Atlantic's works: Portable layout - Scenic details next

[Horsetan]

That expansion link and hanger bracket assembly looks lovely.

I was wondering if more expansion link layers could be provided in case P4 people want to have a go at full "box" links and forked joints

[davidwest]

Edward Thompson did himself no favours by rebuilding Great Northern. But you've made a top notch model very accessable.

[2002EarlMarischal]

Welcome back Great Northern!

Quality work as always and a great result on the etches clearly worthy of the time and effort. Congratulations both Graeme and Morgan.

Following your note in classifieds Graeme, please can we have an update on availability of the resin and etched parts?

[Atlantic 3279]

Thanks for the comments.

Regarding a multi-layer expansion link: The single layer version came about because, whilst Comet offered the option on the original etches that I used for the A2/3, and I initially fancied building the valve gear that way too, the more I had to "play around" with alterations to rod lengths as I built up that prototype Thompson Pacific conversion the more it seemed to make sense to keep things easy and simple. The A2/3 looked okay when finished with a single layer link, so I never took matters any further than that. I agree that on critical examination the multi-layer links look far more realistic, and of course Bachmann provide them on their latest generation locos. Hornby tend not to bother. IF we do a re-design of the etches, I'll put the question about multi-layer expasion links to the CAD Meister himself. He can then decide whether he wants to do the work. I'll quite understand if he'd prefer to alter as little as possible, as he had a torrid time with the artwork for this first set of etches owing to repeated conflict between his file formats and the etchers' versions of those (apparently) same formats!

I will update fully on resin part availability soon. In principle there is no problem. The moulds are all useable now just as they are, although I may be tempted to make a revised version of the mould for the side running plate pieces. Finding time to do the casting may be a problem before early to mid July, as there are a number of family and professional matters that I need to deal with first.

[45609]

There is not much more I can add to Graeme's comments for the time being. We will be getting our thoughts together on what we might like to change for a production etch shortly. All comments that have been made will be considered. After that we will announce pricing details for each etch.

I don't anticipate anymore issues with CAD file interchange as I now know what the etcher needs and can work with. In management speak, I've ascended the learning curve.

Cheers....Morgan

[jwealleans]

Looks like you've leveraged that paradigm and got all your ducks firmly in a row. Now just keep pushing at that envelope.....

[45609]

Jonathan....naughty step, five minutes ------>

[jwealleans]

That's what three weeks working with Americans does for you. At least I didn't whoop.....

[Atlantic 3279]

SINCE THESE NOTES WERE ORIGINALLY PRODUCED, A SEPARATE AND FULLY COMPREHENSIVE SET OF ILLUSTRATED INSTRUCTIONS HAS BEEN PREPARED AND IS AVAILABLE FROM ME BY E-MAIL. IN ORDER TO USE SPACE TO BEST EFFECT THE IMAGES ORIGINALLY DISPLAYED HERE (AND LATER LOST DUE TO DISCONTINUATION OF REMOTE-HOSTING SERVICES) HAVE NOT BEEN REINSTATED

Here's how an A2/1 version of the motion bracket would go together. It uses the fold-up "core" bracket, rectangular front panels and side overlays that are all unique to this version, so you need to identify these and make sure you don't get muddled up with loosely similar parts for the A2/2 & A2/3 versions. Unless you are stupid, and rushing rather blindly as I was, you'll drill the half etched holes of choice in the add-on inner motion brackets BEFORE you assemble the whole lot......


You have to drill the OTHER pair of holes (the front one in each pair) if building the A2/2 or A2/3 version.
With side overlays added and the leading edge rounded by filing this is the result:

If you remember far enough back, you'll realise that the rear of the original Bachmann A2 outer slotted slidebar solders onto the tab that is turned forwards at the rear of the plain inner slide bar shown above. That allows you to retain the Bachmann crossheads and cylinders, and provides extra clearance behind the slidebars for the leading crankpin that would not be available if the thick plastic Bachmann inner bar were retained.

[Atlantic 3279]

SINCE THESE NOTES WERE ORIGINALLY PRODUCED, A SEPARATE AND FULLY COMPREHENSIVE SET OF ILLUSTRATED INSTRUCTIONS HAS BEEN PREPARED AND IS AVAILABLE FROM ME BY E-MAIL. IN ORDER TO USE SPACE TO BEST EFFECT THE IMAGES ORIGINALLY DISPLAYED HERE (AND LATER LOST DUE TO DISCONTINUATION OF REMOTE-HOSTING SERVICES) HAVE NOT BEEN REINSTATED

Here's a start on an A2/3 motion bracket. Note that there's no front panel to fit in this case. The A2/2 version is the same, save for the final side overlays which are the ones with raised edges, rather than the plain version waiting to be fitted in the images below.


By the way, I've done nothing with these A2 brackets so far to provide the necessary electrical break between the two sides, but the stretchers can be seen to include guide lines for a choice of cutting positions, allowing you to split the metal stretcher and bond the pieces onto an insulating sub layer.

I'll try to continue later. Must return to earning a living now.....

[Horsetan]

Looks like you've leveraged that paradigm and got all your ducks firmly in a row. Now just keep pushing at that envelope.....

It's "cocks on the block" time! JFDI!

[Atlantic 3279]

SINCE THESE NOTES WERE ORIGINALLY PRODUCED, A SEPARATE AND FULLY COMPREHENSIVE SET OF ILLUSTRATED INSTRUCTIONS HAS BEEN PREPARED AND IS AVAILABLE FROM ME BY E-MAIL. IN ORDER TO USE SPACE TO BEST EFFECT THE IMAGES ORIGINALLY DISPLAYED HERE (AND LATER LOST DUE TO DISCONTINUATION OF REMOTE-HOSTING SERVICES) HAVE NOT BEEN REINSTATED

With a basic A2 variant motion bracket structure completed as above, it's time to add the radius rod, lifting lever, and expansion link. The final position of one of the joints within the structure already completed means that the nose of the lifting lever must be pinned into the slot in the rear of the expansion lever, and the excess pin length trimmed off, before the two joined components go anywhere near the motion bracket. See the inset picture below. I may have actually got this bit slightly wrong, now that I've looked again prototype photos and have tried the assembly against my finished loco. Firstly, the lever perhaps ought to go OUTSIDE the radius rod, not behind it, and either way, any pin that remains on the outside face of the joint needs to be flattened down as much as possible. A full domed pin head left in place is a nuisance.
These tow joined components then have to go into the bracket, with the expansion link outside them, plus a paper spacer outside of that, and a pin has to be put through from within, through the inner motion bracket, *the middle eye of the lifting lever, the pivot point of the expansion link, a paper spacer, and finally the outer bracket. A second pin from outside needs to go through the heel of the lifting lever into the inner bracket. The picture should clarify this! These pins need to be soldered up, with the lifting lever pushed as far outboard as it will go. Then trim those pins but don't remove the paper washer yet.

(There may be a good case for also passing this pin through the rear of the slot in the radius rod - it makes the position of that rod almost fixed solid, which isn't so good if you find that the radius rod doesn't meet up nicely with the top of Bachmann's combination lever, but providing that it fits it does tend to put the joint with the combination lever in a more authentic position).
The chosen overlay then goes on the outrer face of the bracket. If its is the A2/2 or A2/3 type, the bottom of the overlay piece must turn under the base of the motion bracket to complete the rounded lower corner. The paper washer can now be pulled out and the eccentric rod can now be pinned onto the inner face of the foot of the expansion link.

[Atlantic 3279]

I'm not fitting this set to a loco yet, but everything suggests that it WILL all fit as per my original A2/3 method with the modified Comet valve gear.

Con-rod parts - the big end holes fit the Bachmann crankpins nicely too!




Length is perfect compared to my previous Comet adaptation

The nice small holes in the little-ends of these con-rods should ensure that it is feasible to introduce the new little end pin from the outside face of the drilled crosshead, then solder on the inside face of the rod and crop off the excess. There should be no need to use the head of the pin to partly fill an over-size hole in the con-rod. This avoids any need to contemplate either soldering a retaining washer on the visible end of the pin, or locking the pin in the crosshead with loctite or similar. The drilled hole for the pin in the crossshead will of course have to be large enough to result in a loose fit.

Although this is blurred, the eccentric rods when laid over the shortened Comet ones are just short enough to miss the rears of the slidebars too:


When the whole asembly is placed upside down on Steady Aim's chassis, with stretcher position matched to that of my modified Comet valve gear, everything falls into the right places.

[Atlantic 3279]

The new A2/3 and A2/1 smoke deflectors correctly match the shape of the resin running plate top, which is a bit of a relief:

[S.A.C. Martin]

All looks utterly superb. You have both done a grand job on the etches.