I want to build stairs on our land, but need to drill into rock
(granite i think) in order to make posts to connect the stairs to. My
question is... is there a drilling tool (preferably as powered and
portable) that will drill through rock and make a nice big hole?
Call your rental yards. Ask for Cobra, Berema or Pionjar
Tell them what hole size you need to see if they stock the bit. If
you have granite, it should
be no problem. Plain quartz is an entirely different story. Make
sure the unit starts
and runs nicely in the yard and take notes on any control
If you get a combination breaker/drill unit, be clear on the
and be positive it is FULLY seated in the selected position.
Unless you want to bell mouth your holes, you will need to have a
flattened surface to start
your drilling. If that means chisel and grind or just plain
grinding for accuracy, that isn't a problem.
Begin your hole as perpendicular as possible, slowing down the rpm
on the drill and use an
assistant or your foot on the bit to help with accurate placement.
If you want a really clean
job, start with a drill and a sledge to make a smaller, shallow
pilot hole the bit will seat in.
Once you are accurately seated, let out the rpm to a manageable
range. Carefully pulling the
unit up and down every so often will help clear the drilled spall
from the hole, making
for easier operation. Whatever you do, don't drill all the way
through the rock. That would
not lead to a joyous result.
Also, the usual caveats about a cartridge mask, eye protection and
ear muffs apply.
Ed! You are a gentleman and a scholar!
Your response really led me in the right direction. I have a few more
Is this a job for someone unexperienced like me? That is, should only
people who really know what they are doing try this? Also, what
happens if I drill al lthe way through the rock? This is pretty much
bedrock, so I think it goes down for quite a while. Also, what if
there is a quartz vein or something? I'm not sure if there is, but
perhaps I can't see it all... would this damage the drill or cause the
drill to explode in my face? Finally, what is the difference between
a drill and a "breaker unit"?
Thanks so much for you expert help, Ed!
On Apr 30, 6:02 pm, "Edward Hennessey"
If you were near me or another experienced operator, the more
holes you have
and the more precisely you need them positioned on irregular rock
you would balance against the cost of the rental, your
inexperience and mistakes
that may be troublesome to reverse. That said, this isn't brain
surgery. If you practice
on similar spare rock first, you should be able to handle it--or
know you can't.
First, you don't want to for your installation. You want
to drill a bit deeper than the posts you are going to put in.
posts would be nice. If you manage to poke through
with a long drill shaft, especially in harder rock, the drill
can get stuck or bent and the machine can toss you if you don't
it off when it binds and starts to overspeed.
This is pretty much
Granite tends not to have big, metamorphosed quartz veins and they
usually not terribly tough when present. The other kind of white
granitic vein would be
feldspathic and feldspar is a very soft mineral. My concern for
whether you could
do this was basically pointed at solid quartz. If you go to the
and get out a rock/mineral field identification guide, you can
figure out what rock type you have.
I'm not sure if there is, but
If your rental unit was gauging drill wear and you kept at some
resistant layer without progress, even with the carbide bit I
recommend, you might get
a wear charge. Otherwise, there is no danger.
Finally, what is the difference between
Some of the machines described are both jackhammers and drills.
The selector lever down near the chuck controls which function is
operative. Many times the lever won't fully seat in the proper
unless you grab onto the drill shaft and use it to turn the chuck
gear mechanism is aligned. Don't force the lever. When things
align it will go in easily. But if you don't get it properly
might get to buy the tool if the worst happens.
These combination tools average about 70-80 pounds. In rock like
you might have,
they will drill quickly and handling the machine in this
application is pretty
much a matter of being able to lift it.
Jackhammering with them requires more operator strength. If you're
shape, they won't push you around. Otherwise, they can be a bit
for some people. If you have been eating your Spinach, you might
able to use the jackhammer to do preliminary rock removal at
difficult angles to make the
pads to receive your posts. It depends on how precise your
placement needs to
be. Diamond sawing and grinding followed by a dimpled pilot hole
would be very clean. You could even put an outward bevel on the
pads to shed rain
after you make your dimpled hole with a star drill and small
Small diamond saws are available for grinders.
Lastly, if your holes are smaller--ask the rental guys what size
holes their machines will make-- there
are Swedish and Japanese gas-powered drills out there that will be
far easier to handle...and slower
on results. I've never used these smaller machines but Pionjar
made one and that is a good name.
You're welcome. Happy to help.
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.