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.


"Greg" wrote in message
news:b7x1k.6244$C12.3397@pd7urf3no...
Also makes a difference if you have re-bar on every 3rd coarse and blocks
filled with concrete like mine are

"EXT" wrote in message
ews.com...
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.

"Robert Green" wrote in message
...
What's the best way to punch a 2" hole for a drain pipe through a cinder
block wall?

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?

--
Bobby G.