I am installing 3/4" hardwood in my family room. The raised brick fireplace hearth is curved which complicates any framing or trim piece option so I am looking at undercutting with a Crain 812 and diamond blade.

How deep do you usually cut in, and how far should the wood extend into the groove?

And how tall should the upper cut be? I imagine you want to go a little higher than the wood plus roofing paper. How much higher?

Thanks

Everyone probably has their way that works for them.

Height: I dont like to see even a hint of gap on top of the wood, yet not tight, so there's a problem sliding under. Usually adjust for height, and dial it in ,running the blade slightly into some drywall , at the wall, to arrive at the height adjustment.
Depth: If 1/2" expansion is called for...I will cut 3/4" depth and go under 1/4". Depending how deep the "grout rake" is on the stone or brick, I may cut deeper.

I go in about an inch and a half, cut top first then bottom, then snap off whats left with a small pry bar. Gotta have that thing hooked up to a shop vac. I like it tight as well but if theres a thick layer of mud under brick or stone it falls out a lot so just grout caulk it after wards.

I cant resist .... 1 1/2" ??!! What are you hiding in there ??!! LOL

Darn straight about the vacuum, that will dust a house in a heart beat.

Bodies! lol

Gets me into the corners better.