Subpopulus Hibernia said:
I recently inherited a Rocpec from a fellow caver and am not really sure how much use it is to me. What diameter and depth holes do you normally drill? I use concrete screws requiring 6mm hole c.70mm deep but this looks like it would far too long, and probably bend the narrow drill bit before reaching the bottom...
Normally 6 or 8mm, but I once even drilled some 18mm holes (fucking slow).
With good drills (not some China no-name-brand-garbage) 70mm @ 6mm diameter is absolutly no problem, I did this many times.
It's important you doesn't force the drill holder (here Rocpec) in any direction - keen it loose in your hand while dilling and rotate 90? regulary after each hit. 4-flute-drills are the best.
Don't tap hard, better more often: taptaptaptaptap, not bang..............bang.................bang.
For me such a hole is about 5-10 minutes work, depending on the rock.