Drilling holes in concrete

I have to anchor a stud wall in a concrete floor. Any tips in using carbide drill bits? Seems like when I use them to drill in concrete block I can usually only get one or two holes before the bit is shot. Should I use cutting oil or water to cool the bit? Any other tips or tricks you folks are aware of?

Appreciate the input, and ya'll have a very Merry Christmas.

Thanks again

Dog's Friend

I bought a hammer drill from Grizzley Industries a couple years ago for $100 (with a few bits) and I think it is one of the best tool values I ever got. For drilling holes in concrete, an hammer drill made for the task is essential. My drill it looks like a green mini-Hilti. I doubt it would stand up to constant / commercial use, but for using it around the house a couple times a year, it can't be beat.

I've seen what looks like the exact same tool in Northern Tools and Equipment, and in Habor Frieght catalogs for less - like $80 or $90. I don't know if the ones sold in those catalogs are the same quality as mine, but I would not be suprised if they were made at the same factory.

I recommend you go with one of these; If you got the Grizzley version, I'm sure you won't be sorry.

On wood plate, drill 1/4 hole through wood into concrete, drive two 16's nails in same hole, move on to next job, keep it simple!!

I bought this drill to drill the holes in the slab with but knew it would not see that use again soon, so I wanted a standard chugk for normal drilling in wood and metal. Has been useful around the shop for that, good investment.

Billy has covered fasteners well. HomeDepot has redhead fasteners and others, should be easy to do with them.

Charles

You should be using a hammer drill with a masonry bit, there are many out there that have the hammer option on the drill but also are just like a regular drill. Masonry and concrete vary in compressive strength, hardness and density, also if you hit rebar, it slows things down, and or can be impossible to complete a hole. I've done extensive masonry fastening in my career, including all kinds of pull tests etc. etc., so I have to keep from getting carried away here LOL

Most drywall guys use a powder actuated fastening system. like a Hilti, Rawl/Powers, etc. which is like a .22 caliber powered shot that shoots a fastener into masonry, concrete and steel, when fastening bottom or top track on large scale basis, just quick and easy after they lay out the walls, but the home owner most likely willnot use this tool and fastener very often.

You can probably rent a small drill with the hammer option and match up the correct size masonry bit ( not a regular bit ), Hilti are more expensive, but they do perform and last long. You could use 3/8" dia. or the next one smaller, like what Hilti calls a Sleeve Anchor, commonly referred to as an expansion bolt. Use the matching size bit in the hammer drill, drill the hole to the correct depth, not too deep, clean the hole, insert the expansion bolt, tighten down and the sleeve which is like a dove tail, will tighten up in the hole, and is very strong so you will not need a lot of these. Remember to include the thickness of what you are fastening and the depth of your embeddment and a 1/4 to 1/2" extra when selecting fastener length. If your bottom track is wood, it's 1 1/2" plus say a 2" emebedment = 3 1/2", so a 3/8" dia. x 4" long sleeve anchor or expansion bolt would be fine. Once you have an expansion bolt secured, the threaded stud will be sticking up and you can drill holes through your bottom track and make the connection. You can pre-tension like I mentioned or layout the stud, drill through both and then tighten, I like the first method, I know the fastener is anchored securely 1st., large scale jobs this would be too labor intense.

All concrete and masonry is usually not bad to fasten into, but if you hit rebar or open voids it can be a problem, high strength concrete masonry units C.M.U. or block as most people call it, if fully grouted ( cells filled ) is similar to concrete, but if hollow, can be a problem.

There are a ton of fastener manufacturers out there, all with their gimmick or claim to fame, but they usually have plenty of catalogs available, you can learn a lot from reading a Hilti catalog. Home depot carries a small line of Hilti now, but large quantities are best obtained from a dealer.

LOL, if I have confused you a bit, you can resort to masonry nails ..... but make sure you use a large hammer and EYE PROTECTION ! LOL Kidding, see the Hilti rep. at the local H.D. if they have one on site, you'll learn some interesting things on the subject.

To do this I burned out two 3/8" VSR Hammer drills. I upgraded to Milwaukee 1/2" VSR Hammer Drill and never looked back.

They make masonary bits and you should get a couple of those. They have an extended lip on on the cutting edge that cuts the hole. I drilled 48 (6 per upright) 1.25" holes to a depth of 6".

Do not add water as it tends to make a psuedo mortar mixture in the hole. I drilled a small pilot hold and then centered the large bit over that. From there I just started slowly and with the hammer feature drilled out the holes.

I would drill 1/4 to 1/2 the distance and then use my shop vac to periodically vacuum out the dust that did not come when retracting the bit. I would continue until I reached the desired depth.

NOTE: Don't go to fast otherwise you will take the temper out of the cutting edge and the bit will quit cutting.

HTH

The ones I mentioned above are a bit overkill, but I can mention one example of bad fastener selection in conjunction with hollow C.M.U. walls.

Was in Wellington Fla. last year to do some vacationing and do some repair work at a high end stable in that section where the horse people gather for winter, ( step-mom is a trainer for the owner there and migrates there every year) .
I've never seen barns like these, I'm used to what most people are accustomed to, but when I was there, many of the hardware fasteners were pulling out on the horse stalls locks, and the exterior storm shutters. Upon examination, I found that the exterior was C.M.U. (block) coated with stucco, dryvit or some similar finish, and the interior the same. This application requires some coordination during construction, as the fastening areas should have no voids and the fastener selected should not have been a tapcon, they will not perform or achieve tension/shear values like an expansion bolt will in a solid substrate, the sad thing was that when it was built, money was not an issue, good thing was that I found an equivalent Hilti fastener, Quick Bolt to replace the failing tapcons, and lucked out that the diameter of the hole was very close to what I needed to make it work, however the C.M.U. was hollow, so you have to be careful as you only have one chance to repair these correctly or you do have a mess on your hands. All the owner had to do was have a construction person, make the correct fastener selection for the application, and coordinate filling the cells of the C.M.U. wall near the connections, then they would not have this problem today, eventually I'll have to replace them all, as they will not hold up under the usage they get. I find a little overkill can be well worth it, 2 years after a building is complete is not the time to have failures like this, could have been easily avoided. I hate seeing things like this happen, but at least the repair was easy in this case, if the holes got any bigger, all the hardware would have to be either modified or replaced, costing a lot more than doing it right the first time. In a high wind the shutter anchors may pull right out, unbeknownst the owner, contractor definitely went cheap on them, and money was no object for the job.

Don't mind me babbling along here like a sidewalk superintendent know it all LOL, those tapcons are fine for an interior wall bottom track, but for high performance applications best to check the details carefully ahead of time or end up with a scenario like the above. If this were an exterior wall subject to wind loads, a tapcon would be the wrong choice, in my ridiculously overkill but humble opinion LOL !! Another favorite subject of mine, good excuse for babbling I suppose ! LOL

Merry Christmas & Happy New Year to all, great bunch of people on this forum !