Shapeways quoted an early June delivery, unless I paid a whole load more for a 'rush/priority' service. They wanted about $250 to reduce the delivery time to about a week. 250$? That's taking the P. I'm impatient, but not $250 impatient! As it turned out the 'early June delivery' dropped through the letterbox yesterday, with the bog standard priority and lowest cost shipment. Ironic? Cynical? Anyway...the parts.
They're printed in a translucent acrylic plastic and it's claimed that the process will resolve detail down to 0.1mm. I also opted to pay a premium for the smoothest surface finish option, just to see what was possible. This is what I got....
They looked pretty good out of the box. It's hard to show the detail in photos of translucent stuff, but even the smallest CAD details were present and well resolved. I'd chosen to keep the feature size to no smaller than about 0.2mm on CAD, but from the looks of this you could probably model detail right down to 0.1mm if you wished. There's still some visible layering with the 'smoothest' print option, and on parts like this there's no practical way of hand finishing to remove it. On larger, more accessible surfaces you could rub off the layering quite easily. The material files and sands nicely. I added some temporary diagonal bracing to support the hanger rods during manufacturing and handling. They're positioned so that they're easy to remove, and the scars don't show. The back of the box is hollowed out just to save material (the cost is partly determined by the volume of material) . There's a circular spigot on the base of the spring that pushes into the hole in the top of the axle box. Both modelled dead to size, and they're a light push fit. So the dimensional accuracy's good as well.
This is about as close as I can take a photo, and you can see the layering. The orientation of the layering depends on the orientation in which it was printed. I didn't specify that, it's done by the Shapeways folk when they prepare models for printing. This particular material and process uses a wax support matrix, so the design isn't so constrained as the 'build into thin air' process that a lot of 3D printers offer. Interestingly the springs were printed in a couple of different orientations, so the layering runs in different directions. You can tell if you look closely enough, but at model viewing differences I'm guessing it's invisible. We'll see.
It's recommended that you wash them in acetone before painting to remove any remaining trace of the support wax and uncured resin. Here's one with a coat of grey acrylic primer. Applied by brush in this instance, but I'll spray the rest along with the tender when it gets painted. You can still make out the layering, but it's not apparent at model viewing distances. Captures the look of the Stanier axle box very well, I think.
One of the cast white metal axle boxes with the same primer for comparison. They're not bad for overall size and proportion, but you can see that the crispness and fine detail gets lost at this size, and there are features of the prototype that I think would be impossible to replicate in a casting pattern by traditional means (somebody on WT is going to prove me wrong, you can guarantee it).
Was it worth it? In terms of what it brings to the model, yes, definitely. And a decent return for two days of research and CAD. In terms of money spent, not really. I'm not going to disclose what the exercise cost (I'm still working out the domestic forgiveness strategy). Technically it's viable and the results are brilliant, but I'd have to find a more cost effective way of getting them printed, and maybe experiment with materials and print resolution to get the cost down.
The cat's well and truly out of the bag after the stable door was bolted, and I can't help wondering how 3D printed number and works plates would turn out. Particularly since the Severn Mill chap is stood down at the moment. Hmmm...
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In other news, I've finally got around to making the DCC stuff work for the first time.
Ok, it's not in a loco, but after updating software and getting the bits to communicate, the motor responds as expected and the speaker makes noises. I've not set up the key press functions properly yet, so there was certain amount of pressing virtual buttons to see what happened. For a frustrating period there was motor but no sound, until the house was awoken by a surprisingly loud 8F whistle when I discovered the un-mute button. Next job is to work out how to wire it all up in the loco and tender. DCC duck broken, and I can see this has a huge amount of tinkering potential.
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This is the dangerous distraction that I unearthed from a box when I was looking for something else.
A 4mm Impetus kit for the 15" Hunslet. I got it from a Scalefour Soc 'for sale' ad a couple of years ago. Original and untouched, it's a rare thing these days. There are Gibson wheel sets, what looks like a High Level gearbox, Mashima 1020 motor, Kean Maygib buffers, and a load of High Level CSB jigs and parts. The kit is very nicely done, but oh so retro! Typewritten and copied instructions and hand drawn assembly diagram. Life was simpler then. Looks like it'll make a nice little engine (somewhere between Percy and Thomas in the Fat Controller scheme of things). Can you get DCC and sound in something this size, I wonder? Like I said, dangerous distraction - I really ought to finish a project sometime, before starting another.
