For thread size M8 this annex gives information on screw thread limits for.
a) internal screw threads tapped oversize to tolerance class 6AZ and 6AX;
b) external screw threads undersize threaded to tolerance class 6az.
The internal screw thread limits for M8 for tolerance class 6AZ and 6AX are specified in
Table .
Tolerance quality: medium
Thread engagement group: normal
Tolerance classes: 6AZ and 6AX
| Thread | Length of thread engagement | Tolerance class | Major diameter a | Pitch diameter a | Minor diameter a | |||
|---|---|---|---|---|---|---|---|---|
| D | D 2 | D 1 | ||||||
| over | up to and including | min. c | max. | min. | max. | min. | ||
| M8 | 4 | 12 | 6AZ | 8.325 | 7.673 | 7.513 | 7.237 | 6.972 |
| 6AX | 8.255 | 7.603 | 7.443 | 7.167 | 6.902 | |||
|
a) Dimensions apply to internal screw threads after galvanizing and
tapping oversize. |
||||||||
The external screw thread limits for MB for tolerance class 6az are specified in Table
B.2.
Tolerance quality: medium
Thread engagement group: normal
Tolerance class: 6az
The actual root contour shall not at any point transgress the basic profile.
For hot-dip galvanized screw threads, the tolerances apply to the parts before galvanizing.
After galvanizing, the actual thread profile shall not in any point transgress the maximum
material limits for tolerance position h and is intended to mate with internal screw threads
of tolerance position H or G only.
| Thread | Length of thread engagement | Major diameter | pitch diameter | Minor diameter(for stress calculation) | Root radius | |||
|---|---|---|---|---|---|---|---|---|
| d | d2 | d3 | ||||||
| over | up to and including | max. | min. | max. | min. | max. | min. | |
| M8 | 4 | 12 | 7.675 | 7.463 | 6.863 | 6.745 | 6.142 | 0.156 |