3-1/2" Wet Drill Core Bits for Concrete and Hard Masonry, 10mm Segment Height, 14" Drilling Depth, 1-1/4"-7 Arbor, Wet Only

I needed to drill a hole through a 8" thick 45 year old concrete wall to run the lines for my new heat pump. I picked up this bit, a 1-1/4"-7 Male to 5/8"-11 Female adapter, and a Makita 9566CV variable speed angle grinder. I created a plywood jib to hold the bit in place had an assistant run the garden hose while I set it against the wall and turned it loose.Eight inches of concrete stretched my little angle grinders abilities. As the grinder motor heated up we took a couple "lets go work on something else" breaks. As the bit gets deeper into the wall, it gets harder to keep the bit perfectly aligned and so extra "drag" starts making the amount of work to be done much higher. When I figured that out, I busted out the core slug which made a large difference, and was able to finish up the drill without any further overheating of the grinder.

I used this core drill to make the holes necessary to install a radon mitigation system in my house. I used this 5” core drill to make a hole large enough to install 4” schedule 40 PVC pipe, which has a 4 1/2” OD. I drilled through a 4” basement slab and a 6” concrete side wall and the drill still looks to be in great shape. I used a heavy duty Milwaukee hammer drill to drive this, but I did not use the hammer feature. My wife sprayed water into the drilling area using a pump up lawn sprayer during the drilling process. It seemed like a pretty slow speed gave the best results. This took a while to drill through and I had to cool off the drill motor a number of times during the job. This was money well spent.

So far drilled 20+ holes and have no issues at all. I bought new and used bits and still using the first bit

The product worked great and was the best value for the dollar. Used to core 6 inch wide holes in 6 inch deep patio. Used a 7 amp drill and but could only run 5 minutes at a time due to over heating. are used this adapter to fit it on my corded drill ( HEX500-2 Core Bit Adapter with 1-1/4"-7 Thread to 1/2" Shank https://www.amazon.com/dp/B01N7UABOF/ref=cm_sw_r_cp_api_i_SKkbFbSH4BGNX ). Had water running on it the whole time. Cut rebar no problem.

Worked great with my little Bosch Bulldog hammerdrill with the "hammer" function turned-off (with an SDSPlus adapter I also bought on Amazon). I didn't have a pilot bit, but used an old trick for drilling holes in tile - tipped the drill bit 15-20 degrees off vertical and slow bit speed. I made a V with my feet with the bit resting at the vertex of the V, and used just the edge of the bit to start the hole. My daughter kept the bit lubricated with a 1 qt. spray bottle of water used to spray the hole/bit interface, and the bit made a perfect hole through the slab in our basement. The bit was great, but the Bosch started smelling like it was overheating before I finished - make sure your drill is heavy-duty, or let it cool down before continuing if it starts smelling or feeling hot.

Worked great

Works great!!

Cooring

The matrix is not as it is pictured. The cost to ship it. I ordered a 2-1/2" and automatically got billed for a 3". the price is good for what it is but the shipping undoes that. Hopefully it doesn't fall apart. Not happy with the shipping cost overall.

Works great. Shipping was way too much.