Drill bits

Soldato
Joined
31 May 2009
Posts
21,268
Bit of advice needed please.
Need to drill through a solid wall right above a door frame, some form of reinforced lintel is in place.
Normal 10mm masonary bit isn't doing the trick, very slow progress once through the plaster, not standard block being drilled into, door header.

What is the bit of choice for going through something reinforced?

- and if cabling is to go through, need to make a hole mayeb 15mm by 20mm, what sort of stopped spacers etc can one place over the cabling to tidy up the mess in the wall, or is it better to use filler and a spot of paint?
 
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I have no experience but i would imagine its not a recommended thing to do weakening a structurally significant part of a building. Also i would imagine the lintel is re-enforced with steel rod, might be a case of you have hit this.
 
Thanks.
Actually looks more like a concrete lintel rather than steel reinforced, I have been looking for any sign of metal on metal. Doesn't appear to be the case. Might need some form of diamond core bit, but wondering from folks who have done it.
 
Please drill through a different part of the wall. 15x20 is quite a big hole.

Someone else will know what stress concentrations mean in concrete. In a metal bar (I'm mechanical, not civil) a hole that size will do quite a lot of damage to the strength of the lintel.
 
The reason I was picking this area, is that a hole was already present where the previous occupant had made a right royal mess passing a telephoen cable through the wall.
I was seeking to expand the hole and make it neater, then close it back over after cabling.
Could move elsewhere but it'll leave 2 holes not one.
 
need to make a hole mayeb 15mm by 20mm
Holes are not rectangular, they are round ;)

Actually looks more like a concrete lintel rather than steel reinforced
All concrete lintels are reinforced (pre-stressed), otherwise they would snap like a twig, concrete only has strength in compression.

Best avoid drilling a lintel, it's a structural component.
 
Yes, what i should have said, is it looks like a concrete lintel rather than a piece of steel, as in an I-bar or similar steel lintel equivalent.

I'll run the hole elsewhere.
 
It will more than likely have steel reinforcing in it. Shine a torch into the hole and you should be able to tell. As said, if it does then don't drill any further. Probably best nbot to at all really.

You dont need any special drill to go through concrete. I drill through it all the time and just use normal tungsten carbide tipped bits. You do however need an SDS drill rather than a percussion drill.
 
The concrete used for lintels is a strong mix, so it's harder than say concrete blocks or patio slabs. If it's a modern lintel then it will also be pre-stressed and contain steel bars. Good luck going through it even with an sds drill :)

Best off just putting the hole elsewhere and making good the old hole with some filler and paint.
 
If you can avoid it, drill the hole elsewhere, if not then just get a decent drill and brand named bit... easy peasy... if you cant afford the above, drill a small hole first then work your way up to 10mm.
 
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