Everything we have written
Measurement, materials, decisions and object studies. Each page answers one question about printing a replacement part, in the order you would actually need it.
Print it, or buy the spare?
3D printing is very good at a narrow band of replacement parts, and quietly dangerous outside it. Here is where we draw the line.
Discontinued parts: print the spare, or hunt one down?
Half the small parts people need are not sold any more. There are three sources left, and printing is only one of them.
3D printed brackets
A bracket is a shape that carries a force from one screw hole to another. Print it without deciding which way that force runs and it will do the job once.
3D printed caps and plugs
A cap closes something. What it closes decides everything about it: a dust plug, a threaded cap and a sealed cap are three different parts that happen to look alike.
3D printed clips and retainers
A clip is a beam that bends once and has to come back. Everything that decides whether it survives the second click happens before the first layer: the undercut, the arm length, the layer direction at the root.
3D printed covers and lids
A cover is mostly a flat panel with one job: close an opening and stay closed. The numbers that decide it come from the housing, not from the lid that went missing.
3D printed knobs and dials
A knob is a grip wrapped around a joint. The grip is easy. The joint is the part that decides whether the knob turns the shaft or slips on it.
3D printed spacers and feet
A spacer is a block with a hole. A foot is the same block with a softer bottom. Both are easy, and both still fail when the thickness is guessed or the bore is drilled to the wrong number.