'm not sure I can be bothered selling it on eBay. Possibly the boiler can be narrowed by slotting it and the smokebox along the bottom and squeezing them in a bit. I wish I hadn't dismantled my old Ks C1 as I think that was about right in size even if a bit crude - I eventually plan to rebuild that as your namesake in late 1930s guise - but I have probably told you that on one of my visits. I have been collecting valve gear parts for that from a range of kit sources.

Regards

Woodcock29

[Atlantic 3279]

While you were typing that I was typing this.

Yes, from reasonable viewing range the DJH loco convinces me at any rate. As has been alluded to previously in specific connection with the tender, there is significant distortion of dimensions below the running plate, possibly for the sake of wheel clearances (and we all want the locos to run properly rather than just look nice), possibly also in line with (or for compatibility with) the prevailing RTR tendency of former years for having running plates and buffers too high. I reckon my loco and tender sit about 1.5 mm too high at running plate level. Before we whine too much about that, I think we ought to take a seriously hard look at Hornby's current "marvellous" LNER Pacifics which I'm sure are STILL slightly too tall if we're getting pedantic. Also, DJH have extended the front of the Atlantic running plate by something like an extra 2mm ahead of the smokebox front, but at least that gives the bogie wheels somewhere to go when running around model railway curves.

Below are other figures, listed as: my built-up DJH model, then scale, then % enlargement:

Coupled wheelbase: 28.5 / 27.3 / 4.4%
Total loco WB : 109 / 105.4 / 3.4%
Running plate length 138 / 133 / 3.8%
Cab height 32 / 31.5 / 1.5%
Smk box front to cab 109.5/ 108 / 1.4%
Clad boiler diam. 23.2 / 23.2 / spot-on!
Smk box diam. 25 / 24 / 4% (pity about that, I should have had my big file out....)

It doesn't appear to me that there is any "consistent" increased scale to which the model was designed, and certainly not one of as much as 4.25mm:1 foot which would be 6.25% too large. Although the height to running plate is around 8.5% too much, the total height is less than 4% too great. Although DJH deserve no credit for their suggested arrangement for the rear carrying axle's suspension, I think they made a pretty fair job of designing a loco that could be built, would still look convincing and would actually work with the wheels on offer to most at the time.