Holes for Concrete Anchors

[tez929rr]

We have to set some big cluster mailboxes on a concrete pad for a subdivision mailbox kiosk. My question: best tool for drilling holes to mount the anchors? I’m assuming a hammer drill; what is the best bit to use? The anchor holes need to be about 1/2 diameter and 3-4 inches deep.

 

[Terra Nova]

Regular ol' masonary bit in a hammer drill should do the trick. Those aren't terribly big or deep holes so it should go easy enough.

 

[The Tool Tyrant]

Be sure to thoroughly clean the holes to remove any concrete dust as it acts as a lubricant which can prevent the anchor from getting a good bite.

 

[Downwindtracker 2]

That ol' hammer drill works if you patient enough. Those pistol grip drills get pretty wimpy at a 1/4".For half inch, you are better off moving up to a Hilti type drill.

 

[budget76]

Be sure to thoroughly clean the holes to remove any concrete dust as it acts as a lubricant which can prevent the anchor from getting a good bite.

computer dust-off can + its straw makes quick work of cleaning out the hole. Much more convenient than lugging around the shop vac

of course makes a mess, but doesn't matter outside

 

[bassJAM]

Depending on how many holes you have to drill it might be worth renting a big hammer drill from your local Home Depot.

 

[timgunn1962]

SDS drill.

A hammer drill will probably be ok for 4 holes or so, if you are patient.

For anyone who has used an SDS, needing to drill more than about ten holes, the SDS pretty much becomes a no-brainer.

For half-inch holes, even a cordless SDS will eat the job. Otherwise a dirt-cheap homeowner-grade import SDS drill will outperform a premium conventional hammer drill.

As far as the drillbits go, I would take several cheap ones over one premium bit. I tend to buy the premium bits when work are paying and

 

[Bubba Fett]

A good (DeWalt, Milwaukee, or Makita) hammer drill and a high quality masonry bit will work. Clean the dust, but don't breath it.

The best tool is a rotary hammer, but I feel like a hammer drill will be more useful for other projects, and should handle this without much problem.

 

[Downwindtracker 2]

The order of size are hammer drill < 1/4", Hilti up to a inch,, and SDS Max. I can buy packs of name brand Hilti bits cheap, but SDS Max are full price everywhere.

 

[Al Borland]

SDS or SDS-Max. depends on number of holes. Hopefully, there is no rebar in the pads...
In a perfect world, a 4-lobed double helix bit makes better, rounder holes.
Doesn't sound like that's necessary here though.

 

[sparky 1971]

SDS plus rotary hammer should do the trick. I like the Bosch bits, but I don't recall ever using a different brand name bit. I would stay away from a hammer drill, which would be a regular drill with a hammer function. I have found that those are pretty much worthless, especially when the hole size gets over 3/8. I will say that it's easy for me to say that since I have three SDS+ and a spline drive rotary hammer. If you don't think you will be using one again for awhile, look into renting.

 

[tarbellb]

New concrete and less then 10 holes = hammer drill, cheap HD bit and patience

10+ holes or old concrete = SDS time

 

[Downwindtracker 2]

If you use cheap bits, get one for each hole .

Hilti drills were so common that the brand name Hilti came to mean any concrete hole and bolt. The TE-17 was so universal. Go rent a Bosch copy at HD and buy some Hilti bolts. The last box of boltsI bought said DeWalt on them. At a 1/2" you don't need a SDS jack hammer, a smaller drill, Hilti clone, would be cheaper and lighter, and you wouldn't give away any time.

 

[KnurledNut]

We have to set some big cluster mailboxes on a concrete pad for a subdivision mailbox kiosk. My question: best tool for drilling holes to mount the anchors? I’m assuming a hammer drill; what is the best bit to use? The anchor holes need to be about 1/2 diameter and 3-4 inches deep.

What anchors are being used?

 

[tez929rr]

What anchors are being used?

These

 

[The Tool Tyrant]

Wedge anchor...as I stated before, it's paramount to make sure the holes are CLEAN. I have a full set of hole cleaning brushes from 1/4" to 1-1/2". Brushes and a shop vac work great. I prefer to over-drill depth so if you need to remove item, you can then drive the anchor below the surface and patch.

 

[Kscardsfan]

Get you a good SDS drill and a youngster with good work ethic and a strong back to drill those those holes for you.

 

[Kscardsfan]

SDS plus rotary hammer should do the trick. I like the Bosch bits, but I don't recall ever using a different brand name bit. I would stay away from a hammer drill, which would be a regular drill with a hammer function. I have found that those are pretty much worthless, especially when the hole size gets over 3/8. I will say that it's easy for me to say that since I have three SDS+ and a spline drive rotary hammer. If you don't think you will be using one again for awhile, look into renting.

I’ve had good luck with the German made Milwaukee SDS bits as well as the Bosch. The DeWalts we were given on one job did ok at first but seemed to go dull fast.

 

[Rc_Guy]

That ol' hammer drill works if you patient enough. Those pistol grip drills get pretty wimpy at a 1/4".For half inch, you are better off moving up to a Hilti type drill.

Isn't a hilti type drill still a hammer drill? That is all we ever called them at work.

 

[Downwindtracker 2]

One thing : NEVER use an impact on the nut, It will strip the anchor part. I left one machine with three instead of four anchor bolts holding because I got lazy. I noticed it didn't tighten, so I only screwed up one.

They are all hammer drills, from the little pistol grip to the SDS-Max .I have one of each class. The main difference is size, but original Hilti used their own bit attachment. For what he is doing, he needs just a mid sized one. The universal TE-17 is now a TE-25 , goes to show how old I am, but here is the model https://www.hilti.com/medias/sys_ma...-US-Operating-Instruction-PUB-5070809-000.pdf

He doesn't need a Hilti, a Bosch, Makita or what ever will do fine, but he does need one in this size. I have a Bosch pistol grip. I went to use it for a 1/4" anchor bolt, just 1/4" hole in poor quality sidewalk concrete at our house . I was even using a new Hilti bit, they will fit in 1/2" drill chuck. It was a struggle that left me checking the fleamarcket for a used Hilti.

 

[mike93lx]

Get you a good SDS drill and a youngster with good work ethic and a strong back to drill those those holes for you.

1/2" at 4-5" is not that big deal for a good sds hammer.

I'd take it in one or two steps and clean the hole after each.

I did eleven 3/4" holes at 5" this past weekend with my Bosch sds plus. 3/16 to 3/8 to 3/4 worked well. Bosch bits for the smaller two, makita for the 3/4. Cooled the bits by dipping in a water bottle

 

[Rc_Guy]

One thing : NEVER use an impact on the nut, It will strip the anchor part. I left one machine with three instead of four anchor bolts holding because I got lazy. I noticed it didn't tighten, so I only screwed up one.

They are all hammer drills, from the little pistol grip to the SDS-Max .I have one of each class. The main difference is size, but original Hilti used their own bit attachment. For what he is doing, he needs just a mid sized one. The universal TE-17 is now a TE-25 , goes to show how old I am, but here is the model https://www.hilti.com/medias/sys_ma...-US-Operating-Instruction-PUB-5070809-000.pdf

He doesn't need a Hilti, a Bosch, Makita or what ever will do fine, but he does need one in this size. I have a Bosch pistol grip. I went to use it for a 1/4" anchor bolt, just 1/4" hole in poor quality sidewalk concrete at our house . I was even using a new Hilti bit, they will fit in 1/2" drill chuck. It was a struggle that left me checking the fleamarcket for a used Hilti.

I know what he needs, I have put in a few thousand anchors over the past 25 years.

 

[Downwindtracker 2]

If he rents one, he will need a new bit. I like Hilti instead of the SDS Max, I can buy half a dozen Hilti bits for the price of one SDS bit. They are all name brand, but not Hilti.

I have never drilled a hole in concrete in steps. A lot of the time I didn't have a shop-vac or air. But if you drill and pull back a little to clean the hole, you can get away with it. That squeeze bulb is always mising from the kit,anyway. It's the same trick as drilling long holes in timbers.

When I started 50 years ago the drill brand was Red Head, Hilti pushed them right off the map in construction.

 

[timgunn1962]

As Downwindtracker says, SDS plus bits (aka Hilti, though it's not quite that simple....) are available up to "about" an inch. I've used them up to 30mm in drills with enough impact energy. The SDS drills have an electropneumatic mechanism which provides much greater impact energy than a conventional hammer drill, though fewer impacts per revolution.

The impact energy is usually measured in Joules. The impact energy broadly follows a Joule-per-kilogram of machine weight relationship, with the heavier 3 kg-plus SDS-plus drills reaching 3J to 5J and able to handle the 30mm bits. If you need more, the next step up is usually an SDS-Max machine (there is actually an SDS-top, which seems to have been intended for 3J-5J machines, but that does not seem to have been widely adopted by drill manufacturers). At the lower end of the scale, there are lighter SDS-plus drills with impact energy between 1.0 and 1.5J and weighing 2-3 lb. These are great machines for most users. Here in the UK, brick-built houses tend to be the norm and sub-2J SDS drills are very good at drilling brick without knocking the backs out. Using a heavier drill with a harder impact tends to be counter-productive, as it only saves a few seconds per hole and the damage that can be caused knocking the back out of a brick is way too much to make it worthwhile (YMMV: brick varies massively according to the local geology. Around here, we have a lot of very hard brick, much of it used to build houses. The Empire-State building was constructed on foundations built from imported "Accrington Nori" bricks made here in Lancashire).

The impact energy needs to be damped by the mass of the machine to limit Hand-Arm Vibration.

TBH, any SDS-plus will happily deal with 1/2" holes vertically downward into concrete, so you can think about other things you might want to do with the drill. SDS-plus drill often have a rotary-only setting. This is usually quite slow and the drills can usually develop pretty good torque.

 

[tarbellb]

One thing : NEVER use an impact on the nut, It will strip the anchor part. I left one machine with three instead of four anchor bolts holding because I got lazy. I noticed it didn't tighten, so I only screwed up one.

They are all hammer drills, from the little pistol grip to the SDS-Max .I have one of each class. The main difference is size, but original Hilti used their own bit attachment. For what he is doing, he needs just a mid sized one. The universal TE-17 is now a TE-25 , goes to show how old I am, but here is the model https://www.hilti.com/medias/sys_ma...-US-Operating-Instruction-PUB-5070809-000.pdf

He doesn't need a Hilti, a Bosch, Makita or what ever will do fine, but he does need one in this size. I have a Bosch pistol grip. I went to use it for a 1/4" anchor bolt, just 1/4" hole in poor quality sidewalk concrete at our house . I was even using a new Hilti bit, they will fit in 1/2" drill chuck. It was a struggle that left me checking the fleamarcket for a used Hilti.

NOT TRUE- a SDS has a different mechanism then a chucked "hammer" drill

To your point at the end, a hammer drill can not perform the same task as a SDS type drill

 

[IndyGarage]

NOT TRUE- a SDS has a different mechanism then a chucked "hammer" drill

To your point at the end, a hammer drill can not perform the same task as a SDS type drill

This:
A hammer drill is a toy compared to an SDS.

Several years ago I was drilling a bunch of 3/8 anchor holes to anchor the base of my pallet racking. I spent hours struggling to drill a few holes with my Milwaukee Holeshooter with the hammer function.

I went and got a Hilti SDS. Literally 5 seconds per hole. It was 100 times faster and made it easy. If you have 1 or 2 holes to drill, the hammer function on a conventional drill might work. More than that, get an SDS type Hammer drill and get the job done.

 

[haveissues]

Cooled the bits by dipping in a water bottle

I would avoid doing this. Cooling carbide from the beginning and keeping it cool is fine but shock cooling carbide is a bad idea. Carbide can withstand a lot of heat, way more than any tool steels but rapid cooling can fracture it.

 

[mike93lx]

I would avoid doing this. Cooling carbide from the beginning and keeping it cool is fine but shock cooling carbide is a bad idea. Carbide can withstand a lot of heat, way more than any tool steels but rapid cooling can fracture it.

None of the bits were getting so hot that warm water was a shock. Plus I need to be able to handle the bits, so it is what it is.

Not like I was getting a bunch of steam when dipping them.

 

[Downwindtracker 2]

I was mistaken, what is called SDS is really the what we called Hilti. Someone as much a tool nut as me, had to look it up, Hilti was that universal.

My point was I had chucked a brand new expensive drill bit, and still had difficulties.

I bought a Bosch SDS Max, because I needed an jack hammer to remover fused foam rubber underlay before installing laminate.It worked OK. I bought a bit for it and cried., I di drill three 1/ holsAt work we had both the mid and large size Hiltis. I found a obsolete dainty TE-12 Hilti at the fleamarket. 4.5amps. I went through a box of 1/4" Hilti bolts, which were labeled Dewalt, in short order on a volunteer project . What had been a real struggle to do only 1 hole with a pistol grip hammer drill ,a 5mp drill motor, was very quick and easy with the Hilti.

 

[toplessHO]

If he rents one, he will need a new bit. I like Hilti instead of the SDS Max, I can buy half a dozen Hilti bits for the price of one SDS bit. They are all name brand, but not Hilti.

I have never drilled a hole in concrete in steps. A lot of the time I didn't have a shop-vac or air. But if you drill and pull back a little to clean the hole, you can get away with it. That squeeze bulb is always mising from the kit,anyway. It's the same trick as drilling long holes in timbers.

When I started 50 years ago the drill brand was Red Head, Hilti pushed them right off the map in construction.

and before Phillips redhead there were star bits and a hammer
Its amazing we got anything done back then
I remember when TapCons came out,we all said that wont work and that wont last
If the holes arent drilled correctly,use epoxy set studs

 

[Rabid Badger]

A Bosch Bulldog-style rotary hammer is a nice tool to have around for stuff like this. You can pick them up used for $50-75 pretty easily.

 

[tez929rr]

FWIW a Milwaukee 18V hammer drill went through the concrete like butter.

 

[nadogail]

When my boss told me that we were getting pallet racking and it would be my job to get them assembled and anchored, he asked me what would I need.
I said "If there is enough money in your budget for a Hilti drill it won't be hard at all; we have everything else". He found the money for the Hilti and it walked through the concrete like Sherman through Georgia .
I deep drilled the holes, blew the dust out with LP air, and set Hilti Qwick Bolts. Because the holes were deep drilled, if and when the racks were no longer wanted; the bolts could be driven down into the holes.