鋼絲螺套，或可稱為螺套護套，螺紋牙套，一種新型的內螺紋緊固件，用高強度、高精度、表面光潔的冷軋菱形不銹鋼絲**加工而成的螺旋線圈，為高精度內外螺紋同心體，鋼絲螺套裝入工件后形成一個符合國際標準的高精度內螺紋，其各項性能均優于直接在工件上攻絲所形成的內螺紋。
鋼絲螺套安裝后，螺紋孔公差帶取決于鋼絲螺套型面制造公差和鋼絲螺套安裝孔螺紋公差帶；安裝孔的螺紋公差，主要取決于鋼絲螺套安裝孔的攻絲精度，統一螺紋標準為2B、3B。
英制鋼絲螺套在實際應用中使用廣泛。我公司的英制鋼絲螺套型面制作精良。精度等級能達到2B、3B級。所的鋼絲螺套依據的技術標準有BS7751、BS7752，MS33537、MS21209等。
統一螺紋UNC鋼絲螺套型式尺寸規格：
2-56、4-40、5-40、6-32、8-32、10-24、12-24、1/4“-20、5/16"-18、3/8"-16、7/16"-14、1/12"-13、9/16"-12、5/8"-11、3/4"-10、7/8”-9、1"-8、11/8"-7、11/4"-7、13/8"-6、11/2"-6。
粗牙統一螺紋UNC鋼絲螺套型式尺寸及安裝參數（部分）
| 螺紋規格dp | 螺距p | 螺紋公稱長度 | 圈數(W) | 自由狀態下外徑（Dz) | 鉆頭直徑 | 鉆孔深度 | 實際有效長度 | |
| d | L | |||||||
2-56 （0.086) | 0.435 | 1d | 2.2 | 3.0 | 2.7~2.9 | 2.4 | 3.9 | 1.8 |
| 1.5d | 3.3 | 5.25 | 5.0 | 2.9 | ||||
| 2d | 4.4 | 7.4 | 6.1 | 3.9 | ||||
| 2.5d | 5.5 | 9.6 | 7.2 | 5.0 | ||||
4-40 (0.112) | 0.635 | 1d | 2.9 | 2.8 | 3.6~4.0 | 3.1 | 5.4 | 2.5 |
| 1.5d | 4.3 | 4.8 | 6.8 | 3.9 | ||||
| 2d | 5.8 | 6.8 | 8.3 | 5.4 | ||||
| 2.5d | 7.2 | 8.8 | 9.7 | 6.8 | ||||
5-40 (0.125) | 0.635 | 1d | 3.2 | 3.3 | 4.0~4.4 | 3.4 | 5.7 | 2.8 |
| 1.5d | 4.8 | 5.5 | 7.3 | 4.3 | ||||
| 2d | 6.4 | 7.8 | 8.9 | 6.0 | ||||
| 2.5d | 7.9 | 10.0 | 10.4 | 7.5 | ||||
6-32 (0.138) | 0.794 | 1d | 3.5 | 2.8 | 4.5~4.9 | 3.8 | 6.7 | 3.1 |
| 1.5d | 5.3 | 4.8 | 8.5 | 4.9 | ||||
| 2d | 7.0 | 6.7 | 10.2 | 6.6 | ||||
| 2.5d | 8.3 | 8.7 | 11.5 | 8.4 | ||||
8-32 (0.164) | 0.794 | 1d | 4.2 | 3.5 | 5.2~5.6 | 4.4 | 7.4 | 3.8 |
| 1.5d | 6.3 | 5.9 | 9.5 | 5.9 | ||||
| 2d | 8.3 | 8.3 | 11.5 | 8.0 | ||||
| 2.5d | 10.5 | 10.7 | 13.7 | 10.1 | ||||
10-24 (0.190) | 1.058 | 1d | 4.8 | 2.9 | 6.2~6.6 | 5.2 | 9.0 | 4.3 |
| 1.5d | 7.2 | 5.0 | 11.4 | 6.7 | ||||
| 2d | 9.6 | 7.1 | 13.8 | 9.1 | ||||
| 2.5d | 12.1 | 9.2 | 16.3 | 11.6 | ||||
12-24 (0.216) | 1.058 | 1d | 5.5 | 3.5 | 6.8~7.2 | 5.8 | 9.7 | 5.0 |
| 1.5d | 8.2 | 5.9 | 12.4 | 7.7 | ||||
| 2d | 11 | 8.3 | 15.2 | 10.5 | ||||
| 2.5d | 13.7 | 10.7 | 17.9 | 13.2 | ||||
| 1/4"-20 | 1.27 | 1d | 6.4 | 3.4 | 8.0~8.4 | 6.7 | 11.5 | 5.8 |
| 1.5d | 9.5 | 5.7 | 14.6 | 8.9 | ||||
| 2d | 12.7 | 8.0 | 17.8 | 12.1 | ||||
| 2.5d | 15.9 | 10.3 | 21.0 | 15.3 | ||||
| 5/16"-18 | 1.411 | 1d | 7.9 | 4.0 | 9.7~10.2 | 8.4 | 13.5 | 7.2 |
| 1.5d | 11.9 | 6.6 | 17.5 | 11.2 | ||||
| 2d | 15.9 | 9.3 | 21.5 | 15.2 | ||||
| 2.5d | 19.8 | 11.9 | 25.4 | 19.1 | ||||
| 3/8"-16 | 1.588 | 1d | 9.5 | 4.4 | 11.5~12.0 | 10 | 15.9 | 8.7 |
| 1.5d | 14.3 | 7.2 | 20.7 | 13.5 | ||||
| 2d | 19.1 | 10.1 | 25.5 | 18.3 | ||||
| 2.5d | 23.8 | 12.9 | 30.2 | 23.0 | ||||
| 7/16"-14 | 1.814 | 1d | 11.1 | 4.5 | 13.4~14.0 | 11.6 | 18.4 | 10.2 |
| 1.5d | 16.7 | 7.9 | 24.0 | 15.8 | ||||
| 2d | 22.2 | 10.3 | 29.5 | 21.3 | ||||
| 2.5d | 27.8 | 13.1 | 35.1 | 26.9 | ||||
| 1/12"-13 | 1.954 | 1d | 12.7 | 4.8 | 15.2~15.8 | 13.2 | 20.5 | 11.7 |
| 1.5d | 19.1 | 7.9 | 26.9 | 18.1 | ||||
| 2d | 25.4 | 10.9 | 33.2 | 24.4 | ||||
| 2.5d | 31.8 | 13.9 | 39.6 | 30.8 | ||||
