Metric ISO-thread ISO 965    Gauge dimensions ISO1502

Tolerance zone Tolerance zone external thread Tolerance zone internal thread
fine 4h 5H
medium for threads 1-1.4mm
6h
for threads > 1.4mm
6g
for threads 1-1.4mm
5H
for threads > 1.4mm
6H
coarse 8g 7H


BSW & BSF threads BS 84    Gauge dimensions BS919

External thread close class medium class free class
Internal thread medium class normal class normal class
 


Cylindrical pipe threads DIN ISO228 Part1    Gauge dimensions DIN ISO 228 Part 2

Tolerance Class external thread / bolt medium A coarse B
Tolerance Class internal thread / nut medium
 


ISO metric trapezoidal threads DIN 103    Gauge dimensions DIN 103 Part 9
Tolerance zones group N (normal)

Tolerance Classes Tolerance Zone
external thread
Tolerance Zone
internal thread
medium (m) 7e 7H
coarse (g) 8c 9H
 


Round thread DIN 405-1, 405-2    Gauge dimensions DIN 405-3
Tolerance zones group N (normal)

Tolerance zone external thread Tolerance zone internal thread
7h and 7e 7H
 


Unified inch screw threads BS1580    Gauge dimensions BS 919
Tolerance zones group N (normal)

Tolerance zone external thread
External Thread 1A 2A 3A
Internal Thread 1B 2B 3B
 

Threaded Components


ISO metric threads to BS3643:1981 & BS919 Pt3:1968.


Unified threads to BS1580:1965 & BS919 Pt1:1960



 


Some Basic Profiles

ISO, UN Threads - BS3643, BS1580



Withworth Threads & G- Series BS84, BS2779



Trapezoidal - BS5436



Round Thread - DIN405



Metric Butress



Butress - BS165X



MJ & UNJ Threads BS6293, BS4084



PLAIN DIAMETERS

Gauge Tolerance disposition
- Plug Gauges

Gauge Tolerance disposition
- Ring Gauges


This diagram shows the relationship between product tolerancing and gauge tolerancing. The practice in the UK is to apply tolerances in accordance with BS969:1982 but we can of course supply to other national and international standards.