Why No Part Is Ever Exactly 20 mm: Tolerance Explained | Microns EP 02 #Shorts

Microns · Episode 2: Tolerance

Ø 20.000 mm. No machine on Earth makes this exactly. So engineers decide how wrong it's allowed to be.

• Tolerance is the allowed variation: Ø20 ±0.01 means anything from 19.99 to 20.01 mm is a good part
• Outside the band is scrap, even by 3 µm
• Tolerances decide how parts fit: clearance (spins or slides), transition (locates exactly), interference (pressed in for good)
• A 20 mm H7/g6 fit: hole 20.000 to 20.021, shaft 19.980 to 19.993, gap 7 to 41 µm. One code, read the same worldwide (ISO 286)
• Tighter isn't better, it's costlier. Typical bands for a 20 mm size: turning and milling 52 µm, fine turning and reaming 21 µm, grinding 13 µm, honing and lapping 9 µm
• On the shop floor a GO / NO-GO gauge checks it: GO must enter, NO-GO must not

Limits, fits and gauges are core to ISTC's tool & die courses, after Class 10, AICTE approved:
• Diploma in Mechanical Engineering (Tool & Die), 3 years
• Advanced Diploma in Die & Mould Making, 4 years
https://istckonnect.com/admissions

KNOW YOUR LIMITS.

For ISTCians. By ISTCians. Since 1963.

#ISTCKonnect #Microns #Tolerance #Metrology #Shorts