Support ring for harpless lampshade

thingiverse

If you've got a lamp that's pretty, and a shade that's also pretty, but the harp-style design of the lamp isn't compatible with your shade, you'll need an adaptor. This might be something like an IKEA lampshade - though your mileage may vary. The internet suggested I'd easily find a huge washer at my local hardware store, one with an inner diameter of 1 3/8 inches and an outer diameter of 3 inches, but that was overly optimistic. Initially, I made this as just a simple washer, but then I got carried away. This support ring fits snugly around a type-A lamp socket, with channels for the wires on my three-wire shade, and towers to hold the shade's ring securely, plus a subtracted-out cone segment to get it better bonded to the socket's flange. I haven't exposed it to the heat of a lamp for hours & hours, so I may need to reprint with more fill if it sags, but Makerbot's draft setting with no raft works great otherwise. (The .3MF file here is from Microsoft's 3D Builder app. If you need to resize the ID or OD, or have different channels, or a different depth cone, you can start with these bits, resize what you need, then subtract the inner cylinder and channels guides from the main disc, then place the cone inside the hole and subtract it as well.)