How to drill a 4 inch hole in concrete

The walls at our new place are 6 inch thick concrete (it's an old Naval base) and we needed a few holes for vents. I've hammer-drilled through concrete to sink anchors, but a 4 inch diameter hole is a little intimidating -- until you have the right tool. Here's a few pictures of the right tool. I only watched, so I don't know the finer details, but I thought people would appreciate just seeing the tool. The work flow went something like this: 1) hammer-drill and sink anchor to attach machine to wall 2) turn on machine; insert earplugs 3) wait It took quite a while, and that drilling noise reverberated throughout the whole place!

Picture of How to drill a 4 inch hole in concrete
sort by: active | newest | oldest
jjhale2 years ago

Looks like you can rent this from Home Depot

lemonie10 years ago
I know someone who was given £60 by his mum to hire a concrete-drilling device. He never did and spent the £60.... L
swoodall1210 years ago
I'm trying to secure a frame machine in concrete with a stand that requires a 4" diameter hole. I can't find a concrete saw that will make the cut. Where did you purchase/rent the saw you used? Any suggestions would be greatly appreciated as my husband is killing himself using this frame machine without the anchors.
ewilhelm (author)  swoodall1210 years ago
The one in the picture is being used by a contractor. I don't actually know where they purchased it.
crapflinger10 years ago
that thing had to sound like it was being powerd by all the evil, hatered, and crying clowns on the planet!...could be used for an instructable "How to turn your car into a 'swiss-cheese-mobile'"
trebuchet0310 years ago
That's one ginormous drill bit :D My parents installed a child safety fence around their pool -- a similar tool was used to drill the 1" holes for the fence posts. I don't remember the material for the bit -- bit it too was water cooled :)
The probably use the water from the pool :P

Agreed, that is one huge bit.
Do you know what the size is where they don't use a giant drill bit anymore, and just cut out the circle?

"I said 4 CENTIMETERS!" *sigh*