Minor D-I-Y jobs that according to others "should just take you five
minutes" have a tendency to turn into sagas.

Drill four holes in the wall to put up a hat rack.

Said wall is concrete. HARD concrete. 850 watt SDS drill borrowed for
the purpose with new bit makes pretty much zero impression, and
wnaders all over the shop. Ordinary hammer drill with bullet tip drill
bit does the job eventually, after drilling small (4 mm) guide hole
with standard masonry tip. Each hole probably took 20-30 minutes of
drilling, which won't have endeared me to the neighbours.

Had to drill eight holes to put up cupboards a couple of months ago:
Battery powered SDS borrowed for the job ran out of puff after a hole
and a half, so borrowed a BIG DeWalt SDS which did those holes like
the wall were butter. Unfortunately, couldn't borrow it again (lender
was away on hols), so tried to use a standard SDS - which made no
impression. Given the battery powered one worked while it had charge,
how come the standard wired one didn't?

What on earth was this concrete made of?

(Oh, and minor rant: woodscrews that snap half way into the job,
leaving me the job of taking the pieces apart held together by a now
headless screw, so I can replace the screw. Screwdriver bits made of
butter. This weekend was not a good weekend).

In article <165c28c5-e259-4273-8cba-(E-Mail Removed)
..com>, Sidney Endon-Lee <(E-Mail Removed)> scribeth thus
>Minor D-I-Y jobs that according to others "should just take you five
>minutes" have a tendency to turn into sagas.
>
>Drill four holes in the wall to put up a hat rack.
>
>Said wall is concrete. HARD concrete. 850 watt SDS drill borrowed for
>the purpose with new bit makes pretty much zero impression, and
>wnaders all over the shop. Ordinary hammer drill with bullet tip drill
>bit does the job eventually, after drilling small (4 mm) guide hole
>with standard masonry tip. Each hole probably took 20-30 minutes of
>drilling, which won't have endeared me to the neighbours.
>
>Had to drill eight holes to put up cupboards a couple of months ago:
>Battery powered SDS borrowed for the job ran out of puff after a hole
>and a half, so borrowed a BIG DeWalt SDS which did those holes like
>the wall were butter. Unfortunately, couldn't borrow it again (lender
>was away on hols),


Advice.. Invest in a good SDS drill you won't look back in anger..

Haven't met any concrete that my Makita can't handle as yet)..

>so tried to use a standard SDS - which made no
>impression. Given the battery powered one worked while it had charge,
>how come the standard wired one didn't?
>
>What on earth was this concrete made of?
>
>(Oh, and minor rant: woodscrews that snap half way into the job,
>leaving me the job of taking the pieces apart held together by a now
>headless screw, so I can replace the screw. Screwdriver bits made of
>butter. This weekend was not a good weekend).

Buy better quality ones then;!...
--
Tony Sayer

There must be something unusual about your concrete, or some of these
drills/drill-bits are particularly naff.

IME my bosch, with even a quite worn bit, will put a 20mm bit into
concrete where flint has been used as aggregate.

What do you know about the concrete, age? composition? used for some
special purpose? (e.g. your house is a converted nuclear bunker)

Brands of drill/drill-bit that were good/bad?

On Jan 25, 8:48 am, Sidney Endon-Lee <unope...@mail.com> wrote:
> Minor D-I-Y jobs that according to others "should just take you five
> minutes" have a tendency to turn into sagas.
>
> Drill four holes in the wall to put up a hat rack.
>
> Said wall is concrete. HARD concrete. 850 watt SDS drill borrowed for
> the purpose with new bit makes pretty much zero impression, and
> wnaders all over the shop. Ordinary hammer drill with bullet tip drill
> bit does the job eventually, after drilling small (4 mm) guide hole
> with standard masonry tip. Each hole probably took 20-30 minutes of
> drilling, which won't have endeared me to the neighbours.
>
> Had to drill eight holes to put up cupboards a couple of months ago:
> Battery powered SDS borrowed for the job ran out of puff after a hole
> and a half, so borrowed a BIG DeWalt SDS which did those holes like
> the wall were butter. Unfortunately, couldn't borrow it again (lender
> was away on hols), so tried to use a standard SDS - which made no
> impression. Given the battery powered one worked while it had charge,
> how come the standard wired one didn't?

was it shagged? either the hammer mechanism or the chuck could have
been "well used"/abused by previous users - levering whilst chiselling
shags chucks, no grease on the bits means the mechanisms wear quicker
etc etc

Even a cheapo new SDS is worth your while - my £30 jobby still does
the (occasional) business :>)

A mate bought a Dewalt small SDS drill - I couldn't believe it could
claim to be SDS ... it was sh1te...about the only thing SDS about it
was the chuck!

Cheers
JimK

> A mate bought a Dewalt small SDS drill - I couldn't believe it could
> claim to be SDS ... it was sh1te...about the only thing SDS about it
> was the chuck!

I saw those heavily discounted at Interbuild last year, nicely compact
for awkward access (but my rule is not to buy unless I have an
immediate use).

I'm glad I didn't!

(E-Mail Removed) wrote:
> There must be something unusual about your concrete, or some of these
> drills/drill-bits are particularly naff.
>
> IME my bosch, with even a quite worn bit, will put a 20mm bit into
> concrete where flint has been used as aggregate.
>
> What do you know about the concrete, age? composition? used for some
> special purpose? (e.g. your house is a converted nuclear bunker)
>
> Brands of drill/drill-bit that were good/bad?

Concrete is around 25 years old. No idea about composition, other than
it appears quite fine grained, and it's HARD. I don't live in a
nuclear bunker.
The particular wall I was drilling into was around the stairwell/
communal entrance hall - it's a 5 storey block of flats.

Drill bits:
Black & Decker Piranha 6mm diameter SDS-Plus (New)
Unknown brand 6mm SDS bit, supplied with borrowed drill - (Used) -
Useless.
Black & Decker Piranha 6mm "Hi Tech" Bullet (Lightly used until
now. :-)
Black & Decker Masonry 4mm Bullet "Pilot Point" (New)

The SDS got nowhere. Well, not completely true, 10 minutes drilling
gave me about 5 mm depth into the concrete, but no further. The drill
(not mine) is probably not working properly, I guess.
Hammer drill with the 6mm bullet tip worked slowly.
One hole was difficult, as the SDS had wandered. I finally succeeded
by drilling a pilot with a 4 mm masonry, then enlarging with the 6mm
hammer drill.

I will need to drill some more holes. I'm reluctant to buy a random
SDS if it isn't guaranteed to perform.

tony sayer wrote:
> In article <165c28c5-e259-4273-8cba-(E-Mail Removed)
> .com>, Sidney Endon-Lee <(E-Mail Removed)> scribeth thus

> >(Oh, and minor rant: woodscrews that snap half way into the job,
> >leaving me the job of taking the pieces apart held together by a now
> >headless screw, so I can replace the screw. Screwdriver bits made of
> >butter. This weekend was not a good weekend).
>
> Buy better quality ones then;!...

It shows price is no indication of quality. They were not cheap -
local 'shed' rip-off. I've half a mind to complain, as this is not the
first to lose it's head. But it's a learning experience: moral is, use
pilot holes when it is important.

Cheers,

Sid

On Mon, 25 Jan 2010 00:48:22 -0800 (PST), Sidney Endon-Lee
<(E-Mail Removed)> wrote:

>Minor D-I-Y jobs that according to others "should just take you five
>minutes" have a tendency to turn into sagas.
>
>Drill four holes in the wall to put up a hat rack.
>
>Said wall is concrete. HARD concrete. 850 watt SDS drill borrowed for
>the purpose with new bit makes pretty much zero impression, and
>wnaders all over the shop. Ordinary hammer drill with bullet tip drill
>bit does the job eventually, after drilling small (4 mm) guide hole
>with standard masonry tip. Each hole probably took 20-30 minutes of
>drilling, which won't have endeared me to the neighbours.
>
>Had to drill eight holes to put up cupboards a couple of months ago:
>Battery powered SDS borrowed for the job ran out of puff after a hole
>and a half, so borrowed a BIG DeWalt SDS which did those holes like
>the wall were butter. Unfortunately, couldn't borrow it again (lender
>was away on hols), so tried to use a standard SDS - which made no
>impression. Given the battery powered one worked while it had charge,
>how come the standard wired one didn't?
>
>What on earth was this concrete made of?


It's all to do with the choice of coarse aggregate.

Concrete is made up of cement paste (cement and water) which coats the
aggregate and glues it all together. The cement paste itself isn't
particularly strong. The strength comes from the coarse aggregate and
how it interlocks within itself, with the gaps between pieces of
coarse aggregate filled by fine aggregate (sand) and cement paste.

That's how concrete works - the combination of the strength of the
aggregate and its ability to interlock gives concrete its overall
strength; the cement paste is a weaker link that holds it all
together.

The hardness of the coarse aggregate in your concrete is probably what
is making the job so difficult.

On Mon, 25 Jan 2010 01:22:11 -0800 (PST), (E-Mail Removed) wrote:

> There must be something unusual about your concrete, or some of these
> drills/drill-bits are particularly naff.

Agreed, possibly technique as well. You don't lean on an SDS drill
like you do a hammer drill, apply pressure but let the drill do the
work and remember to pull back to clear the dust from the hole. SDS
bits have more metal in 'em than a masonary drill so less room for
the dust.

> IME my bosch, with even a quite worn bit, will put a 20mm bit into
> concrete where flint has been used as aggregate.

<cough> I've put a 20mm dia hole through 12"+ of stone with my Bosch
rotating the wrong way, I did wonder why it seemed to be making
harder work of it than normal.

--
Cheers
Dave.

Dave Liquorice wrote:
> On Mon, 25 Jan 2010 01:22:11 -0800 (PST), (E-Mail Removed) wrote:
>
> > There must be something unusual about your concrete, or some of these
> > drills/drill-bits are particularly naff.
>
> Agreed, possibly technique as well. You don't lean on an SDS drill
> like you do a hammer drill, apply pressure but let the drill do the
> work and remember to pull back to clear the dust from the hole. SDS
> bits have more metal in 'em than a masonary drill so less room for
> the dust.
>
> > IME my bosch, with even a quite worn bit, will put a 20mm bit into
> > concrete where flint has been used as aggregate.
>
> <cough> I've put a 20mm dia hole through 12"+ of stone with my Bosch
> rotating the wrong way, I did wonder why it seemed to be making
> harder work of it than normal.
>
Thanks Dave (and thanks for the confession). I did all that - if I let
the drill do the work, nothing happened. Relatively firm pressure gave
_very_ slow progress. It leads me to the conclusion that the drill is
worn out (which the owner won't like) - it's possible the owner abused
it in some way.

The drill bits could be naff as well.

I would not be surprised if the aggregate is granite.