Basics of Solidworks

A: The trap is the silent 25.4 factor. SolidWorks allows model units and drawing units to diverge, and the sheet scale is a third multiplier. You kill the risk by locking model units first, then verifying the drawing consumes them correctly, and only then trusting the title block note. Reversing that order lets an inch-based model masquerade as metric all the way to the CNC.

A: The boundary is the tolerance class. With ISO 2768-m, every untoleranced linear dimension quietly carries a limit. Miss that, and you either over-tolerance the drawing or under-control a fit. SolidWorks won’t warn you; the title block note is the contract.

A: The number that bites is the clearance delta. ISO Normal gives you predictable bolt slip without chasing GD&T later. Mixing ANSI tables or hard-coding diameters forces you to own every tolerance interaction across supplier drawings.

A: The trigger is the rebuild. SolidWorks is parametric; kill a parent and children complain immediately. Assuming it’ll self-heal is how you end up with a 3% geometry drift no one notices until mass properties change.