Fitting and sizes?
Fittings in and around the coffee machine are measured in BSP thread sizes and more specifically BSPP thread, which is the parallel type of the BSP thread. In this version, neither the male or the female thread has a taper, meaning that the connection requires a seal or washer (usually teflon or soft metals such as copper) in order to completely seal. Another common way to seal fittings is by using liquid thread sealants which are becoming increasingly common and it makes the fitting connection neater and is a quicker way of sealing fittings.