Cutting large hole through brick

I'm installing a range hood in my kitchen with a 7" round exhaust duct to the outside.

The exterior covering on my house is brick. I should also note that this is 1920's vintage brick and the joints, etc. are somewhat fragile. Any method of putting a hold through has to minimize impact that could knock loose more that I want to.

I previously had to put a smaller hole through for a bath fan exhaust. I used a hammer drill and drilled a series of 1/2" holes as close together as possible around the circumference of the hole. I then used a chisel to gently "connect the dots" to finish up the hole. It worked, but was very time consuming.

This method would also work for the 7" hole, but will take a lot longer with a lot more little holes to drill to cover the larger circumference.

Does anyone have a better way? I only have one hole to do, so I don't want to buy an expensive tool to do it. I probably would spend $30-50 to rent/buy a tool if necessary just to make it go faster.

Thanks,

Joel

You could probably rent a coring drill for this. I looks like a big hole saw, but with diamonds rather than teeth. Probably comes with a water attachment, so you'd want to do it from outside. It should make a nice clean, smooth hole, and in brick fast, too. One that will cut that big of a hole would likely be hard to handle, though.

Call a concrete coring company in your area for a quote...
They could have the hole cored in about 5 minutes... (once set up)
We consistantly have our coring sub doing 2" through 16" holes in poured concrete slabs and walls...
No problem....

IF you want a nice clean cut -get a masonry blade for your circ saw at the big box stores (about $20). Set the depth at ½ inch or less and score the bricks around the cut out. This spits out a LOT of dust-so be ready. I usually mark the cut out w/ blue painters tape and WEAR GOGLES. Then cut a center brick out by cutting the mortar w/ the saw-start out first pass at ½ inch or so then cut deeper. Once you are able to get a brick out-just chisel the bricks in toward the removed brick. It's really not that tough.

Richard