Two rods can be connected seamlessly by the coupler, and there will be no grout leakage when grouting.

For SDA bolts, the coupler and the hollow bar must meet equal strength requirements. The coupler, essentially a threaded sleeve, connects to the hollow bar through threads and is used to extend it. The strength of the threaded connection between the coupler and the hollow bar directly affects the overall strength of the self-drilling anchor bolt and is crucial for ensuring that the coupler and the hollow bar are of equal strength.