Countersinking screws in Hardibacker?

Old 09-24-11, 08:27 PM
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Countersinking screws in Hardibacker?

Does anybody know of a "dimpler" like drill attachment which allows the user to quickly and correctly countersink a screw into Hardibacker?
The dimplers I see advertised are phillips screw drives and mainly for drywall or wood. The recommended screws for Hardibacker have the square (Robertson?) drive heads, which are stronger and easier to drive without stripping than the Phillips drive.
I usually overdrive or underdrive my screws on the first attempt...When I underdrive one and then try to redrive it in further, I end up overdriving it...So to avoid overdriving, I usually end up manually driving the screw in by hand with a ratchet drive...Too time cunsuming and tough on the hands.
Can anybody offer some suggestions?
Thanks all!
Old 09-25-11, 07:39 AM
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I recently did a bathroom and had the same problem driving Hardi screws into 1/4" Hardibacker board. The screws would not countersink completely. I ended up predrilling countersinks with a 3/8" bit. A real PITA. I've used Hardiboard quite a bit and never had that problem - at least not to this extent where 90% of the screws did not sink properly.

I also put up 5 sheets of 1/2" in the same bath and the screws sunk correctly on their own. I have no idea what the problem was.
Old 09-25-11, 11:41 AM
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Be sure to use the screws for hardibacker, and not those for durock. There is a difference. When driving the screws, don't stop the drill. Let the screw stop it, or wait until the screw is seated b4 you let up. Too small a drill will not be powerful to do the job, so let us know what size drill you are using. Don't worry too much about this, as you will be coating it with thinset, anyway.
Old 09-25-11, 12:10 PM
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I don't really think overdriving is much of an issue is it? As long as it doesn't tear away the inner mesh and all. Like was'll be filling the holes afterwards.
Old 09-25-11, 02:31 PM
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I use an impact. I've never noticed any problems setting the hardibacker screws w/robertson bit.
Old 09-25-11, 03:15 PM
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XSleeper's suggestion of an impact is what I was going to mention. I have been helping my son put up a garage and he is using an impact for torque and phillips. Even though his drill is slower, I noticed the torque weren't breaking when removed. My variable speed was breaking 25% of the screws I tried to remove. Point being, the impact seemed to be able to drive or remove with more consistency. I just need to find one that is faster than what he was using .

Old 09-25-11, 03:52 PM
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I don't like to leave screw heads above the hardiboard. It seems to me that leaving a "clicker" under tile is asking for a problem. On the other hand I don't know that for a fact.

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