I don’t know about you but sometimes it feels like I can plan and measure all I want and then I order the parts I think I need and they’re not exactly right. This can be nerve-wracking, annoying, and expensive when you’re spec’ing high-priced parts.

Make: pal Meredith Scheff-King discovered a feature within the indispensable McMaster-Carr catalog that could be a godsend to makers who have access to a 3D printer. Many parts in the online catalog have 3D models attached to them. In this Instructable, Meredith shows you where to get the STEP files so that you can download them, convert to STL, load them into a CAD program, and prepare them for 3D printing.

Now you can print a critical part, test-fit it, and make sure that it’s the part you want before you buy it. Pretty cool, eh?