On Jan 15, 9:31*pm, "The Medway Handyman"
wrote:

The 8mm taper drill guide looks pretty much like an 8mm masonry drill and
appears to be a taper fit. *I assume the drift keys are to remove it, but
why 2?

Someone somewhere is asking where his drift key is.

The pilot drill is a masonary drill. You can leave it in place when
drilling a solid wall but it's not needed once the core drill is far
enough in to guide itself.
If you go though a cavity wall, either go through from one side
(without hammer), or drill a pilot hole smaller than 8mm and core
drill from both sides. This leaves a neater hole as you break out into
the cavity. Remove the pilot drill as soon as the core is self guiding
or the pilot bit will fall out and disappear into the cavity.

Use a drill with a clutch or make sure the kick when the drill snags
is restrained. A pipe on the side handle and against the floor will do
this. A clutch is better though.

John