The Bridge

Post details of your T gauge layouts and the progress you are making.
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dkightley
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Re: The Bridge

Post by dkightley »

A sort of milestone has been reached...

I've printed the first bridge component using a nozzle size of 0.2mm:
Img_2381_red.jpg
Img_2381_red.jpg (80.27 KiB) Viewed 6976 times
The section of the cross braces was getting too small to be printed using a 0.4mm nozzle, so I've had to down-size for most of the parts that are near the end of the arms.

If you look at a photo of the bridge and look closely at the side of one of the arms...there's six "crosses" down the length of the arm. The above part is the fourth "cross" if you count from the larger end.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

Reith01
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Re: The Bridge

Post by Reith01 »

I'm hardly in a position to judge 3D printing but this is beyond extraordinary. My enquiry may seem naïve but...is this near the limit?

:amazed:

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dkightley
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Re: The Bridge

Post by dkightley »

Hi Ivor

Yes, I think I'm working on the absolute limits of what's possible with FFF printers (FFF = fused filament fabrication). The part shown above will not print correctly with a 0.4mm nozzle...and is actually only just acceptable when printed with a 0.2mm nozzle.

I haunt a user forum for the slicer software I use....and there's only one other member of that forum that I know who regularly prints with such a small nozzle, but much larger parts when compared to what I do!

To get higher resolution, I'll need to jump to the realms of kit that Shapeways use.....the SLA process where UV light is used to cure liquid resin, but at the moment, such kit is outside my price range. There are one or two low cost SLA printers around....but I have no confidence in them being able to get to the resolution I would need. If I win the lottery.....well, that's a different ball game!

Meanwhile, in the real world, I think I'm on track to get printing of bridge parts done by Christmas. At a quick count......139 prints to go! And that's excluding the two truss girders that bridge the arm sections. I've not finished designing them yet as I need to assemble the arms to determine the exact length of the trusses.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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Nutter
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Re: The Bridge

Post by Nutter »

This is getting to be a fantastic build. Is the completion of printing all the parts needed going to be a forum Christmas present to all of us. ;)
Really looking forward to seeing it properly take shape.
Mike
DON'T knock it at least I am trying to do something, with only one good hand.

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dkightley
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Re: The Bridge

Post by dkightley »

My spare room is now even more resembling a building site...as the bridge structure (in dry assembled form) starts to take shape:
Lower tube sections cleaned up and fitted together:
Img_2397_red.jpg
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Two lower tubes assembled on the centre tower and (incorrectly) slotted in one of the stone towers:
Img_2394_red.jpg
Img_2394_red.jpg (116.04 KiB) Viewed 6865 times
Sorry for the bad lighting on the second shot....would have been better waiting until it got dark! Or used flash! Or drawn the curtains! :roll:
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

As spending hour after hour piddling away at bits of unwanted plastic is getting a bit repetitive....and its not doing my back any good!!! :x...and one or two other reasons I won't go into, I've decided to do a bit on the assembly of the south end of the layout.

To that end, I've glued down the remaining 50% of the layout track....the bit from the end of the bridge to Dalmeny station:
IMG_2398_red.JPG
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What I did was to cut two strips of thin ply, one on top of the other...and cut a strip of double track width out the middle of the top layer, then glued the side bits onto the lower strip, forming a shallow trough that the centre strip...the track bed...can sit loosely into. With the track superglued onto the track bed, it can be lifted out,,,because it straddles two layout sections...to allow the layout to be taken apart. Here's a close-up to illustrate this:
Img_2399_red.jpg
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btw I've found the Loctite superglue I'm using absolutely brilliant. It dispenses dead easy...and glues in seconds. Never used it much until now....and I wondering why not!

The next step is to assemble and coat the printed road sections and get them fitted to the ground surface. I'm particularly happy with the roundabout at Dalmeny:
Img_2402_red.jpg
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And just for a bit of fun, here's a Google Earth equivalent:
Img_2402_GoogleEquiv.jpg
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I've impressed myself!! :D :D
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

mattd10
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Re: The Bridge

Post by mattd10 »

Cannot wait to see a couple of HST's passing on this bridge! As well as most of the scotrail multiple units being available too! Throw in a freight or two and maybe a sleeper and this will be a truly fantastic layout!

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dkightley
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Re: The Bridge

Post by dkightley »

Had a bit of a scare this week.....

The filament I'm using for the bridge parts is Mercury Red 1.75mm PLA from http://www.faberdashery.co.uk, and on Monday I noticed that they were out of stock....something I had seen approx. 2 weeks ago.

Being somewhat concerned that they may have discontinued the colour, I emailed them asking about the availability. I got a reply back within 20 minutes apologising for the stock situation and suggesting alternate colours....so I emailed back giving details of this project and stating changing colour "was not an option". Ten minutes later, I had an email back advising they'd searched their storeroom & found one 100m roll that they could let me have...and that they would email me when stock becomes available in a couple of weeks.

A big thumbs up for Kayleigh at Faberdashery....and a weight off my mind! Particularly as I've decided to make changes to the track deck sections...and need to reprint them all!! It might cost me an extra roll of filament....but it's quite important that I can get the track to slide through some 17ft of deck sections!!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

Another landmark reached.....

I've reached the point where I have printed all of the component parts for the six cantilever arms...which now means I simply have to assemble the bulk of the bridge structure so as to determine the exact lengths of the two truss girder sections that link the three cantilevers.

I do, however, have some reprints to do - all the track deck sections. When I started cleaning the existing prints up, I found that the support material was far too well attached, making it impossible to remove without damaging the detail on the underside of the decking!! :cry: So...I have a few days printing still yet to do!

Despite the rework....I'm slightly ahead of the schedule I set myself. But I'm not going to slack.....there's a lot to do, and July's not that far away.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

Now I have Christmas over......and the staff roster site for the Tramway Museum ready to go live...I'm now able to star refocusing my efforts on The Bridge....

I have all the above mentioned reprints done....so I have just the two truss girder sections to complete - which I'm not able to progress until I get the layout boards a lot further! What I have made progress with is the assembly of the cantilever arms...or to be more accurate, the sides of the arms. Here's the first side....half glued, half loose assembled:
Img_2449_red.jpg
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Once I have this fully glued....I only have another eleven to do!

In the background is the matching side top girder and bottom tube loosely assembled into supporting parts.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

Got a matching pair of sides glued up. I have to take my hat off to the Victorian engineers - this is a VERY rigid structure!
Img_2468_red.jpg
Img_2468_red.jpg (109.02 KiB) Viewed 8218 times
And yes, that was a mince pie. :) Yum. Yum! :D
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

I've got a third of the main part of the bridge about a third assembled and glued:
IMG_2472_red.JPG
IMG_2472_red.JPG (63.97 KiB) Viewed 8193 times
I have yet to fit a set of diagonal braces between each pair of diagonal tubes, a set of diagonal braces (eight pieces per set) between each pair of bottom tubes, four small braces between the top girders, eight vertical supports for the deck, and the rail deck itself. That's why I said I'd only a third completed it!!! And the tower itself has some bits missing....

This is around a quarter of the whole length of the bridge!!! There's two more cantilever sections...and two truss girder sections to join the cantilevers together.


btw The printer its standing on is not the printer I printed the bridge with.....its my Christmas present to myself - printer number two! Bought off Ebay...second hand, approx. two years old, and never taken out of it's box!! It's like brand new!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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Nutter
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Re: The Bridge

Post by Nutter »

WOW WOW WOW that is looking superb. :mrgreen:
Now it are starting to put it all together it really shows the scale of your endevours.
Mike
DON'T knock it at least I am trying to do something, with only one good hand.

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SmallCentral
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Re: The Bridge

Post by SmallCentral »

Magnifique 8-) 8-) 8-)

martink
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Re: The Bridge

Post by martink »

It is looking really, really good. But I can't help thinking - how are you going to do the board joins? Joining the bridge sections and the track? Power feeds to the centre sections or rely on the fishplates?

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dkightley
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Re: The Bridge

Post by dkightley »

Help! :| :| :| :|

I need a bigger house! ;) ;) ;) ;)
Img_2481_red.jpg
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Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

Now I have the cantilevers at their finished length (although missing a lot of detail!), I'm starting to sort out the location of bits on the layout boards.

I've glued the viaduct sections together....one five sections long (the north) and the other ten sections long. And here's the south viaduct assembled on its piers, the bases of which slot onto blocks screwed to the boards...including the south cantilever, which just gets two of its feet onto the board section I have set up:
IMG_2499_red.JPG
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Couldn't resist a photo opportunity:
IMG_2498_red.JPG
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IMG_2496_red.JPG
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In the first of these shots you may just spot some clips at the top of each of the stone pillars. These are to aid assembly. The ten-section viaduct is in one piece, but each support pillar is loose. I assemble the viaduct upside down, using the clips to hold the peg on the top of the pillar in the hole on the underside of the joint in the viaduct. I can then turn the whole lot right side up and then slot each pillar onto its mounting block one by one....without any falling out!! The clips can then be taken out when the viaduct is stable!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

rvn2001
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Re: The Bridge

Post by rvn2001 »

This looks amazing, Doug !!!!! Will you have room in your place to put it all together? I can't wait to see it finished !!
Thom Welsch

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dkightley
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Re: The Bridge

Post by dkightley »

To answer Thom's question......

Seeing as it's a sunny day and I've just got the last three layout sections made to length and fitted the aligning dowels and board connectors. I thought I'd do a trial assembly of the layout:
IMG_2502_red.JPG
IMG_2502_red.JPG (68.73 KiB) Viewed 8071 times
And they actually fit together very well...and track a surprisingly straight line considering each 1 metre section across the front and back have been cut to length by hand!

The mounting for the north end stone tower can be seen in front of the second concrete fencepost from the left, and the mounting for the south tower is just to the right of two fence posts further along in front of the gate.

This might just be the first and last time the whole set of eight layout sections are together before it travels to it's first show!!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridge

Post by dkightley »

The last few days have been...to say the least....have been so, so boring! and things won't improve for a few days yet!!

I'm in the middle of cleaning up the 3D printed parts that have yet to be assembles on to the cantilever arms...which means there's six of everything! Here's the parts already cleaned:
Img_2507_red.jpg
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Here's what left to do:
Img_2509_red.jpg
Img_2509_red.jpg (90.84 KiB) Viewed 8038 times
And here's a close-up of one in the queue showing typically the amount of support and flash I'm having to remove:
Img_2511_red.jpg
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Note that this amount of rubbish removal is not typical for 3D printing....it's because the parts are very complex girder structures and the printer is having to make hundreds of moves to make very short extrusions, and I have had to set the printer to a compromise between reducing ooze/stringing and having sufficient extrusion there to ensure the nozzle doesn't stop extruding and jam!

On a much brighter note.....or should it be a scarier note....I've now received the official invitation to take The Bridge to the GCR Model Event in June. So it's full steam ahead......
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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