∙ Hole in hook
Hole in the hook of the tape measure is where the head of the nail is hooked.
∙ Chip on hook
The chip in the center of the tip of the hook is to prevent the tape measure from coming off the nail even if the tape measure is pulled at an angle.
(There are other theories, such as that the measurement was taken across the threads)
∙ Moving hook
The hook of a tape measure rattles because it is zero-point compensated so that the length is the same whether it is measured by poking or by hooking.
The width of the wobble is the same as the thickness of the hook.
Width of Tape Measure
The width is often indicated on the back of the measure.
The last one, right angle guide, is only an auxiliary function and is not intended to achieve high accuracy.
Here is a summary of some of the lesser-known features of tape measures.
Model Number: HC-115