|
Posted by Edward Hennessey on May 1, 2008, 7:32 pm
> On Apr 30, 6:02 pm, "Edward Hennessey"
>> nicklang907 wrote:
>> > Hi,
>>
>> > 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?
>>
>> NL:
>>
>> Call your rental yards. Ask for Cobra, Berema or Pionjar
>> gasoline-powered drills.
>> 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
>> adjustments.
>> If you get a combination breaker/drill unit, be clear on the
>> selector control
>> 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!
NL:
You sure you got the right Ed?
>
> Your response really led me in the right direction. I have a
> few more
> questions.
>
> Is this a job for someone unexperienced like me? That is,
> should only
> people who really know what they are doing try this?
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
is something
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.
Also, what
> happens if I drill al lthe way through the rock?
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.
Stainless
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
shut
it off when it binds and starts to overspeed.
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?
Granite tends not to have big, metamorphosed quartz veins and they
are
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
library
and get out a rock/mineral field identification guide, you can
probably
figure out what rock type you have.
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?
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
> a drill and a "breaker unit"?
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
position
unless you grab onto the drill shaft and use it to turn the chuck
until the
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
seated, you
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
in
shape, they won't push you around. Otherwise, they can be a bit
vigorous
for some people. If you have been eating your Spinach, you might
even be
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
sledge.
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.
> Thanks so much for you expert help, Ed!
>
You're welcome. Happy to help.
Regards,
Edward Hennessey
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap