This is my most ambitious print job ever. It takes up almost my whole build platform and will take an estimated 20 hours to complete. It is the front end of my coach 64 with windows and door casment as well as bead board and trim. I've already had to abort this print job three times. Once the machine stopped printing and I discovered that the ribbon cable to the extruder head had popped off. The next time I discovered the extruder got impacted when the job shut down. The last time, I started the project only to discover that the bed needed leveling. Luckily the last two times I aborted I only lost a total of 3 hours. I started the project early this morning and it seems to be moving along much better than the previous three attempts. While I wait for the front wall to print, I work on the air brakes. I have another pair of 1:20.32 scale brakes, but this is a 7/8ths scale project so I decided to build a 3D model of the brakes in 7/8ths scale. Not bad for some sketchy dimensions and blurry photos being the only resources I have at my disposal. I also printed out all the windows and window casements for the lower part of the coach along with 3 out of 8 siding panels. I'm getting closer to assembly.
Well, it took a total of 14 hours to print not including the windows which I already printed. Now, I have to print the rear end.
After printing out the front end wall, I went back into the model and redesigned both the rear and front end walls. The improvements reduced the print times by four hours. I didn't realize till I owned my own printer just how hard it is to slice and print an model built by combining several shapes instead of a single mesh. As I waited for the print to finish, I worked on the brakes for the coach. Coach 64 has an interesting brake configuration. As you can see the triple valve is connected right to the brake cylinder instead of the resevoir which requires a mounting plate I could not find in any plans online. I did my best to copy the dimensions then, Then I converted the 6 parts I wanted to print to solid meshes in meshmixer and added the lettering. The lettering didn't slice well so, I doubt it will print, but it is worth a try. I will run it at 20 micron layers with 20 microns being the minimum detail and see if that get's close.
The lettering printed out just fine (both times). I had to rescale the first print after I discovered it was too small for 7/8ths. The image above is of the revised print. Here is an image of both sizes. I switched back to hatbox filament. The monoprice filament had issues with flowing. Of course, after switching reels, there were still tiny bits of the monoprice stuff at the beginning layers, luckily it disappeared by the time the lettering was printed.
So I printed out most of the major parts. At first I was just going to print out templates to fabricate the roof parts from wood, but I thought, 'why not make as much of this with my 3D printer?' It is a big coach in 7/8ths, and I feared that PLA would not be strong enough for the roof and the roof was too big to print out in one piece so I'd have to glue it. I came up with the idea to buy a 3D pen and join the parts with PLA and it worked. The roof was more than ridgid. I decided that it would be even beefier if I just made the signboard out of one 9 mm thick piece of cedar. I dry fitted all the parts together to make sure my dimensions hadn't drifted. I did have to fabricate a few parts over again, but the siding and everything seems to work out fine, so I can busy myself with redesigning those parts and printing out more of the others before I finish assembly and paint this giant.
I fastened my shapeways scrolled knee braces for the deck. I could never print these on my printer. These were printed in FUD and, like the ornate railing, they are perfect. I'm starting to paint the parts now and apply the decals. I'm etching the plates beneath the side windows (shown in the photo above) and the plate over the front window (just above the lady's hat). One I attach those and paint the inside, I will permanently attach the walls to the deck. Right now they are just held into place by the pressure of the fit.
It took me forever to etch the 3 plates I needed before I coudl assemble. I did two builder plates for Kauila and the number plate for the front of the smoke box. Unfortunately I left the number plate in for too long and I'll have to machine and etch a new one I'll do that later though. I fitted the sides to platform and tested the fit on all the other parts so now, I'm laying out the undercarriage. I'need to fabricate a few more parts like the linkage and air tank and the bolster buffers (which I will print) as well as the mounting plates for the bolsters but I am just laying them out for now.
I've been drying my prints in the sun for almost 7 months now and I've never had them distort or show any sign of getting softer till now. I have 32 pieces of sash to paint and move a little faster I decided to tape one side of the sash to a strip of 3M blue painter's tape; that way I could line them up and paint them without them moving. So I painted the first four pieces very quickly and laid them out in the sun to dry (still on the tape). Thirty minutes later, this is what they looked like!!!! That day was rife with mistakes. The nozzle on my printer was starting to clog so I bought some cleaning filament hoping to resolve the issue only to make it worse. I had to remove the nozzle and scour out the inside of it and change the tube. I got the PLA flowing again, but the bead was erratic and weak. So I had to buy some new nozzles from Amazon. Ten U.S. dollars got me five nozzles and now I'm printing again. I managed to finish painting the sash and test fitting it and painting some parts that I printed up after the new nozzle. I have decided to redo the front threshold plate after receiving some better images. I think I'll have it printed at Shapeways in FXD.
It's been a while since I've done any work on coach 64. Between remodels, repairs and helping my wife take care of my granddaughters I've barely had time. But the real stopper was finding SE 24 inch wheels for my project. The only source I had passed away and they aren't available any more. So, when I did have time I worked on a 3D prototype of the wheels I need and yesterday I printed them out. The lettering is less than fair but I can repair that and carve them by hand. These won't be a permanent solution if I plan on actually pulling the coach behind an engine, but they will be good enough for a stationary model and to test fit everything. Now I need to mill up some axles and paint everything up. If they look good and fit then I'll move ahead on mounting the trucks and detailing the under carriage before I finish up work on the body.
I finally got a chance to turn some axles for this project and prime them. I still need to finish fabricating and assembling a few parts but they are starting to come together really nice. Some day in the future I'd like to have these wheels cast in metal instead of printed in PLA, but who knows how long it will before that technology is cheap enough for me to afford. I have decided to do the leaf springs in SWF if I can figure out what the new name for that material is. It is a lot more durable and flexible than PLA, plus I can have it printed whole instead of parts that require assembly.
I finished all the fussy little parts this week, then assembled them ... Now, I just need to figure out exactly how the brake linkage works so I know which beams to attached the rest of the parts to. It would be nice if the brakes work when I turn brake wheel, but I'll settle for it just looking accurate, working or not.
I've uploaded this kit to Shapeways in WSF, FUD and FXD. I don't think the lettering will come out in WSF, but it will certainly be visible in the FUD materials. https://www.shapeways.com/product/H9FUZBFPU/se-westinghouse-brake-cylinder-kit-sw?optionId=97723464 Meanwhile, I'm just wrapping things up on the undercarriage work. I have to print out the bolster bearing blocks and attach them, then - hopefully - the turnbuckles I ordered will arrive and fit, if they don't I'll have to create the 3D models for them and print them in brass at Shapeways.
I've got quite a bit done. I designed a pair of SE operable couplers and installed them and the linkage. I bought some turnbuckles, but wish I could have printed them, since they aren't really the same as the prototype. As the first image shows, I glassed all the windows except the clerestory windows. And I printed and installed the coupler throw bar on the deck along with a store bought brake wheel. My Duplicator 6 just can't print the wheel for some reason, it won't stick to the platform and even when it does, it looks terrible. Now, I am working on the front buffer. I want it to work the way the original works.
I really wanted to finish the bumpers, but I should have done them before I assembled the whole front end. I also should have printed the brackets out with the beam instead of just a blank beam-- live and learn. I soothed my injured ego by making the sign boards and gluing them to the roof. It is taking shape now.
This is as far as I've gotten to date with this wooden model. Everything on this version is scratch built using combinations of wood, brass, resin and polystyrene. That includes the trucks.
Well, that didn't take long, did it! I finally finished the 3D printed version of coach 64 in 7/8ths scale, last month. I'm just now getting around to updating this site. A lot has happened. I reprinted the roof, making it solid instead of framed. I re-engineered the trucks so that they could be printed with resin and FLA in clearer detail. I completed most of the interior details. At least enough to finish this coach. I still have a long punch list of items I need to do to make it more detailed, and easier to assemble. But I'm ending this thread here, because this coach is done.