Help drilling in concrete

[kelemvor]

Good day to you, ladies and germs. This weekend I'm going to be installing a handrail on my pool as I've got a disabled son who needs it. I've got the handrail and anchors, I'm looking for input on drilling the holes.

I need two holes 4" dia and 4" deep. Then brass anchors will be installed and back filled with epoxy per the instructions. The entire hole will be hidden under a cover.

I have a dewalt "hammer" drill that's not a real rotary hammer. Eats through cinder blocks easily enough based on past experience.

Would you buy a diamond bit (~$100) and have at it? Since there's an anchor going in, I don't think it's super critical that the holes are perfect, just that the anchors end up perfect. I could ensure that with some tiny shims or a jig.

Another option is to rent a proper core drill. Overkill power-wise, but it would ensure the holes are nice and straight. I don't like that it has to be bolted down so extra holes in the pool deck = yuck.

Should I go with the core drill or have at it with the regular one? Buy a diamond bit holesaw ($100) for 2 holes or try and have at it with a normal holesaw that I could throw away if I ruin (free - already have)?

 

[Wookie]

My dewalt hammer drill (20v) drilled holes in 50 year old concrete to install epoxy just fine, with a Home Depot concrete drill bit. Drilled about 6 each, 8 inches deep on a single 4 AH battery. 5/8” drill bit.

 

[broncobowsher]

Around here the standard thickness for concrete on a pool is only 4". When I did mine I upgraded to 6" concrete, that isn't very common. Not sure what local building practices are in your area. You might be in for a lot more work than you were expecting on that 4" deep hole.

 

[Akimbo]

You can rent 4" diamond coring bits from most rental shops. You may also need to rent the drill that fits it.

 

[lowviz]

Piece of cake!

Call your local rental store for availability of their water cooled core drill. You pick the core size you want, they mic it when you pick it up, you return it.

Edit:
Damn! Damn! Akimbo beat me...

 

[kelemvor]

Piece of cake!

Call your local rental store for availability of their water cooled core drill. You pick the core size you want, they mic it when you pick it up, you return it.

Home depot has all that stuff for an acceptable rental price. What's keeping me away is that the drill requires you to bolt it onto the concrete. I'll end up with at least one extra hole for the bolt that I'd like to avoid. It's a Hilti DD-200.

 

[lowviz]

Nah, rent a hand-held water-cooled drill and bit. Buy a bunch of cap blocks. The core drill will roll in the direction of its rotation and you can't physically overpower it. However, all you have to do is to get it started and then it puts up no fight at all.

Pile a bunch of blocks around the intended hole so that the drill rolls into a corner that puts it exactly where you want it. You can secure the blocks with all sorts of temporary heavy stuff. Try it on the lawn first, it will become obvious.

Edit:
If you drill a hole in masonry for utilities, then you have to FIRST insert a PVC pipe into the hole before your wires/water/air conditioning bundles go through. It is a building code thing.

Funny to see this thread, I recently drilled a hole into well over a foot of serious rock to install a convenient garden hose bib.



Piece of cake. Note that once a water-cooled core drill starts, it doesn't 'seek' an easier path, it just goes where you push it.