|
Don't know about Pretzel, but Troll used to make a self drilling bolt. Do not think for one micro second that this means that it will drill into the rock itself. It fvcking loads of hard work (I got it down to 20 - 45 mins of hammering depending on the rock). Be really careful to inspect the bolt after you've finished drilling, they are prone to cracking. I placed one a Paarl, rapped down the route (which was obviously shite), jugged back up and simply pulled the bolt out (which had broken in half!!!!!!).
|