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-   -   I can't get tapcon screws to tap into the concrete slab!? (http://www.diychatroom.com/f19/i-cant-get-tapcon-screws-tap-into-concrete-slab-8576/)

Monty 05-20-2007 11:28 PM

I can't get tapcon screws to tap into the concrete slab!?
 
I can't get tapcon screws to tap into the concrete slab!?

My husband and I are installing a 5/8" plywood subfloor plus 1" foam over our concrete slab. We are using 3/16 tapcon screws that are 2 3/4" long. We have rented a hammer drill, and are using a 5/32 bit to drill into the concrete. We are drilling down 1/4" longer than the screw, but the screws don't seem to be tapping into the concrete. Our screws will go in so far, but then the head of the screw gets stripped, despite brand new bits. Maybe our regular drill does not have enough power to get the screws to go down?? Do we need a drill with more torque to get the screws to go in?? Does anyone know why we might be having trouble? What can I do to fix this? It states on the tapcon box that for a 3/16 screw to use a 5/32 drill bit, which is what came with the box...and is what we have tried and is not working. We have tried using a 3/16 hammer drill bit as well, but this proved too big.

zel 05-20-2007 11:59 PM

Maybe try the lowest speed setting on the drill? I know sometimes the higher speeds tend to strip the heads. Also, maybe try a square drive, or even a hex head?

RippySkippy 05-21-2007 06:44 AM

Are you using the hammer drill to drive the screws? If not...I would HIGHLY recommend it or an impact driver. When I drove a couple hundred screws for a project last summer with a standard 18V cordless...those babies would just torque and snap in a heart beat...with the hammer drill...piece of cake. You might try the tapcon driver, it's ok...I have it. If you use the same hammer drill for drilling and driving...it'll be quicker than chucking and re-chucking all the time.

You might want to check out the split anchors for this application, WAY faster to install...and I've had excellent results from them in a "no load" application. (look around on this site, there's a ton of information on different connectors and applications, no affiliation)

Another option are the GRK concrete screws...but you'll find them similar to the tapcons.

Good luck.

NateHanson 05-21-2007 03:36 PM

Are you using the right size philips bit? You might need a #3 for that screw.

Clutchcargo 05-21-2007 03:40 PM

You need the socket bit to drive those in. The screwbits just strip the screwhead out..

handy man88 05-21-2007 04:36 PM

Make sure you use a shop vac and remove all the dust in the hole. Try predrilling even deeper. Also, if they were using the wrong size screw bit, the screw would strip before the head breaks off.

Monty 05-21-2007 07:52 PM

thanks everyone
 
we've ended up going with redheads and simply predrilling, then hammering those into the concrete slab. thanks for your advice!

NateHanson 05-21-2007 10:21 PM

Quote:

Originally Posted by handy man88 (Post 45762)
Also, if they were using the wrong size screw bit, the screw would strip before the head breaks off.

Quote:

Originally Posted by Monty (Post 45675)
Our screws will go in so far, but then the head of the screw gets stripped, despite brand new bits.

I think they're saying that the screw heads are getting stripped, not breaking off.

Sounds like they need a hex-socket drive.

(If you have a hex-to-square 1/4" adapter, you can use a regular socket in your hammer drill.)

wingman77 06-15-2009 07:56 AM

Monty I am having the same problem installing floor can you give more detail on how you did it using redheads (what is a redhead)

Thanks

wingman77 06-15-2009 08:19 AM

Having the same problem as Monty I am using 1/4 tapcon x 2 3/4 as well as 1/4 x 3 1/4. Material thickness is 5/8 plywood and 1 inch foam board. I drill the correct hole depth but tapcon does not go all the way down it stops about 3/8 from the plywood .I have tried driving with the hammer drill either breaks the screw or strips the head torque gun just stops driving it is only a 12 volt .I clean the hole properly so I know that is not the problem. Using countersunk hexhead tapcons because must be flush with plywood.:(

Zel1 06-15-2009 09:28 AM

I recently used some 1/4" tapcons and had some minor issues. My advice would be to drill the hole slightly deeper, maybe a 1/4" and use compressed air to clean out the holes. If the drill dust has nowhere to go when the screws get there, its like not having the hole predrilled. Just my .02

RippySkippy 06-15-2009 09:29 AM

Have you thought about using the split drive anchor?

Bronx 06-15-2009 09:52 AM

Tapcons
 
There are many reasons that tapcons fail. You have 1 5/8 of material being fastened to the concrete and the mininum embedment of a 1/4 tapcon is 1" into the concrete. A 1/4 x 2 3/4 tapcon is the correct size.
The hole to be drilled is 3/16. The hole must be cleaned out with a shop vac and driven with a #3 phillip tip driver. When driving the screw use a corded drill that is not a hammer drill.

Willie T 06-15-2009 10:25 AM

Zel1 hit on a very important point..... compressed air. Very often a shop vac will not get all the dust out. And as you are drilling, it pays to pull the bit upward, yanking out as much of that dust as you can about every three or four seconds.

Don't forget your eye protection when blowing out the holes... that crap will come straight back toward your eyes.

HABSFAN2006 06-15-2009 11:08 AM

Quote:

Originally Posted by Bronx (Post 287691)
There are many reasons that tapcons fail. You have 1 5/8 of material being fastened to the concrete and the mininum embedment of a 1/4 tapcon is 1" into the concrete. A 1/4 x 2 3/4 tapcon is the correct size.
The hole to be drilled is 3/16. The hole must be cleaned out with a shop vac and driven with a #3 phillip tip driver. When driving the screw use a corded drill that is not a hammer drill.

Above is the proper procedure that has worked for me everytime.
Ensure the hole is deep enough...Another secret, is to ensure you are perfectly straight, with some downforce on the drill. Also, do not stop for any reason mid way.
Once you get the hang of it, none of them will strip.


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