Drills and Bits for Anchoring to Concrete Slab

[MrMunich]

(My first post here   I believe this is the appropriate board to post this; if not, move as necessary!)

Background
I have very little experience with any construction/renovation/etc, but I'm taking the time now to research all of this and come up to speed.  I'm excited about finally being able to do simple things myself.

I'm going to be building a pre-fabricated backyard office, and I'm using this project as a justification to get a variety of tools which will be used for more project going forward (a deck, some fences, some minor home renovation, etc.)  I get an enormous amount of enjoyment out of both using the right tool for the job, as well as using a high-quality tool.  Thus Festool has sucked me right in

Drilling the Holes
I'm most anxious about attaching the structure to the concrete slab, and wanted to make sure I had both the right drill(s) and bit(s) to do things properly.  I have a ~5" deep concrete slab that I'm going to be drilling 1/2" wide 3" deep holes into to install Simpson strong tie bolts (info).  I take it the BHC 18 rotary hammer is the drill for the job here?

Bit-wise - I see some SDS-plus rotary hammer bits that should work (example from Amazon).  If I'll be drilling ~30 holes, should I worry about the bit lasting till the end?

Since I'm not using epoxy, I don't believe I need to be super careful about getting 100% of dust out of the holes, or brushing anything - but would the "drilling dust nozzle" (500483) take out most of the dust?  Note that there will be 3" of wood on top of the hole, so the actual total depth of the hole will be 6" (3" wood + 3" concrete).  Would the dust nozzle meaningfully keep the hole clean, or should I be blowing compressed air down there, regardless?

If I...accidentally drill all the way through the slab somehow, anything I can do to patch things up?  I will use the depth stop, but just want to be prepared in case things go south.  If I somehow hit the rebar reinforcement and have to move the hole slightly, should I try to fill in the original cavity?

Driving the Bolts
For driving in the 1/2" Simpson strong tie titen bolt (has a 3/4" bolt head) - would the TID 18 be best due to the high torque?  Does the PDC 18/4 shine here instead?

For the bit I see the 495133 3/8" centrotec socket adapter, and would look for a 3/4" socket to attach.  How does that item differ from the 769064 adapter?

A lot of questions ;D  Again, I hope they were Festool-specific enough to be reasonable for this board. Thanks in advance for any comments to help make sure I'm not too far off track!

 

[Ron B]

I just want to mention that I see Beaver Tools (St. Louis) have some Festool concrete bits on clearance price.  Just trying to help you spend your money.

 

[Birdhunter]

I’d buy a true SDS drill. I like my Bosch SDS drill. It has a depth limiter that would stop you going through the slab. The Bosch SDS bits are excellent.

 

[AlexThePalex]

I would also prefer to have a regular corded SDS drill than the BHC18. Knowing my Metabo UHEV 2860-2 Quick you get so much more drill than the BHC could ever deliver. The BHC can't even chisel.

I also concur that the Bosch SDS bits are awesome and you'll certainly get your 30 holes out of them and much more. Just buy a respectable brand and not the cheap ones.

As for filling wrongly placed holes, it is not necessary unless you see them. You can fill them with some thin concrete mortar but there are also special caulks to fill concrete. Better make sure not to drill through your slab by using a depth stop or using the good old fashioned method of marking the depth on your bit with tape.

 

[demographic]

Bosch do very good SDS drill bits and one should easy do 30 holes unless theres steel re-enforcement in the concrete. Hitting that can drastically shorten their life. Give it a go and see, if you can just nip somewhere local and buy another then its no worries but if not and it will stop your project its maybe worth buying another bit just in case.

I have the batteries and charger already but when I needed another SDS drill I avoided the Festool BHC cos the spec showed it to be pretty lacking.
I bought a Dewalt brushless thing that can manage light chiselling and can have a small dust extractor fitted and powered by it. I've not bothered with that extra step yet though.
So far thats been good enough for me to leave the corded Hitachi SDS at home but if I were drilling a few hundred holes I'd be using the corded drill instead.

 

[Birdhunter]

Its pretty easy to set up the nozzle of a dust collector close (very close) to the hole you are drilling. I'd strongly advise wearing a respirator or a face mask plus safety glasses. Inhaled concrete dust can reset once it encounters the moisture in your lungs.

I usually apply duct tape over the concrete where I plan to drill and mark the hole location with a Sharpie. Somehow, the tape minimizes the spalling around the hole.

I use two-part epoxy if I need to fill a hole in concrete. I don't want water coming up through the hole and I don't want a fracture emanating point. Two-part epoxy is a great anchor for fasteners in concrete. Warning... fasteners glued in with two-part epoxy will outlast your lifetime. I do put a "dam" of blue tape around the hole to avoid getting epoxy smeared around.

 

[rst]

I use Festool (small) and Bosch (large) hole vac attachments, both work great.  Most of my work is commercial entrancebinstalls so I install alot of thresholds and otjer holes.

 

[Cheese]

I've had really good luck with the newer Milwaukee 4-cutter line, they're made in Germany. They have holes in the cutter end and a hollow shaft that you attach a dust collector to. That way you've solved both of your problems, no silica dust in the air & in the bottom of the hole and longer bit life because you're constantly evacuating the abrasive silica.
https://www.milwaukeetool.com/Produ...ling/SDS-Plus-Drill-Bits/SDS-Plus-Vacuum-Bits

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[Bob D.]

With all the concerns that have been raised over the decades and finally recognized by OSHA (silica dust exposure risk has been known as long as it has for asbestos) concerning silica dust in the work place the new standards regarding capturing and controlling silica dust should be at the top of your list as far as tooling requirements.

Engineering controls like dust collectors are preferred to dust masks/respirators which are considered the last line of defense against airborne hazards. In the case of silica dust it is best to use both. If your only defense is a mask then when dust gets past it there is no other chance to protect your lungs. If you capture most of the dust at the source (the tool) then your mask can catch the rest.

I also believe that a true SDs drill is a better choice for installing concrete anchors. I would rent a proper SDS hammer drill setup as this is a task you most likely are not going to do on a regular basis in a DIY setting. For a job that a HO/DIY might perform once or twice a year renting the proper equipment is the way to go in my opinion. Plus a SDS dill will be much faster drilling. At 1/2" dia. and 3" depth these are relatively small holes. I've never used the Festool PDC18 but I don't see it out-performing a Hilti or Bosch SDS drill. Different tools for different jobs.

The requirements in the silica dust standard are why everyone from Hilti on down have brought out new tool lines along with accessories and consumables like bits in the past decade.

First question is if there is any conduit or other commodities in the slab they should be de-energized. With a cordless drill not as dangerous but with corded tools contacting an energized line is not fun (or cheap).

I would remove all the dust from the hole. I would also fill any abandoned/unused holes with grout or epoxy as open holes will let  moisture enter the concrete and create a path for corrosion to attack the rebar.

If you have a 5 inch slab your rebar should be near the bottom which is where rebar does its work most effectively as it works under tension. Most jobs where I have installed concrete anchors the rebar has 2 inches of cover which in your case would put it 3 inches down so near the bottom of you hole. But my experience is on large construction projects so may not be applicable to your case. In a slab such as yours hitting rebar and having to drill through it is more of a nuscience than an engineering/structural integrity concern. It will reduce the life of your bit, not much you can do about it unless you can move the hole location. If you are worried about hitting rebar or conduit drill a pilot hole with a smaller bit say 1/4". It's not 100% foolproof but can increase your confidence that you have a rebar free location.

Your holes also should be slightly deeper than the required minimum embedment. Even after you vacuum out all the dust when you drive the anchor (since these are threaded not expansion type anchors) in the threads will shear off some dust which will fall to the bottom and could stop you from achieving the minimum embedment depth. A 1/4 to 3/8 of an inch should be all you need. If your hole is not deep enough your anchor will bottom out when tightened and never achieve the clamping force required to secure the load to the slab. Another concern I would have with threaded anchors is if you overtighten (which is possible if using an impact tool to set them) you could possibly strip out the hole. On smaller diameter anchors you could also shear off the bolt. Do the installation instructions give an acceptable torque range for setting these anchors?

 

[acer66]

I've had really good luck with the newer Milwaukee 4-cutter line, they're made in Germany. They have holes in the cutter end and a hollow shaft that you attach a dust collector to. That way you've solved both of your problems, no silica dust in the air & in the bottom of the hole and longer bit life because you're constantly evacuating the abrasive silica.
https://www.milwaukeetool.com/Produ...ling/SDS-Plus-Drill-Bits/SDS-Plus-Vacuum-Bits

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Thank you for sharing this.

 

[RussellS]

Replying only to the type of tool you need.  I use the Makita HR2455 1" D-handle SDS-Plus 3-mode Rotary Hammer drill when drilling in concrete.  Its perfect for drilling Tapcon screw holes for attaching electrical boxes and conduit to concrete.  It can drill bigger holes too.  Little under $200 retail price.  I would suggest a similar electric powered drill of similar size for drilling into concrete.  Normal size holes.  SDS ROTARY Hammer drill is key.  NOT hammer drill only.
https://bigskytool.com/makita-hr2455-1-rotary-hammer-with-d-handle-3-mode-reconditioned.html

 

[CeeJay]

Agree on a rotary SDS hammer drill. A decent used corded unit should be pretty cheap. I still use a 25 year old Kress SDS+ drill which works great.

I have found Hilti SDS+ bits are excellent. I am still using some of the original bits I bought with the drill 25 years ago.

I occasionally eye up a Makita 18V SDS+ skin but for the rare occasions when I’d need it the Kress is doing fine. If it ever dies I will probably go cordless.

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[elfick]

I admittedly have no experience in this, but I'm confused by the couple of posts that have mentioned a "true SDS drill"... The BHC18 that the OP posted is a SDS-Plus Rotary Hammer Drill. How is that not a "true SDS drill"? I'm not advocating for the BHC18 here or against anything else. I'm just confused by the terminology being used.

 

[MrMunich]

First of all - thank you very much to everyone who has responded thus far!  All helpful replies, covering things from a variety of angles (many of which I hadn't done enough leg work researching myself, yet!)  Specifically, [member=60461]Bob D.[/member] 's comments about the origins of silica dust awareness and OSHA actions helped me put things into context (as well as helps justify purchasing a CT MIDI to make sure I'm super safe ), and his specific fastener considerations were wonderful.  Also [member=15289]Birdhunter[/member]'s multiple replies, and specific information on using two-part epoxy as a safety net in case things go awry.

I admittedly have no experience in this, but I'm confused by the couple of posts that have mentioned a "true SDS drill"... The BHC18 that the OP posted is a SDS-Plus Rotary Hammer Drill. How is that not a "true SDS drill"? I'm not advocating for the BHC18 here or against anything else. I'm just confused by the terminology being used.

I think people may have seen my mention of the PDC in the "driving the bolt" section, and wanted to make sure that I wasn't going to try to use that for the reasonably heavy lifting of actually drilling all the holes!

Indeed I pulled the trigger and got a BHC 18  ;D  It does feel like a bit of an exorbitant purchase given the variety of other perfectly capable options for a decent amount less, however sticking with the same batteries-chargers / the ergonomics / the systainer storage / etc. was enough to convince me.

I'm still unsure of the best tool for driving the bolts.  Someone mentioned that an impact tool could over-tighten the bolts, so perhaps the fine-grained torque control on the PDC 18/4 would shine here?  Again - I have very little experience with any of this, so I'm trying to build up my knowledge and intuition

 

[AlexThePalex]

I admittedly have no experience in this, but I'm confused by the couple of posts that have mentioned a "true SDS drill"... The BHC18 that the OP posted is a SDS-Plus Rotary Hammer Drill. How is that not a "true SDS drill"? I'm not advocating for the BHC18 here or against anything else. I'm just confused by the terminology being used.

The BHC 18 is a true SDS drill.

Dunno why people would say otherwise. Maybe they meant that the BHC is rotary only and lacks a chisel mode? That's not what makes something an SDS drill, the SDS connection is what does it. Still, if you see what tools you can get in the SDS market, the BHC is about the bearest minimum that exists, only useful for drilling the smallest of holes.

But good luck to the OP with your new purchase, hope you enjoy it.

 

[Spandex]

Tbh, for 30 12mm holes in concrete, pretty much any SDS will do, and that includes the BHC. Even a decent hammer drill like the PDC will do it, although obviously much slower (I know because I’ve used my PDC for exactly that, before I had a cordless SDS, when I needed to drill some holes in a concrete pad with no access to power).

I wouldn’t overthink this.

 

[Bob D.]

Looks like I was confusing the BHC18 with the PDC18. Sorry about that.

I found this recent FT Live video which compares the two.

 

[oldie]

No need to repeat all the useful info' already given.

I use Makita Nemesis bits - will deal with anything that might be in the concrete; including the vague possibility of hitting rebar.  Lovely accurately drilled holes. 

Definitely get as much dust out as possible. 

With the BHC, would consider drilling a pilot hole first - say, 5mm / 6mm; would ensure the BHC has a slightly easier life. 
I consider 12mm is on it's limits of 'comfort'; particularly if drilling x30 holes in fairly quick succession.

Richard (UK)

 

[Birdhunter]

I suggest you go handle a “true” SDS drill like the Bosch and compare it to the Festool unit I love my Festool products, but when making a bunch of holes in concrete, I unpack the big hog.

 

[CeeJay]

For torquing the bolts a decent socket wrench is all you need.

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