How can I increase the size of a hole in a cinder block?

Question

My dryer vent kept clogging and when I traced the ouside vent the pipe going through is only about 2.5 to 3 inches in diameter. my new vent pipe is 4 inches. How can I make the hole bigger without destroying the block

Answer 1

With a chisel and a hammer!Wear eye protection it will be messy.

Answer 2

There are a few ways. The hardest way is to just use your regular drill bit and drill holes all around then new opening size you need and then knock out the pieces with a hammer.
This will of course kill that bit, but it's way cheaper than the alternative.

Buy a masonry bit and do the same.

Or go Cadillac and buy a large (If it's made) round 4" cup style masonry bit. Then you go to the max allowed by the cup and break off the drilled section and then go at it again.

Any of these you need an elec. drill, not battery or you'll be recharging until you cuss a blue streak.

I did it the cheapo way. It takes time but no extra money.