There are already existing designs for BNC dust caps, but I needed one that could protect my measurement tools without "gap" between the connector and the front plate. This simple design will do just that, it can be parametrized to fit any lenght of connectors and can be easily screwed with at max 1/4 of turn.With the current parameters, the dust cap is a bit loose on the connector, this is the way I like it, but this can be changed by tweaking the parameters in the SCAD file.