On 16/02/2009 nmonteith wrote:
>In softer rock they will need periodic tightening as the rock is slightly
>crushed in the hole over time.
Even if the nut needs tightening to prevent the hanger falling off, the great benefit is that loads on the bolt actually tighten the bolt's grip on the rock (not so with trubolts, of course). It is also much easier to check that a nut is loose, than to check that glue has been mixed and applied correctly on a glue-in. |