Drilling a new drain hole in floor

[lunct]

A room with 5 inches of slab has no floor drain. A 2 inches diameter drain is needed. Has anyone tried successfully drilling the hole with a 1/3 inch drilling machine bit.. I mean you can't make a perfect hole where the pvc tube could be inserted.. can you just put sealant on the perimeter if it's rough and nonuniform cut?

What technique did you use to put a new 2 inch diameter drain in 5 inches of slab?

Thank you.

 

[XR250]

I assume you mean to drill a bunch of 3/8"Ø holes around the 2"Ø perimeter? I have done this successfully but it was not fun. Had to use the chipping hammer bit in my hammer drill and a sledge to finish it off.
You could probably rent a core drilling machine pretty cheaply instead. My local steel guy has one he uses for handrails, and if I had known, I would of hit him up.

 

[kingnero]

If a core drill is not available, your way will work just as good but it'll take a bit longer. Seal with PU foam or similar.

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[MotorCity]

"What technique did you use to put a new 2 inch diameter drain in 5 inches of slab?"

Just buy a 2" concrete coring bit and do it right. I assume this is for an elevated slab?

 

[JedClampett]

Or you could call the "Concrete Coring Guys" or whatever they're called in your neighborhood and get it done with someone else's equipment.

 

[dhengr]

Lunct:
You might want to core drill .5 - .75" deep with a bit slightly larger than the drain cover so it can be set flush with the floor. Then drill the rest of the way with a core bit large enough to fit the O.D. of the drain pipe. The O.D. of your 2" pipe may be larger than 2" in dia. core bit. Then you set the drain in grout or quick-set, to be flush with the floor.

 

[lunct]

I assume you mean to drill a bunch of 3/8"Ø holes around the 2"Ø perimeter? I have done this successfully but it was not fun. Had to use the chipping hammer bit in my hammer drill and a sledge to finish it off.
You could probably rent a core drilling machine pretty cheaply instead. My local steel guy has one he uses for handrails, and if I had known, I would of hit him up.

My only option is to drill a bunch of 3/8" holes around the 2" perimeter. I can't use core drilling machine and I can't even use hammer drill.. just ordinary drill.. you mean it's not possible using ordinary drill (with hammer function)?

 

[hokie66]

The only way to find out is to try it. The worst thing you can do is to ruin your drill. Expect to wear out a few bits. But that depends on how hard the concrete is.

You must be able to buy a hammer drill somewhere. I have been in some third world places, but there is always a hardware store selling Bosch or Makita tools.

 

[lunct]

problem with hammer drill is it can vibrate the floor or concrete gutter such that it can cause micro molecular detachment between the floor or gutter to the support connecting them. Concrete bond can be attachement by any strong vibrations... that's why I don't want to use a hammer drill or chisel...

 

[hokie66]

That is an unrealistic precaution. Who told you that?

 

[mjr6550]

I often use a rotary hammer drill. Not much vibration. You could buy a cheap core bit just to get a clean cut at the surface and then drill the rest.

 

[Ingenuity]

...one of the strangest thing I ever saw was on a island in Micronesia about 2 decades ago. Concrete framed building with RC walls. GC cast the door opening too narrow so 8+" of concrete had to removed from one side of the 6'6" height. Accomplished via a PVC tube with a hardened nail through one end, and a hammer (made from #6 rebar 'handle' welded to a #8 rebar 'head'), and one very, very patient, diligent laborer who chipped away...and remarkably plumb and flush. He did what his boss told him to do.

Back to the OP's question: For such a small dia hole AND access to a percussion chipping tool, consider the use of a dry-core bit:

For a 5" thick slab (and assuming you don't hit rebar) such a hole would take less than 15 minutes - do it after hours to minimize noise/vibration.

Or wet core it - diamond wet-coring for a 2" hole has minimal (nil?) vibration and very quick with a correctly selected diamond matrix.

 

[XR250]

Sounds like this guy only has access to the cheap high frequency buzzing hammer function on a standard dual purpose drill (not a rotary hammer drill). They work fine on masonry or small holes in concrete, but it will take awhile.
Good luck!