There are two standard steel hex diameters - 22mm or 25mm. And Our tapered bit and rods come in a variety of taper angles(6 degree, 7 degree, 11 degree, 12 degree)
SUPERDRILL tapered rods are available with high-frequency or fully carburized heat treatments.
Socket Diameter：H19，H22，H25 MM
Shank Dimension：83,108,159 MM
Taper Drill rods
Shank Types + Taper Degree + Rod Length
1，Apply Boring Method processing as same as internationally well-known brand
2，Entire heat-treatment ensuring the excellent quality
3，Accurate dimension of taper degree perfectly matches the bit
Why There are many different Taper?
Different taper angles are used for different rock formations and Rock drills. A wide taper angle is normally used when drilling with high impact hydraulic rock drills in medium hard to hard and abrasive rock formations. Taper angles of 11°and 12° are common on modern rigs.
A narrow taper angle of 7°is used for low impact rock drills and softer rock formations. This angle can also be used if you have spinning problems when using 11° or 12° equipment.
In addition, a 4°46' angle is ideal for soft rock when you’re using pneumatic or hydraulic drill rigs – to prevent bits from spinning or becoming detached.