How to drill climbing bolts Etc. Noise Levels. Confirm the hanger will sit flat; otherwise, chisel the rock flat (only) in the area surrounding the hole and beneath the hanger profile. Placing the bolts includes how tight should the bolts fit, how to drill the holes straight. The drill bits were a different type back then and a tad faster than todays common cobalt tipped ones. If you drill in about 3 1/2'' that will leave a 4 1/2'' grip for climbing. Pilot drill your screw holes, and use a countersink bit if you have one. Install t-nuts after the plywood wall panel sections are cut out and before they are installed on the frame. • Drill holes perpendicular to the rock surface. The First Ascent Dec 29, 2017 ยท I would think it all boils down to the quality of limestone you are dealing with and how dimensionally correct of a hole you are able to drill within that rock. twydsgwjgbwhkdeykpmosecflpfljcpeqcxfrbbqnbepeozqhxqrdpckbuskbxxmipxfrnrlnqcrkmnbjb