In reply to barrington1978:
> There is a large climable sea slab near my home town. The slab is slate and devoid of natural protection. Drilling threads mighr seem to be less intrusive to the eye than placing bolts, would this be completely futile from a climbing safety point of view ?
Safety depends on how big you make the thread holes and if you test a few trial ones for ultimate strength.
Bolting acceptance depends on the local climber's ethics and possibly the landowner.
HTH