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?
Kinda depends. On how straight it HAS to be, and how much time you have to
drill X many holes in a day, how many of these holes are you going to drill
and how frequently, and how much equipment you have on hand.
If I (underlined I) had to drill some holes for my own use, I'd get a piece
of 4 x 4 and drill a hole in that. Then I'd drill a starter hole in the
concrete, slide the 4 x 4 on the bit, put the 4 x 4 flat on the ceiling, and
drill a reasonably straight hole.
If it had to be EXACT, I'd put the 4 x 4 on a couple of screw jacks.
If I HAD to drill a bunch of holes every day, I'd make a drill holder (I'm a
welder), and could do that cheaply. One could easily be mounted to the top
of a screw jack and moved in a couple of minutes.
If I were a craftsman and had to do this a lot all the time, I'd have a
welder make me a drill guide, and do consistent accurate work.
It really all depends on how accurate you have to be, and how often you have
to drill the holes.
The 4 x 4 idea would be the hobbyist approach, easy, cheap, and reasonably
accurate for a few holes. Plus, you could keep it on a shelf for future
From there, if it has to be accurate, and it's going to make you money, DO
IT RIGHT THE FIRST TIME.
Good ideas all, and maybe I'm just dense (well, I'm obviously not well
educated about this type of thing at least), but I'm not seeing how a
screw jack would help me hold the drill guide up against the ceiling.
Would there be another way to hold the 4x4 against the ceiling? I'm up
on a six foot scaffolding set with very little room to work ... I love
the 4x4 idea and think it would work for us .... but I'm stumped by
how to hold it in place.
Transmission stand, pipe stand, etc...
Something with a screw adjustment on the top for quick installation/removal.
Any type of stand that would be adjustable for height that would wedge it up
on the ceiling.
Or, have a welder make you a jig that could have a spring action that would
compress as you're drilling.
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:
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.
Stick-on level vials are a good idea and might work well enough.
Depending on the drill and you, it might be possible to hold the
drill on your shoulder, and provide upwards force with your knees.
Should be much easier to keep straight with a little guidance
from a helper. Might need padding on your shoulder or against
your ears ;-)
Given "hilti" and "big bit" suggests that a guide (such as a
chunk of 4x4) might not be accurate enough.
To hold a guide such as this against the ceiling without timewasting
fuss (eg: drilling other holes), what you need is 2 jackposts of some
sort. Not the "real thing", but things more like telescoping cargo
bars. These are essentially just a spring-loaded shower curtain
rod with a locking mechanism.
If you got a long drill bit extension, it'd be a lot easier to keep
Age and Treachery will Triumph over Youth and Skill
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.