Tolerance Lens

Shows the tolerances McMaster-Carr product pages leave out, computed from the standard the part cites (ISO, ASME, DIN).

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, hex socket and length • Button, flat and pan head screws: head diameter and height, countersink angle, hex socket and length • Shoulder screws: head, thread length and shoulder length • Hex bolts and screws: head, shank and length • Hex nuts: width across flats and height for standard metric and inch hex nuts • Retaining rings: ring thickness, free diameter, and groove diameter and width for standard metric rings • Wrapped bushes: outside diameter, wall, and the housing and shaft fit for metric PTFE-lined bushes • 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 Most parts come with a dimensioned sketch whose letters match the table. 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. • If McMaster prints a different tolerance from the standard's, the panel withholds its own number rather than contradict the page. • Every number shows its source standard. Privacy: runs only on mcmaster.com and works in your browser. It sends nothing unless you send a problem report with "Report this page". BETA: always verify critical tolerances against the standard itself before use. Not affiliated with, authorised or endorsed by McMaster-Carr Supply Company.