When I visited Gary Hinshaw after Christmas, we were commiserating about our 3D printing woes. I’ve been feeling that my printing has gone downhill since I got new resin last year, and hearing that Gary felt the same, I decided to look into it. Well, it turns out that printer calibration is a thing, and so, I downloaded a test model from Ameralabs and printed several copies with slight differences in exposure time, honing in on a slightly shorter exposure than I had been using.
Then some black resin arrived, which I think is going to be better for the trucks, and so I printed an Amerablabs Town with each iteration of the truck thereafter. For this resin, the recommendation from Elegoo underexposed ever so slightly, and I couldn’t get the “antenna” to print at all until I slowed the lift rate. Humidity, warmth and FEP sheet age all probably play a role here too.
Meanwhile, I thickened the bottom chord of the truck so I wouldn’t have to support it over its length, except in the middle where I added a connection to the swing plank. I also softened the bolts on the underside of the truck so I don’t technically have to support them at all, but I will because I think the journals need the support. I’ve also thickened the truss rods on the brake beams because I was losing about one in four.
Finally, I filament-printed a jig to help align the brake hangers. On the prototype, these loops suspend the brake beams from the underframe, but on my models, they will be loose at the top to allow the trucks to swivel and be removed. I included them on my caboose trucks years ago, and I still have a tic from aligning them and cutting them to length. My initial test with the jig shows promise.
Pembroke:87 