so that is fits into the screw nicely and for health and safety reasons i don't know about because i have bad health and safety.
with a flat tip
The tip of the screwdriver
you can use a flat tip screwdriver or a nut driver Turn counter clockwise to loosen
a flat head screwdriver is used to drive or to screw screws.
Phillips, or Phillips head, refers to the shape of the screwdriver's tip. It forms an X or a cross at the tip, instead of being straight as in a flat head. Phillips head screws and screwdrivers are less likely to slip while being turned, but it's more important to use the right size to avoid damaging the screw head.
There is the tip and the handle, I don't understand 'bottom' in a screwdriver.
Is there a standard ? - I have screwdrivers in 5 flat sizes ranging from 0.75 mm x 2mm wide, up to 2.5 x 18mm.
Very close to the tip of the screwdriver. The lip of the tin that the screwdriver presses down against is the fulcrum. The load is the tin lid, under the lip of which the tip of the screwdriver sits.
Inclined plane
an awl
The post between the handle and the tip that turns the screw.
The post between the handle and the tip that turns the screw.
On a center fire gun, rounded tip. On a rimfire gun, the tip is shaped a bit like the tip of a screwdriver blade.