Transcription of Flank angle tolerances for metric threads - FMS
1 Flankangle Flank angle tolerances for metric threads The following tolerances are the allowable variations in 30O basic half- angle of screw threads and apply both to external and internal threads Pitch diameter tolerance Pitch diameter tolerance Grade 6 Grade 4. Pitch deg. Min. deg. Min. 3 30 2 15. 3 20 2 05. 3 05 2 00. 2 55 1 55. 2 40 1 45. 2 30 1 35. 2 25 1 30. 2 20 1 30. 1 2 05 1 20. 1 50 1 10. 1 40 1 05. 1 35 1 00. 2 1 30 0 55. 1 20 0 50. 3 1 10 0 45. 1 05 0 45. 4 1 05 0 40. 1 00 0 40. 5 0 55 0 35. 0 55 0 35. 6 0 50 0 35. 8 0 45 0 30. The Flank angle on a thread with for example, a 2 mm Grade 6 pitch can vary between 60O 3O. Anyone using thread measuring wires or micrometer thread inserts to measure thread pitch diameter should be aware of these tolerances . Especially when measuring pitch diameter with measuring wires, a false sense of accuracy can be made when subtracting the constant from the measured value, especially when using a micrometer.
2 Further information on this can be seen in under General Information Measurement related.
