Because…..you make stupid sh!t that nobody else on earth would consider. After an unproductive search for a temperature sensor to work with my stock 50 Pontiac gauge and the small block heads…well, the lathe. So I turned down the stock sending unit and removed all threads to 16mm. The bored a 3/8 fnpt to 1/4 mnpt to 16.2mm. Faced it down to have 8mm of engagement to maximize the sensor protrustion. Turned the hex off the sensor and soldered it together. Pressure tested under water at 60 psi. Finally I have a gauge that works.