There are a variety of mortar rakes available with slight variations in their designs.
Mortar rake shank
The green circles highlight the shank, which is the part of the mortar rake that connects to the power tool.
The shank is either gripped by a drill chuck…
…Or screws onto the spindle of an angle grinder…
…Or, the shank screws onto an adaptor which in turn screws onto an SDS plus drill.
Shank size
The small arrows to the left highlight the width of the shank. This width is usually measured in millimetres, abbreviated to an ‘M’, and referred to as the ‘thread’ size. Most mortar rakes are designed to fit on small angle grinders which take a 14mm mortar rake, written as ‘M14’.
The width corresponds to the pattern of the threads either inside the shank (the ‘female’ thread)….
…or on the exterior of the shank (the ‘male’ thread), of the mortar rake.
Mortar rake cutting / grinding section
The cutting or grinding section of the tool is highlighted in yellow. There are lots of variations in the design of cutting or grinding sections of mortar rakes, but all of them are designed to fit in the channels of mortar between brick and stonework. Their cutting / grinding sections have small diameters which enables them to move up and down as well as along the mortar channels.
The cutting/grinding section of mortar rakes consists of either flutes (right) or a gritted surface (left).