Bordo SWIVEL PEN DEBURRING TOOL With SE10 Blade
 
Chamfering is the process of reducing the 90° angle of the end of a piece of plastic pipe, to something around 45°.
 
This serves two vital purposes:-
 
It allows the pipe to pass easier through mechanical fittings i.e. not get caught on the O-ring. However, where pipe liners have been used, chamfering is not required as the liner itself has a chamfered end.
For pipe and fittings that are joined with solvent cement, it allows the cement to form a ring around the end of the pipe, creating a stronger connection and massively decreasing the chance of a leak.