I've gotten my first prints back from Shapeways. I'm generally satisfied with everything, but I will need to make some adjustments to the parts to account for robustness and ease of assembly before I print other copies. Let's see some pictures.
There are four components in the radiator fan assembly. Shutters, fan blade, plenum, and backing piece with mounting pin and motor stand "legs" in relief. I printed the shutters and fan blade together, and the plenum and backing together, to save half on the $5.00 per part handling fee. The first pictures show the parts as printed, connected by sprues.
Now separated, with the aid of some flush cutting sprue nippers. First is the shutter assembly, with vanes and mounting flanges. I've already broken off the first vane, without even trying.
Hopefully some CA will make it right again.
Next are the blade, plenum (already inserted, I couldn't help myself
) and backing piece. The plenum is the circular insert with the gaps at the four corners.
And mocked into the nose of the shell. I've kept the shutters separate for now for fear of breaking them all.
Final result will be something like this.
The tabs on the rear of the shutter assembly are supposed to slide into the gaps at the corners of the plenum piece, but the fit is too snug at the moment. Taking a file to the parts, especially the shutter assembly, will possibly damage them. I'll give it a try, but I have low expectations. I can always glue, and I know I will be printing at least another copy or two in the near future.
The full assembly of four parts can be screwed together by tapping the holes located in each corner. This is so parts can be disassembled if needed for painting or weathering. Once assembled, the whole thing will fit into the radiator opening as shown in the last picture. A new etched metal grill will cover it all, but that's another project. I mentioned in my last post about the possibility of making the shutters able to rotate. That may require a hybrid approach, with a wire pin at top and bottom to replace the printed nub that connects the vanes to the flanges. I don't think the plastic can handle the movement. But again, I'll cross that bridge when I come to it.
I printed some other parts at the same time. One is a set of replacement gear box covers for the Atlas sw8/9 switcher trucks that I will be using. The originals show a tendency to tear out at the corners where the attachment screws are located. The OEM screws are flat heads, countersunk into the cover. I presume that overzealous tightening of the screws puts some lateral force on the plastic, which splits it out. Countersinking the hole also removes quite a bit of material so that may contribute to the problem as well.
These covers are printed in the flexible plastic material instead of the Frosted Extreme Detail used for the radiator parts. I wasn't concerned with the finish aesthetic as the part won't be seen. As can be seen indicated on the cover, these covers are intended for a P48 application, with the side frame mounting tabs and corresponding holes moved significantly closer to the centerline of the truck. This relocation will bring the brake rigging over the center of the wheel tread. The side frames are designed to accommodate the 3-rail market with its huge wheels, so the brakes hang out over nothing when wheelsets are substituted.
3-Rail versus P48 (.115" tread width plus 4'-8 1/2" gauge)
3-Rail versus 2-rail (.145" tread width and 5'-0" gauge)
These are in the works in brass and in regular 5'-0" gauge 2-rail as well, but I got impatient and had some printed. The material is a bit too flexible where the side frames attach. Brass will be better. These are also designed with pan head screws instead of the countersunk flat heads so that the only stress on the plastic is the clamping pressure. The brass versions are countersunk, and can utilize the original screws.
Last up are some rungs for end and side ladders for my long dormant TBOX project. This was largely a test to see what was possible with the Frosted Extreme Detail material. They look decent, even though you'll have to take my word for it. My phone can't manage anything better for photos. For scale reference, the fan blade is 1 1/8" diameter across opposite blade tips. The rungs are drawn at a scale 3/4" diameter. They are modeled to have the proper forged shape at the ends and include the rivet detail on front and back. With my visor, I can just make out the shapes at the ends of the rungs.
They will theoretically attach to etched metal stiles to form the ladders. I may explore having them cast in brass for strength, considering what I've already learned with the shutters. Either way, I'll need some stronger magnification to work with them.
Currently in the queue is a bunch of cad work. I need to finalize etch for the front and top grills, work up a model for the radiator core, and I'm currently working on a 3d model of the flexicoil trucks used on the sw1500's.
Even with the modified gear box covers that realign the brake shoes, there is still a tremendous gap between the wheel face and back of sideframe due to the tread widths. The sideframe itself is too thin, again to accommodate the 3-rail wheels. I was going to back it with some styrene and file to match. But as I got to looking at the Atlas sideframes, I concluded that they are rather poorly rendered compared to the prototype. The general form is there, but the details are wrong. So of course I'm going to model some of my own, and either have them printed for direct use, or printed to use as masters to cast.
I've just stumbled on a resource for EMD loco data the other night that is pure gold for technical information and technical drawings of components including essentially every EMD truck style including Blombergs and HTC-1's. I'm talking about plans, sections, elevations, and break-outs for brake system rigging, in pdf format that can be inserted into cad, scaled, and traced. I've been looking for data on the HTC trucks for years, in fact it's how I ended up here in the first place, with a mention in Mick's US modeling thread.
RR-Fallenflags.org
Fallen Flags locomotive manuals page
Go the EMD master parts catalogs on the Manuals page and get lost for a while. It's mind blowing how much information is available there. There's also material for other loco manufacturers as well. But right now all I have time to worry about is EMD. Be forewarned though...it's a
deep rabbit hole.
Here's a sample for the EMD Flexicoil 2 axle truck I'm working on now.
That's all I've got for now. Hopefully that's enough!
I have family business to deal with through the end of the weekend, so little is likely to happen between then and now. But I will have my laptop with me, and source files, and can work on cad if I have free time.
Cheers,
Jim