Review by: sea2peak, 2008-03-29
Though they claim to be 3/8" diameter, I think they may be closer to 10mm (slightly larger than 3/8"). I'm hand-drilling, so I assume if anything, the holes are slightly oversized. I haven't had a problem when using a 2 3/4" length in granite with a 3/8" hole, but I have a difficult time with the 3.5". I would guess the double expansion (3 3/4") bolt would be impossible to hammer into very hard rock. On the other hand, in softer rock where you decide not to use a 1/2" diameter bolt, the 3 3/4" would likely be an excellent choice. Another characteristic that I like is the bolt's relative flexibility, these bolts are not brittle at all; they bend over 90 degrees no problem (yes, I've botched a few placements).