Cylindrical head machine screws
GB2671.2
Diameter range: M2-M12 Length range: 4mm-100mm
| standard | GB national standard |
|---|---|
| head shape | cylinder |
| Groove | plum blossom trough |
| Thread | Fully threaded |
| (mm) | M2 | M2.5 | M3 | M4 | M5 | M6 | M8 | M10 | M12 | M14 | M16 | M18 | M20 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P | 0.4 | 0.45 | 0.5 | 0.7 | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 |
| dk(max) | 3.8 | 4.5 | 5.5 | 7 | 8.5 | 10 | 13 | 16 | 18 | 21 | 24 | 27 | 30 |
| dk(min) | 3.62 | 4.32 | 5.32 | 6.78 | 8.28 | 9.78 | 12.73 | 15.73 | 17.73 | 20.67 | 23.67 | 26.67 | 29.67 |
| da(max) | 2.6 | 3.1 | 3.6 | 4.7 | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | 20.2 | 22.4 |
| ds(max) | 2 | 2.5 | 3 | 4 | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 |
| ds(min) | 1.86 | 2.36 | 2.86 | 3.82 | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | 17.73 | 19.67 |
| k(max) | 2 | 2.5 | 3 | 4 | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 |
| k(min) | 1.86 | 2.36 | 2.86 | 3.82 | 4.82 | 5.7 | 7.64 | 9.64 | 11.57 | 13.57 | 15.57 | 17.57 | 19.48 |
| r(min) | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | 0.25 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.6 | 0.8 |
| No. | T6 | T8 | T10 | T20 | T25 | T30 | T45 | T50 | T55 | T60 | T70 | T80 | T90 |
| e | 1.75 | 2.4 | 2.8 | 3.95 | 4.5 | 5.6 | 7.95 | 8.95 | 11.35 | 13.45 | 15.7 | 17.75 | 20.2 |
| t(max) | 0.84 | 1.04 | 1.27 | 1.8 | 2.03 | 2.42 | 3.31 | 4.02 | 5.21 | 5.99 | 7.01 | 8 | 9.2 |
| t(min) | 0.71 | 0.91 | 1.01 | 1.42 | 1.65 | 2.02 | 2.92 | 3.62 | 4.82 | 5.62 | 6.62 | 7.5 | 8.69 |
| steel | Stainless steel | nonferrous metals | ||
| General technical conditions | GB/T 16938 | |||
| Thread | tolerance | 12.9/12.9: 5g6g; | ||
| Other performance levels: 6g | ||||
| standard | GB/T 193、GB/T 9145 | |||
| Mechanical properties | Grade | d＜3mm: according to the agreement; | 、A2-70b | d＜3mm: according to the agreement; |
| /12.9 | d≥3mm：CU2、CU3 | |||
| standard | d＜3mm: according to the agreement; | GB/T 3098.6 | d＜3mm: according to the agreement; | |
| GB/T 3098.1a | d≥3mm：GB/T 3098.10 | |||
| tolerance | Product grade | A | ||
| standard | GB/T 3103.1 | |||
| Hexagonal flower shape | GB/T 6188 | |||
| surface treatment | Without treatment; | Simple handling; | Simple handling; | |
| Electroplating technical requirements shall comply with GB/T 5267.1; | Passivation treatment technical requirements according to GB/T 5267.4 | Electroplating technical requirements according to GB/T 5267.1 | ||
| Technical requirements for non-electrolytic zinc flake coating according to GB/T 5267.2 | ||||
| If other technical requirements or surface treatment are required, it should be agreed upon by the supplier and the buyer. | ||||
| surface defects | GB/T 5779.1； | - | ||
| Performance level 12.9/12.9 according to GB/T 5779.3 | ||||
| Acceptance and packaging | GB/T 90.1、GB/T 90.2 | |||
| a For screws that are not suitable for tensile testing, a hardness test should be carried out on the screw cross section. | ||||
| b For stainless steel screws cut from bars, A1-70 (for specifications ≤M12) and A1-50 (for specifications >M12) are allowed, but the performance grade should be marked on the screws. | ||||
