The screw threads being locked by polygonal deformation of one or more turns of the thread
This deformation results in a powerful locking on the sides of the screw thread and counteracts the unscrewing effects of dynamic stresses, vibrations and thermal loads
| Metric | UNC | UNF | L |
| M2*0.4 | 1/4"-20 | 1/4"-28 | 1d 1.5d 2d |
| M2.5*0.45 | 3/8"-16 | 5/16"-24 | 1d 1.5d 2d |
| M3*0.5 | 7/16"-14 | 3/8"-24 | 1d 1.5d 2d |
| M4*0.7 | 1/2"-13 | 7/16"-20 | 1d 1.5d 2d |
| M5*0.8 | 5/8"-11 | 1/2"-20 | 1d 1.5d 2d |
| M6*1 | 3/4"-10 | 9/16"-18 | 1d 1.5d 2d |
| M8*1.25 | 1"-8 | 5/8"-18 | 1d 1.5d 2d |
