Using this 4.5" diamond core bit, I was able to core through 5-6" of 50 year-old concrete in a retaining wall in about 20 minutes. I did run a garden hose to slowly spray into the hole/gaps for wet-drilling, which seemed to help quite a bit. NOTE: this 5/8"-11 bit does NOT directly fit the Vevor Diamond Core Drill that I bought it with, which had a water valve built in, and that was a bummer. So, be sure if you're using this bit, and also buy their common Vevor 1800W Diamond Core Drill (which has a 1 1/4"-7 output shaft), that you also buy the proper adapter, which can be found on Amazon for about $30. The Amazon title of the one I bought is: "Shaft Adapter for Core Drill, 1 1/4"-7 Female to 5/8"-11 Male, for Use with Diamond Core Bits" That still won't allow you to use the built-in water-jet of that drill, but perhaps you can just setup a hose to spray into the hole like I did. Also Note: You will not find a 5/8"-11 adapter that has threads long-enough to fit deep enough into this bit to work properly with a strong regular mixing drill or SDS drill (don't use hammer function though) at Home Depot or Lowes, though those adapters can be found on Amazon as well for $10-$15, but be sure if you go that route that you get one with more than at least 5 rows / 1cm of thread or more so it sets deep-enough into the bit to handle the torque needed. (I did find a 5/8-11 - drill adapter at lowes in a kit, but it only allowed maybe 2 rows of threads to insert, and it stripped those threads out after 5 minutes of drilling (as I predicted, but had to try), before I ordered a better option off Amazon). Still, despite the adaption issues, once those were solved and the right adapter was bought, this bit worked great. Oh, last note- I'm just a regular homeowner with DIY skills and this was my first time coring a large hole like this. I did a lot searching online as to whether 4.5" would be large-enough for 4" schedule 40 PVC pipe, and most sites recommended a 5" bit, but I'm very glad I used this 4.5" bit instead, because the hole size was absolutely perfect, and required no filler like what would have been required had I drilled a 5" hole.

My original review was pretty harsh. I am updating it because I figured out how to get it to work.I drilled a large pilot hole with a different bit. Then I cut a hole into an old piece of wood to use as a guide and screwed it into the wall. I got through two layeres of brick fairly easily.The cutting disc it came with was pretty good.

It does its job if you have enough power behind it.Cuts a nice round hole as a cylindrical cutter should. I was coring in hard south Texas caliche. It was rough going with an old SDS drill. The SDS MAX is the MINIMUM you should use with this. But it does cut, I drilled 3 holes so far.

Homeowner/DIY tips: We are installing a 8" exhaust vent through our exterior brick house. Here are so things we learned along the way.1. The 8" core bit is heavy and you need something like a joist/stud drill that has enough torque/power to make this work.2. A heavy duty hammer drill/SDS demolition/rotary hammer will make drilling easier but these fancy drills are not required.3. periodically wet the core bit in a bucket of water to preserve the diamond coated cutting bits. It will be a pain in the butt but it will make cutting easier. You don't want to ruin your bit because a damaged bit will not cut or will take forever to cut.

Cuts through brick and cinder blocks easily!

The product worked great other than the Allen screw that holds in the drill bit. It doesn't hold it in tight and if you try to tighten it, it will break.

This is an awsome core drill, i was skeptical at first, because of some bad reviews i saw. But this thing went thru a foot of rock wall with no issues. Bit is still intact,all teeth are good. Would definitely recommend it.

I bought this bit to bore a 4 -1/2" hole in my 5in thick, steel reinforced concrete in my upper patio to drain the Dry Below system. I used a 12 A hammer drill in drill mode. I used a little water and the bit walked through the concrete and steel in about 10min using no pressure just the drill motors weight. This bit performed perfectly. Thanks for asking.

I am very pleased with this purchase and it does a wonderful job, great value and paid for itself in less than an hour!!!

Now, this is a Diamond head drill! Awesome!!