Core-Drilling Through Exterior Brick Wall

[DSmedley]

Hi, I bought a cheap 2" core drill bit from Vevor because I need to drill weep holes in an exterior brick retaining wall. It just came in and I found the pilot (centering) bit is off-center but the bit isn't bent. I haven't tried it yet because I'm worried that it might be dangerous. I assume it will wobble. My question is: is it dangerous? Should I try it anyway?

 

[sparky 1971]

The bit is off center because it's bent. It's probably going to wobble so bad that when the core starts in, you are going to bind up. If the drill doesn't have a clutch, you could get tossed around or break the pilot bit off in the wall. If it's like my core bits, you use the pilot to get the core bit started, then take the pilot bit off and finish the hole. I wouldn't have a problem using that style.

 

[kyrbz]

You might remove the centering bit and roll it on a flat surface to get a feel of how bad or if it's bent. It's kind of a long bit and additionally might just be not correctly set with the set screws? I also might mention that often the back side of a masonry hole blows out pretty bad so drill from the good side. If I need both sides of hole to look good, I'll drill a pilot hole all the way through and then use the core bit to drill half way through from both sides. That will give you a clean hole on both sides of the wall. I've also used a plywood jig clamped or screwed to a wall with a hole corresponding to the core bit size to keep the core bit from skating around.

 

[dutchgray]

You might remove the centering bit and roll it on a flat surface to get a feel of how bad or if it's bent. It's kind of a long bit and additionally might just be not correctly set with the set screws? I also might mention that often the back side of a masonry hole blows out pretty bad so drill from the good side. If I need both sides of hole to look good, I'll drill a pilot hole all the way through and then use the core bit to drill half way through from both sides. That will give you a clean hole on both sides of the wall. I've also used a plywood jig clamped or screwed to a wall with a hole corresponding to the core bit size to keep the core bit from skating around.

I always drill through with a standard SDS bit first to check location then use the core drill, rotation only those diamond segment ones are not meant for hammer use, you should get almost perfect clean exit holes with a core drill.

All the ones I have used the pilot drill or guide rod is attached with the very old "A" taper system, which almost never holds on for long.

 

[dutchgray]

To add I have done all kinds of sketchy stuff to get one started without using a pilot, holding it between my boots, using a plywood template, evenhalf burying one in a mound of sand.

 

[DSmedley]

Thank you everybody! I wrote Vevor hoping to get another one, but in the meantime I like the template idea without the pilot bit. Think I can make a jig with some 2x4s and brace it well, or should it be plywood? I need to make 6 weep holes (2 rows, upper and lower) so I'm hoping not to screw them into the mortar each time. I suppose I can cut both holes (top and bottom) in a 3'x4' piece of 5/8 ply and space them to brace against the floor. What do you think? Btw, thanks for the advice on how to use the core bit. It's my first time, that's why I bought it cheap, ha ha. Thanks again.

 

[The Cobbler]

My 30 lb Bosch demo hammer/ drill wouldn't care too much that the center bit was off center. it would make the cut kerf wider . once I was in deep enough I would take out the center bit & continue on.
but good to call vevor & see what they will do . I suspect the will make good

 

[dutchgray]

Thank you everybody! I wrote Vevor hoping to get another one, but in the meantime I like the template idea without the pilot bit. Think I can make a jig with some 2x4s and brace it well, or should it be plywood? I need to make 6 weep holes (2 rows, upper and lower) so I'm hoping not to screw them into the mortar each time. I suppose I can cut both holes (top and bottom) in a 3'x4' piece of 5/8 ply and space them to brace against the floor. What do you think? Btw, thanks for the advice on how to use the core bit. It's my first time, that's why I bought it cheap, ha ha. Thanks again.

That would be fine, once you get the core started, like a good 1/8" depth in you can continue without the guide.

I did a 5" through a solid 4 course thick hard brick wall this week, took all afternoon to get through.

 

[tarbellb]

Likely it was machined at the connection off angle. Personally I would likely just torque to center and give it a go. This is a relatively crude operation to begin with

Vevor is the International version of HF, you get what you get and its typically cheap for a reason.

 

[Al Borland]

2" I usually freehand. No pilot needed Tip the drill a little so the bottom edge stars first and then bring it up to level.

 

[dscheidt]

That would be fine, once you get the core started, like a good 1/8" depth in you can continue without the guide.

I did a 5" through a solid 4 course thick hard brick wall this week, took all afternoon to get through.

With a proper core drill, or an sds ? I did a 4" in my four wythe wall for a split. Spent more time setting up the core drill I rented than drilling the hole. Not an engineering brick, but still that seems slow.

 

[dutchgray]

With a proper core drill, or an sds ? I did a 4" in my four wythe wall for a split. Spent more time setting up the core drill I rented than drilling the hole. Not an engineering brick, but still that seems slow.

With a hand held Makita core drill, not a drilling rig, which would make it go much faster as you can put decent pressure on then.
The bricks are from a long defunct local brick maker, their standard bricks meet engineering brick spec, was below ground level so was wet which never helps with dry diamond cores.

If you could rent the rigs where I am we would, but we don't have the need often enough to justify the cost of buying one, if we ever have a lot to do in one go you can a drilling company in for a day.

 

[Brente]

I do lots of this stuff you don't need a centering bit you just need to pay attention while you start, once started is all gravy. PS us a hammer drill if you have one makes it far easier