Drilling into VERY HARD concrete

[XrayDave]

Hellofolks

Posted this in the "Building" section - don't know if 'Tools & MAterials" is more appropriate. Anyhow...

Trying to drill a 6mm dia 30mm deep hole (for a wall plug) into a concrete lintel - and not having much joy to be honest.

I've managed to completely drill one hole (out of six) and am two-thirds of the way into the second hole.

I'm using a DeWalt drill on speed 3 with hammer action and using a Bosch masonry drill - but it is taking AGES.

I drill for 15-20 sec, then remover the drill and coolt he tip in some water, before having another go. After 2 or 3 goes, I swap to a second drill bit (to allow the first to completely cool down).

Are there any better drill bits out there?

Would these also do the job on my bricks - which are also bl**dy hard - a kind of engineering brick?

I don't want to have to go down the SDS drill & bit route as I only have another four-and-a-half holes to go.

Cheers

XRD

 

[opps]

You need a SDS drill.

Alternatively you might be able to use diamond core bits but you will need to snap the cores as you work away, and a 7mm diamond bit will probably only go 35(?)mm deep.

Oh, and if you hit a reinforcing bar, that might shear the head off a regular SDS bit. I use the Makita Nemesis 4 flute SDS bits in those situations.

 

[cdbe]

If my DeWalt topish of the range 18v (DCD996) doesn't do it and I don't want to SDS then my trusty old Bosch GSB20 normally does the trick - I guess it's the extra power (700w) and (I think) faster speed but stick the same drill bit in and it screams through.

Otherwise try a branded 3mm bit to make a pilot hole.

 

[kingandy2nd]

6mm diameter hole 30 mm deep?

You sure your hammer action is working? Is it a new masonry drill bit??

Post a picture of your drill and drill bit.

Sds?!? Come on guys. Even a ryobi cordless drill should manage that…

 

[foxhole]

Hellofolks

Posted this in the "Building" section - don't know if 'Tools & MAterials" is more appropriate. Anyhow...

Trying to drill a 6mm dia 30mm deep hole (for a wall plug) into a concrete lintel - and not having much joy to be honest.

I've managed to completely drill one hole (out of six) and am two-thirds of the way into the second hole.

I'm using a DeWalt drill on speed 3 with hammer action and using a Bosch masonry drill - but it is taking AGES.

I drill for 15-20 sec, then remover the drill and coolt he tip in some water, before having another go. After 2 or 3 goes, I swap to a second drill bit (to allow the first to completely cool down).

Are there any better drill bits out there?

Would these also do the job on my bricks - which are also bl**dy hard - a kind of engineering brick?

I don't want to have to go down the SDS drill & bit route as I only have another four-and-a-half holes to go.

Cheers

XRD

Try a 4-5 mm bit

 

[Notch7]

6mm diameter hole 30 mm deep?

You sure your hammer action is working? Is it a new masonry drill bit??

Post a picture of your drill and drill bit.

Sds?!? Come on guys. Even a ryobi cordless drill should manage that…

I dunno, Ive had to resort to an SDS for lintels, they are bl@@dy hard

 

[Notch7]

I don't want to have to go down the SDS drill & bit route as I only have another four-and-a-half holes to go.

you could try Dewalt extreme masonry bits

start with 4mm then 5mm then 6mm

but to be honest I tried that on lintels last year fitting some blinds and I gave up and got the SDS drill out -which went through dead easy

 

[aveatry]

Try this one and start with a 3 or 4mm first. https://www.toolstation.com/bosch-expert-cyl-9-multi-construction-tct-drill-bit/p21223
I have been very impressed with it

 

[noseall]

SDS - always. Just stay away from the edges.

 

[XrayDave]

6mm diameter hole 30 mm deep?

You sure your hammer action is working? Is it a new masonry drill bit??

Post a picture of your drill and drill bit.

Sds?!? Come on guys. Even a ryobi cordless drill should manage that…

Not with my bricks or lintel it wouldn't!

I appreciate it when folks take the time to reply, but honestly, I am NOT going to buy an SDS drill just to drill 4-and-a-half holes for wall plugs. Hence what I said in my OP.

The drill is a DeWalt DCD995 with fully-charged 4Ah battery.

No idea what brand the masonry drill bit is - but looks okay (pix to follow). I am using a smaller (and sharper 4.5mm as a pilot).

Have ordered 3x Bosch Professional Exper CYL-9 bits fromAmazon and a couple of DeWalt EXTREME 2 DT6676-XJ bits to pick up from Screwfix tomorrow. I'll see how they compare against each other.

I'm not bothered about having "spares" as given how hard our bricks are (and that's "damned hard") they won't go to waste!

XRD

 

[aveatry]

That drill bit looks blunt and knackered to me. You will love the cyl-9 bosch ones.

 

[johnny2007]

Ask your neighbour for an sds.
My makita sds is shared between the whole neighbourhood...

 

[XrayDave]

It looked like that after the first hole!

I'm not surprised that it isn't making much progress to be honest!

Dave

 

[aveatry]

Have ordered 3x Bosch Professional Exper CYL-9 bits fromAmazon and a couple of DeWalt EXTREME 2 DT6676-XJ bits to pick up from Screwfix tomorrow. I'll see how they compare against each other.

Look forward to your "drill" off report with these two.
Interestingly I recently brought a new DEwalt and noticed that its hammer function is sort of shorter and faster which made it better at drilling than my older Dewalt.

 

[kingandy2nd]

Dewalt extreme drill bits are my preferred drill bits.

Can we see the top of your drill to see what settings you’ve got it on please?

I lent my mate my cordless drill and new drill bits so he could hang a hanging basket - got a call saying how ****e my drill was and the he couldn’t make a hole in his brick wall with it…he just didn’t realise that there was a setting for the hammer action (which it wasn’t on).