I'd like to ask basic questions about drilling these holes in concrete:
http://i.cubeupload.com/ILcx5v.jpg
I try to research new tasks before I do them but unexpected questions
always seem to arise when I actually do stuff such as when I drilled
concrete for the first time in order to mount a harbor freight
tire-changing machine onto my backyard sidewalk.
http://i.cubeupload.com/YfywQp.jpg
The 1/2-inch wide bit I bought was in a 6-pack at Harbor Freight item
#62791 "Warrior 8-inch SDS Masonry Bit Set" with "shank style SDS" and the
drill I bought is the Harbor Freight item #62383 "Chicago 1/2-inch Variable
Speed Reversible Hammer Drill", but it says nothing of the "shank style".
http://i.cubeupload.com/usQnEW.jpg
But no matter how many times I cinched down the chuck evenly along the
three keys, the bit was wobbly in the chuck hole.
http://i.cubeupload.com/5bOwO9.jpg
So my first question is whether I bought the right kind of bits because the
bits have 2 grooves in them while the chucks have 3 keys:
http://i.cubeupload.com/UtC6fv.jpg
The second question is whether we're supposed to use water when drilling
through concrete. It didn't seem to matter to the drilling, which was like
drilling into butter anyway (so maybe my concrete sucks)?
http://i.cubeupload.com/f1VI2I.jpg
The third question is how deep is most backyard sidewalk concrete? I had to
drill a 1/2-inch wide 1-5/8ths-inch deep hole for the 3/8" drop-in anchors:
http://i.cubeupload.com/UEoGP8.jpg
But when I drilled the holes, I realized the soft concrete was only about
that thick (so the bottom of the 1-5/8ths-inch hole was in soft small
pebbly gravel!
http://i.cubeupload.com/KkzB6e.jpg
Is it normal for concrete to be poured so thinly?
http://i.cubeupload.com/7umFkQ.jpg
One mistake I made was to buy 3-inch long 3/8ths-inch hardware store (Home
Depot) bolts (which are about 1/4 inch too long) but Home Depot doesn't
sell quarter-inch increments), one of which snapped off below ground as I
was screwing it in to the anchor bolt (which was set with the proper set
tool).
http://i.cubeupload.com/gplfkB.jpg
I suspect I should have gotten stainless steel bolts but Home Depot doesn't
sell them. Where would you get four 2/3/4-inch 3/8-inch stainless steel
bolts?