Tolerance Lens

McMaster-Carr product pages tell you which standard a part meets, but often not the tolerance that standard gives. Finding it means pulling up the standard and looking up the right size. Tolerance Lens does that lookup for you. Open a product page, click the panel, and see the tolerance limits for that exact part, with the standard each number comes from. What it covers (beta): • Dowel pins: diameter and length • Socket head cap screws: head and length • Hex bolts and screws: head, shank and length • Spring pins: free diameter, and length for coiled pins and inch slotted pins • Threads: pitch diameter limits by class, inch and metric; major and minor diameter on metric threads • Hex nuts: width across flats and height for standard metric and inch hex nuts, with a dimensioned sketch Tolerances come from the published ISO, ASME and DIN standards that McMaster-Carr cites for each part. How it behaves: • If McMaster already prints the tolerance, the panel defers to McMaster's number. • If the page cites no standard, or a value isn't available yet, the panel says so and why. It never guesses. • Every number shows its source standard. Privacy: runs only on mcmaster.com, works entirely in your browser, collects and sends nothing. BETA: always verify critical tolerances against the standard itself before use. Not affiliated with, authorised or endorsed by McMaster-Carr Supply Company.