[5] The shear-line is the thin line shared by the lock plug and its cylindrical housing.
If a pin sits flush with the circumference of the plug it will allow lock rotation.
Lock cylinders use different length pins in different combinations to create relatively unique key bitting.
Information disclosed in manufacturer manuals is often otherwise difficult to find, as is locksmith material in general.
[6] Lock manufacturers each use specific depth and spacing allowing organized master-key systems to be complex, large, and manageable.
Using manufacturer depths permits easy keying, but often you must deviate slightly for optimum accuracy.
Reinsert the plug taking care not to drop top pins into any unused chamber.