Bosch HC6521 2-1/2-Inch x 18-Inch x 24-Inch Wild Bore Thru-Hole Multi-Cutter Head SDS Max Rotary Hammer Bit, Silver

It’s heavy and dulls fast. It does work

Bores holes in basalt rock - off label use but what I needed to do. Holes need frequent cleaning, but it did the job, 20+ 18 inch deep holes and still working fine.

We use to get a year or more out of these. Now they start breaking at a couple months. Quality control seems to have diminished over the years

I was able to drill 8 holes in solid basalt with this bit. We went a full 24" with the Hilti chuck going into the hole allowing a deeper footing for the uni-strut holding the solar panels. Word of caution: we got stuck two times, the first time because we went too long between vacuuming the debris out of the hole and it built up on the top of the bit and prevented removal of the bit, We removed the hammer and put the vacuum hose down in the shaft of the bit and we were able to clear the blockage. The second time a rock fell into the hole at about 14" of depth and lodged on the top of the bits flanges and the side of the hole, we had to use a smaller roto-hammer and bit and break the problem rock up and retrieve the large bit.

Great for any item that can be moved out the way, through the tilling process. Plugs easily, when in dirt & rocks. The “cup” plugs easily & needs to be cleaned a lot. This adds to the work process.

I used this Bosch Bit to drill into solid concrete for a fence installation utilizing my Bosch Hammer Drill. This bit pulverized the concrete while rotating the material out of the hole. I would highly recommend this bit.

Augering through limestone and this thing gets it done. Still going strong after several holes. Stop often use a shop vac to suck the material out of the hole and use water in the hole to aid in cutting and to keep the bit cooler.

I’m drilling thru cinder block walls. This bit cuts like a “hot knife going thru butter”. ‹(•¿•)›

Good price for everyday use

As described and works great.

Great product

As expected from amazon and Boschexcellent serviceLike the price and the delivery from amazonWill buy againR