wrote:
I'm using a Hilti drill to drill holes into concrete ceilings.
Drilling overhead with a heavy drill and big bit is making it
difficult to keep the hole straight. The Hilti is more than up to the
job ... the problem is when you're applying upward force, the natural
tendency is to pull the drill toward you or away from you, which makes
for a slanted or "crooked" hole. Any tips on how to keep the drill
straight so as to achieve the straightest possible hole?


Go to a thrift store and find an old three footed walking
cane. The tripod base would make a very light stable platform
on which to mount your drill guide. A piece of 3/16 aluminum
plate with 2 or 3 steel guide rods for a cobbled together drill
holder mounted to the feet should slide straight. If clearance
around conduit and such would make it a problem for the rubber
footed tripod, simple 3" spikes on the flat plate would suffice
for legs. We had a sheet metal shop here in town who's owner
would give me all sorts of scrap pieces of different metals
from the scrap bin, I really mourned the closing of that shop.
I have a portable drill guide like this one that I use:

http://www.garrettwade.com/jump.jsp?...&itemID=105318

I don't think it would fair well with a hammer drill unless
the chuck was changed out to a hammer drill chuck. It could give
you a good idea on how to build your own heavy duty guide.

TDD