Atlantic's works: Portable layout - Scenic details next

[jwealleans]

As opposed to a twitch?

Can you conceive of a twitch ever being other than thoroughly Imperial?

Or should that be imperious.....?

[Atlantic 3279]

A twitch is very obviously imperiously imperial, and would no doubt be purple if it were able to assume a colour.

I only "twigged" that the glazing could be snapped into its marked sections after examining the lines on it for a while, wondering how they had been created, feeling them with a finger nail and initially concluding that they were raised lines, then feeling more carefully and realizing that they were fine grooves with a fine raised line of displaced plastic either side of the groove. I was too cautious or cowardly to try snapping along the lines straight away, initially feeling for the groove with a blade and running the blade around just one piece which I wanted to use to test the fit. Having thus probably deepened the grooves in that one area I flexed the plastic to see if it would break cleanly, and noted that it seemed equally happy to continue to break along the whole length of those score lines that I had only partly deepened. I then tried one of the score lines that I had not touched at all with the knife, and found that the plastic snapped cleanly along that line too.

[Atlantic 3279]

Or a gnats?

Always liked A5s. Big beast of a tank engine that just look strong and fit for purpose.

I quite agree Morgan, when the A5 is seen in isolation, but against Robinson's L1 introduced only three years after the A5 Coronation Tank, the latter looks a bit under-nourished....

In view of the experiences of other with Bill Bedford's clip-in GNR carriage roofs, I don't like the idea of having the carriage body permanently glued to the underframe and the roof potentially impossible to remove without damage. I am therefore trying out an idea for fixing the body to the "keen to bend" underframe firmly enough to keep the underframe straight, using just plain pins that can be slid out again if necessary. Pictures will have to wait until tomorrow. Ashes to Ashes beckons and Gene Hunt doesn't like to be kept waiting!

[Woodcock29]

In regard to the Bill Bedford resin coaches I can now see how it could be possible to insert pins from the ends that would be be basically invisible and could be manipulated with tweezers inside the underframe - they would go into the back of the seat bases on the underframe?

I briefly tried to figure out if I could screw the underframes to the body somehow but didn't spend long thinking about it!

As well as the stripped A5 I've also got a partly stripped L1 'Crab' and it is huge in comparison. So far I've stripped the chassis which was glued together. It'll probably be fitted with a large Portescap I have spare when I get around to rebuilding it.

Andrew

[Atlantic 3279]

Which are the other two you got?

Andrew

I forgot to answer this regarding the GN 6 wheelers. As well as the D.245 third I have the D.154 composite and the D.303 full brake. At least that means there are three ends that can simply be screwed to the underframe if I just build hidden plastic blocks to recieve the screw inside the ends of the brake / luggage compartment.

[Atlantic 3279]

I've done almost what Andrew suggest above regarding the removable pins in the carriage ends, linking the body and underframe, but because the upright backs of the seats are printed as parts of the body rather than the underframe, there wasn't much of a target to hit if I simply tried to drill into the lower seat structure, working blind, from the outside of the body. I didn't want to miss completely, or end up with only half a hole in the edge of the seat frame, or hit bull's eye but weaken the seat frame so that it tended to split. What I chose to do was to stick together three layers of 0.75mm plastic and super-glue these into the opening behind the seat base at each end of the carriage:

As the underframe was hump-backed, the pull on the 0.9mm pins when the carriage is assembled presses the super-glued joint together, rather than pulling it apart, so I hope there's no reason for it to fail, and there's plenty of depth to the plastic beam under that seat to resist the pull. The seat ends haven't been touched, so I hope they are strong enough to continue to bear the little bit of tension.

When the outer ends of the pins are filed flat and pushed fully home the carriage end should look normal (and will probably be dirty black anyway) and even once the buffer tails are in place there should still be access from below the open-bottomed seat to push the pins back out if necessary.

Pushed in, the pins certainly do the job of pulling the frame ends up straight under the body:

[Atlantic 3279]

A metal strip or tongue, filed up to width from some nickel-silver etch waste, pushed (with suitable care) in and out of the tight glazing slots has worked very effectively as a means of opening them all out to the correct width for the un-trimmed pieces obtained from the snap-to-size glazing sheet. Nothing has snapped or otherwise gone wrong in the process. I made three sizes in the end, third class quarterlight, first class ditto, and door. Much quicker I think than filing the edges of dozens of pieces of clear plastic. The only real tight spots almost all turned out to be within the cantrail portions of the sides. Picture to follow, but my camera is being naughty at present......

[Atlantic 3279]

For no particularly convincing reason, the camera now works again......

[Atlantic 3279]

Not a huge amount of further progress on that carriage today. I hope I've removed the remaining supports and pips from the print. I also decided to do something about a problem with the shape that I had belatedly noticed - not something abut which I have any real complaint as I accept that this sort of 3D printing is still in the realms of "new and developing technology" with no certainty of long term stability and durability. Anyway, what I had noticed was that both sides and the end of the upper half of one of the end compartments were leaning slightly towards the opposite end of the body. Top and bottom edges were straight enough, so it was a shear rather than bend in the structure. What I've done to reduce the problem is to cut through the cantrail at each side above the corner of one of the quarterlights using a razor saw, insetrt a slip of plasticard to slightly lengthen the cantrail and super-glue it in place. I believe the result is better than it originally was, although not perfect to the most intense scrutiny. Whether it was bad enough in the first place for typical observation to detect it is another question.....

[Atlantic 3279]

Here are the inserts I've used to extend the cantrails and straighten up the end compartment window frames and the carriage end itself.

I've also had both the body and the underframe briefly in very hot water (which softens the structure very markedly - beware) so that I could remove a slight twist before fitting wheels, cooling the parts again under the cold tap once straight.

I now have to confess to having a bit of an "emotional" moment last night, brought about my attempts, in all ignorance, to fit wheelsets, Bill's suspension system, and parallel-sided "flanged" 2mm pin-point bearings into the spaces between the axleboxes on this coach. Fortunately the emotional moment only included violent language.

After consulting "one of our readers" I have now been enlightened on the use of waisted pin-point bearings, and I'll be obtaining some at the first convenient opportunity. Also, in calmer mood this morning, I experimented cautiously and found that there was enough substance in the axleboxes for me to be able to open out the elongated holes to accept the fatter ends of my bearings, also finding that I had to slightly deepen the bearing holes for the centre wheelset. I now have all wheels installed, spinning freely, centre axle translating freely, with all springing working freely too. Brake gear next I imagine...

[Atlantic 3279]

Brake gear indeed. I like the way that the brake gear for each wheel set comes in two halves, each one a pair of shoes and a yoke, all on a sturdy baseplate that only needs to be stuck to the underside of the floor. Each baseplate has a half-oval cut-out in one edge that looks as if it ought to fit tight against one half of a raised oval on the floor, but that would clamp the brake shoes tightly onto the wheels, so care with positioning is needed. The brake gear all seems to be to "full gauge" too, no allowance for putting shoes in line with OO wheels, but I'm not complaining, as the brake gauge is correct.

One thing I'm not sure of though. The centre-line of all of the brake shoes and the plane of all of the yokes lies about 2mm above the plane of the axles if the brake sets are fitted as supplied. I'm not sure that looks right as the brake shoes appear set to try to clasp the wheels well above the level of the axles. Have others found the same, or made any alteration?

[MikeTrice]

You should probably be using Mansell Wheels for the 6 wheelers.

[Atlantic 3279]

I agree, without reservation. I'm afraid I'm using what I already have, and have had in stock for many years, acquired on favourable terms.

Behind the w-irons, springs, and step-boards, weathered and rotating, I hope that my cost-cutting will not be noticed by too many observers.

[Woodcock29]

Graeme
I did indeed need to space the brakes on mine with ~ 40 thou styrene sheet - this brought the centre of the brake shoes to just below the bottom of the lower steps. I also managed to break the end off one of the steps but it was easily fixed and reinforced with wire behind it it in epoxy, after I finished all the work on the model.

One of my kits had two complete sets of brakes - one narrow and one wide so catered for all gauges. In the other, three of the print modules were wide and only one was narrow so I needed to use two wide units, which I narrowed by cutting them up and just using the actual brakes with a rod between them rather than the yokes. I actually did this to the narrow ones on this vehicle as well so they were all the same - you can't really see them anyway.

As for the the axle boxes, on the first one I did what you did as I thought I only had standard flanged bearings then having drilled them out and elongated them vertically I remembered I had some waisted bearings bought last year from a deceased estate! I think I kept the standard bearings in use on the centre axle of that coach, remembering that my other kit had these centre axle parts missing so I concocted a centre axle suspension unit with spare D&S parts - both seem to work equally well. On Bills axle suspension units I found I needed to run a file down the outer edges of the sliding part to ensure they moved freely.

On my previous printed bogie Dia 129 half the brakes were narrow and the other half were wide! I should have had a full set of both.

Andrew

[Hatfield Shed]

You should probably be using Mansell Wheels for the 6 wheelers.

A printed insert to fit in the recess of the wheel face would be a simple production.

Have Mansell centred wheels been produced for OO since the neat MGW product of the 1970s?