PVC pipe adapter, 40 mm to 50 mm
A reducing coupler that connects a 40 mm PVC pipe to a 50 mm pipe for low-pressure drains, dust collection or a garden gravity feed. One side is a socket with a 40.4 mm bore and 30 mm depth, the other a 50.4 mm bore 35 mm deep, joined by a conical section with a 3 mm wall and an internal flow path that steps as little as possible. A 0.5 mm chamfer at each mouth eases the pipe in, and printing upright with three or more walls keeps it round and stiff.
PVC sizes differ between metric and imperial systems and between manufacturers, so typing the measured outer diameters into SpeakCAD beats guessing at a downloaded coupler. Preview free in the browser and ask for a longer socket, a male-to-female version or a 45-degree bend.
Design a PVC reducing coupler. Socket A bore 40.4 mm, 30 mm deep. Socket B bore 50.4 mm, 35 mm deep. Conical transition 15 mm long between them, wall 3 mm throughout, 0.5 mm internal chamfer at each mouth. Overall length 80 mm, smooth internal flow path.