The Dummies’ Guide to Shank Adapter Failures

Table of Contents

With the rapid development of high-frequency, high-power full-hydraulic rock drilling equipment, the market’s requirements for the matching and manufacturing technology of supporting rock drilling tools have increased. Under such a background, shank adapters with various structures that are fully machined and formed with high precision are produced.

The shank adapter is the transmission connection part between the rock drill and the drill rod, and its main function is to directly bear the impact and the torque of the rock drill. During the drilling process, the shank adapter end is subjected to high frequency and high energy axial and torsional high amplitude stress cyclic impact of the rock drill piston. Among them, 75%-87% of the energy transfer must be transferred for drilling, and 13%-25% of the remaining energy is in its internal consumption such as contact, wear, and heat generation. Therefore, the work of the shank adapter is in a stress state where high-amplitude stress cycles, severe external friction, and internal friction exist simultaneously, and its service life will be severely tested.

Nowadays, as one of the supporting drilling tools for rock drilling, the shank adapter has developed into an indispensable and important accessory in modern rock drilling tools. Because of the particularity of the working environment, it is also one of the large quantities of scrapped consumables in the rock drilling site. Although the failure of the shank adapter is inevitable, we can adjust to prevent the failure of the shank adapter, to improve the service life of the shank adapter.

shank adapter

13 Ways to Solve Shank Adapter Failures

1. The solution to the impact marks, chipped corners, and mushroomed end caused by misalignment due to worn bushings: Replace worn components.

2. The solution to the failure of approx. 25mm from strike face caused by worn chuck driver: Replace worn components.

3. The solution to the failure at the top of the spline due to lack of lubrication: Grease rock drill regularly.

4. The solution to the failure at the top of the spline due to excessive feed force: Monitor coupling temperatures and adjust feed pressure according to recommendations.

5. The solution to the failure at the top of the spline due to worn chuck driver or front bushing: Replace worn components.

6. The solution to the failure across splines due to heavy rotational torque: Adjust drilling pressures.

7. The solution to the wear on the bottom of the spline’s shoulder caused by excessive rotation when the drilling tool is retracting string: Adjust drilling pressures.

8. The solution to the failure at the front head caused by misalignment from worn front bushing: Replace worn components.

9. The solution to the failure of above threads caused by hole deviation: Employ straight hold drilling devices or systems.

10. The solution to the failure in the main body of threads caused by improperly joined in coupling sleeves too much times: Replace worn components. Do not put a worn coupling sleeve on a new drill rod. Change out-coupling sleeves with a new shank adapter.

11. The solution to the chipped thread end due to the shank adapter not being properly coupled to the drill rod: Replace the damaged or worn coupling sleeves.

12. The solution to the chipped thread end due to the drill rod end not being square: Forward for analysis.

13. The solution to pitting and galling on splines caused by excessive rotation in the soft or broken ground: Adjust the drilling pressure.

To sum up, the failure of the shank adapter is the same as the failure of other rock drilling tools, and there are many forms. However, a large part of the failure of the shank adapter comes from the wear or damage of other components, so in order to improve the efficiency of the shank adapter, regular inspection and lubrication of other rock drilling tools are also very important. At the same time, whether the geometry design of the shank adapter shape and the selection of parameters is reasonable or not, directly affects the performance of the rock drill and supporting rock drilling tools, and affects the rock drilling efficiency of the entire drilling process. Therefore, the design principle of the shank adapter, on the one hand, to meet the high frequency, high power impact, and rotational stress requirements of the rock drill, on the other hand, must also consider the geometric shape and size of the geometrical dimensions of the cylinder liner of the rock drill, which requires the shank adapter supplier need to be professional enough, so we must choose a reliable supplier when buying the shank adapter, which is also a way to improve the efficiency of the use of rock drilling tools.

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