Drilling concrete wisdom

[Txtourist]

Moving our cabinet and millwork shop around and having to drill a dozen or so holes in a slab to anchor machines and I’m having the hardest time.
Using a Bosch hammer drill we’ve had forever and drilling 3/8” holes with a fresh bit.

[Hoggslayer]

Is the Hammer function working properly? Are you hitting rebar?

[droebuck]

As in a roto hammer or an actual hammer drill?

[trophyhunter01]

Get a big electric that uses spline bits, the smaller more homeowners types don’t have enough punch. Go to the rental store, HD has some usually. Old concrete is hard stuff.

[droebuck]

Get a big electric that uses spline bits, the smaller more homeowners types don’t have enough punch. Go to the rental store, HD has some usually. Old concrete is hard stuff.

This^^^

[RMW]

Are you using a bit made for concrete? Should be fairly easy to drill holes unless you hit the rebar.

[KDinTX]

Is the drill an sds bit styled drill or just a drill with the hammer feature that uses standard concrete bits. If it’s an sds style drill it should blow through easily if the hammer feature is working, I’ve drill thousands of holes in concrete, old, new, etc with sds drills up to 1 inch bits.

The regular drills with hammer option don’t have enough gust to them to get into concrete very well, very similar to the 18 volt drill/driver/hammer drill.


You shouldnt need a sds max or spline drill for 3/8 holes. Way overkill on that drill.

[RifleBowPistol]

I have drilled numerous holes in concrete, to install Redhead threaded inserts. I found masonry bits are not worth a crap at drilling through rebar. Then at the same time, a high speed drill bit will get very dull, very quickly if you drill into concrete, or even a hole that has concrete chunks or dust in the bottom.

What I had to do was drill as deep as I could with the masonry bit, till I hit rebar. Then use air to blow out all of the concrete dust and chunk. Then drill through the rebar with a common high speed drill bit. Then back to a masonry bit. Then also when using the high speed steel bit, use a common drill and turn the speed down some. You may have to center punch the rebar to get the high speed bit to not walk off of the rebar. If the high speed bit walks off of the rebar and drills into concrete, it will kill the bit quickly.

Then at times, I would hit rocks, that I would have a lot of trouble getting through, really could not even get the masonry bit to start drilling into. For those I would get a long punch and hammer, then break the rock. Then the masonry bit would go through the rock.

The first time I borrowed a hammer drill, I figured it was going to drill through the concrete quickly. The first few holes I drilled, it was quick. Then I hit rebar for the first time, that brought things to a stop. Then it seemed about every hole after that one, I hit rebar. A hammer drill is great, until you hit steel.

[Kingfisher789]

Is the Hammer function working properly? Are you hitting rebar?

Right. Been there. Use some water to cool the bit and go slow OP

[Low Fence]

You need this and the size bit for it…. Piece of cake

[Hagen]

Hilti T 40 works well for me. If you hit rebar just adjust drill holes a bit.

[Draco]

Don't push down hard on the drill. Let it drill with the weight of the drill alone.

[CabezaBlanca]

Is the drill an sds bit styled drill or just a drill with the hammer feature that uses standard concrete bits. If it’s an sds style drill it should blow through easily if the hammer feature is working, I’ve drill thousands of holes in concrete, old, new, etc with sds drills up to 1 inch bits.

The regular drills with hammer option don’t have enough gust to them to get into concrete very well, very similar to the 18 volt drill/driver/hammer drill.


You shouldnt need a sds max or spline drill for 3/8 holes. Way overkill on that drill.

This right here.