You press the holding ring toward the body of the drill and slightly twist and pull the bit away from the chuck.
Some Hilti bits come 24 " long.
That is a drill bit designed to remove partial drill bits that have broken in a hole
That's hard stone, don't even bother with a regular drill ! -You need a Hilti or a large Bosch rotary hammer drill with masonry bit that fits it. You can rent these at many stores if you don't think it's worth buying.
Normally with a chuck key.
The best drill for hard concrete is one with a rotary hammer action such as a Hilti or Bosch.
A Hilti branded hammer drill can be purchased from any major home improvement or tool supply outlet. Outlets such as Home Depot and Lowe's carry these items, as well as online retailers such as eBay and Amazon.
I believe that's SDS.
It has hammer action, which I assume is what you mean.
Hilti brand drills can be purchased at Home Depot and other home improvement centers that are certified retailers. The Hilti website features a locator tool to assist in finding a retailer in your area. They are also listed for sale on eBay and Amazon.
If you have the drill in your hand with the chuck away from you, if the rotation goes clockwise it is going forward and if it is counterclockwise it is going in reverse. When you use the drill you usually go forward. To remove the drill bit look for the reverse lever and once it is going counterclockwise place your hand on the front part of the chuck and the drill bit should be released.
To remove a nail after the head breaks off simply drill through the nail with an equal sized drill bit.
The wedge on a drill is the cutting edges on the end of the drill bit. The sharp edges grab and "wedge into" material to remove it.