Calibration Tip for E3D V6 Hotend
A small, slide on block that attaches directly to the nozzle of the E3D V6 hotend, to which a push button can be attached. This has the advantage of positioning the switch directly under the nozzle during calibration.
I've used a basic 11x11 mm push button, which I glued to the bottom of the block with Araldite epoxy.
The cylindrical hole which holds the nozzle is 8mm in diameter. This gives a very tight fit, so I recommend printing this with a more flexible plastic like nylon (perhaps without any infill), so that it will give and allow the block to slide on.