Hello,

I tried to drill a hole through a 500mm concrete wall yesterday. I was
hoping to put a 15mm copper pipe through to an outdoor tap (you may
remember my other thread about the old pipe freezing and bursting).

I was unsuccessful. I used an sds drill and I got through the wall
quick enough but although I (thought I) held the drill level, the exit
hole and the entry hole were at two different heights and passing a
pipe through was impossible.

Now that I know from the "one metre drill bits at Aldi" thread that
these bits are flexible, is it possible that the bit deflected inside
the wall?

How can I prevent this in the future? I drilled from one side straight
through. Should I have carefully marked each side and drilled from
each side, hopefully meeting halfway?

For drilling though brick I have used a 16mm bit for 15mm pipe in the
past. Do I need to use something bigger than 16mm in concrete to allow
for it not being straight?

I was using a 6kg Titan drill I got from Screwfix some time ago.
Despite being a budget model it has served me well. I had a Bosch
drill bit in it. I had not used the drill bit before and I won't be
using it again as the end broke. I had expected better longevity from
a branded bit. Are the clutches on sds drills like those on cars, i.e.
do they wear out eventually? I ask because mine worked once or twice
yesterday ;(

Thanks,
Stephen.