Similar blanks and different locating references

An authorized locksmith training exercise presents two visually similar key blanks and an instructor-owned demonstration cylinder. One blank uses a shoulder reference, while the other uses a tip reference under its equipment data. A trainee proposes using the same machine position simply because both blades fit partway into the keyway. The available drawings show the intended profile and locating dimensions, but the exercise supplies no permission to modify a customer lock or override a restricted-key arrangement. Students must identify which information establishes compatibility and how the locating reference affects interpretation of the drawing. The task is about measurement and component identification on training equipment, not a procedure for gaining access to someone else property or a guarantee that partial insertion proves correct operation.