What's the best way to punch a 2" hole for a drain pipe through a cinder
I've researched a variety of suggestions from a hammer and a star drill, to
drilling a ring of small holes in a circle with a carbide bit to renting or
buying a diamond tipped core bit. What's the best way of doing it so as
NOT to crack the block?
Didn't rerad all the comments, but did anyone mention the moron that fired a
bullet through the wall for his cable? Killed his wife with a clean shot. I
wonder if the guy had any cable parts laying around?
I once pounded a 4" or 5" hole in 10" of solid concrete for a dryer vent. That
took a cold chisel, 24oz hammer, and a lot of beer. I didn't know i couldn't do
it....so I did it! My arms were like Jello after that.
You might try a 2" metal hole saw. They should be available at the box
stores and don't cost much. Here's a quick hit on a 2.5" hole bit for
As for 1/2" drill, should be no problem - they should run at a MUCH slower
speed than when drilling wood.
You could just poke an ugly opening, insert a 2.5" bit of PVC, then fill the
void up with cement.
I suspect that masonry is best attacked with "sterner stuff" - something
with a carbide or diamond tip. Thanks for the suggestion, though. I've
been able to find carbide tipped hole saws for not much more and I probably
wouldn't have to worry about it becoming too dull to even finish the job.
A hammer drill seems to be a better proposition for drilling through
masonry. Even the big 1" model is dirt cheap compared to some other
options. I might just use the masonry bits I have in the drill I have to
see what kind of progress I can make. The ring of small holes sounds like
the best way to go and the small bits are far cheaper than hole saws.
Well, I'm afraid that will probably be the end product no matter what
approach I take. Experience is gained proportional to the amount of
equipment or material ruined.
Thanks for the info. As long as I know they can be had at the WorkBench I'm
happy. Gonna try it with just the non-hammer 1/2" drill and a carbide bit
hole saw from the Borg and escalate from there . . .
Yes I did. But I own neither. I probably should have added that I would
prefer a solution that would work with a run of the mill, 1/2" AC power
drill that I do own.
Thanks for the suggestion.
I have used them all. FIrst of all, I am sure you don't really have a cinder
block wall. Many people wrongly call concrete blocks, cinder blocks which
were made from coal cinders. Making a hole in real cinder blocks is easy,
they are soft and can be punctured without much effort. Now concrete blocks
are different, they are hard and brittle.
You can use any method and it will not crack the block unless you use
extreme force to do the job. The easiest is to rent a large drill and bit
from your local big box store. The hardest part is to find out if you have
two core or three core blocks. New walls will be 2 core. Whatever method you
use will work best if you miss the web in the block. You may have to do some
small hole drilling to find the core and web. Old blocks with 3 cores are
easy to work if you drill through the center and hit the center core. Newer
blocks will only have two cores and you will hit the web if you drill in the
middle, so you need to drill 1/3 of the way from the end. The year that
manufacturers changed to two core blocks will vary according to when they
changed machines and moulds.
Yes, vertical re-bars mortared in the cores, sometimes from footing up to
the sill plate, can cause problems. You may want to check with a metal
detector to see if you can find any. Horizontal reinforcement would most
likely be in the mortar joint, so avoid penetrating in this area.
A good idea, but I'm betting there's no rebar because everything was in
short supply in 1942. They skipped on things like putting building paper
between the subfloors so the open basement ceiling rains down plaster dust
on the stuff below. Such an easy thing to have done right during
construction and now such a bitch to remediate.
Well, if my previous experience of trying to drill through to the basement
and managing to hit a discarded hammer head inside the wall cavity is any
indication, I'll run into something nasty. Acutually, now that I am reading
through this, I realize there's a dryer duct installed that I can pull that
should give me a better idea of what I am facing. Thanks for the input.
Excellent points. The worry about 'crackign the block' is no biggee.
The likely hood of making a tight fitting 2" hole without using a core
drill is zero so it will have to be patched in any case. I have done
the BFH route and patched the remains later, used a 3/8" hammer drill
and small concrete bit and probably a few other methods. If I ever
have to do it again it will be 'rent a real electric hammer and decent
bit, drill a ring of holes and knock out with hammer' Of course being
careful to miss the web.
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