1. Thread pitch:2.5mm-3.0mm
2. Thread angle:60 / 75
3. Specifications: D12mm-50mm. 4. Model: ordinary-type, forward-and-back forward-thread type and caliber-changed type 5. Screw thread parameter| Diameter (MM) | Thread Pitch (MM) | 
| 12 | 1.75 | 
| 14-22 | 2.5 | 
| 15-40 | 3.0 | 
| 50 | 40 | 
| Bar Diameter(mm) | CouplerOuter Diameter(mm) | CouplerLength(mm) | Thread Size (mm) | Weight(kg) | 
| 12 | 18 | 32 | Directly Rolling Rolling after StripperM13*2.0 M12.0X2.0 | 0.03 | 
| 14 | 21 | 36 | M15*2.0 M14.5X2.0 | 0.05 | 
| 16 | 23 | 42 | M17*2.5 M16.5X2.0 | 0.07 | 
| 18 | 28 | 46 | M19*2.5 M18.5X2.0 | 0.13 | 
| 20 | 30 | 50 | M21*2.5 M20.5X2.0 | 0.15 | 
| 22 | 33 | 51 | M23*2.5 M22.5X2.0 | 0.19 | 
| 25 | 38 | 62 | M26*2.5 M25.5X2.5 | 0.30 | 
| 28 | 43 | 68 | M29*3.0 M28.5X3.0 | 0.43 | 
| 32 | 48 | 76 | M33*3.0 M32.5X3.0 | 0.58 | 
| 36 | 53 | 84 | M34*3.0 M36.5X3.0 | 0.95 | 
| 40 | 60 | 92 | M41*3.0 M40.5X3.0 | 1.25 | 
| 50 | 70 | 114 | M45*3.5 M50.5X3.0 | 2.37 | 


2. The straight thread connection of positive and negative threaded reinforcement is used for reinforcement connection, in which the reinforcement cannot rotate, but one end of the reinforcement can move axially. For example, beam ends and capped reinforcement connections. The steel bar connecting sleeve has positive and negative threads, which can loosen or tighten two steel bars in one tightening direction. The classification and application knowledge of steel sleeves shall be steel connecting sleeves with positive and negative threads.
Because the material of the reinforcement connecting sleeve does not meet the requirements and cracks appear after processing, it is absolutely necessary to ensure the material quality. When entering the site, the casing must have a certificate of conformity. During transportation and storage, the casing shall be properly protected from rain, pollution and mechanical damage. The operation of the machine tool shall be carried out in strict accordance with the operating procedures of the machine tool.