I'd like to ask basic questions about drilling these holes in concrete:
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.
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".
But no matter how many times I cinched down the chuck evenly along the three keys, the bit was wobbly in the chuck hole.
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:
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)?
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:
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!
Is it normal for concrete to be poured so thinly?
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).
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?