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Although the terms "square drive" and "Robertson" are often treated as the same in catalogs, the difference (as I understand it) is that Robertson tools and screws have a slight taper to the square recess and the square drive ones do not. Most online sources claim that the tapered design is superior. Some online sources complain bitterly that this slight difference can lead to damaged tools and stripped screws when the two types are mixed up or misidentified by sellers.

(In background, let me add that I am located in the US and am interested in trying them out. Robertson screws are very popular and available in Canada, where they originated, but in the US I can only get them via mail order.)

I assume that if I buy Robertson(R) branded screws and Robertson(R) branded screwdrivers or bits, then I can be guaranteed compatibility. My question is, "Is there any other way I can tell that I will have compatible Robertson tools and screws other than by physically examining them?"

I hope to get answers from people with actual experience buying and using Robertson wood screws and tools.

I have seen photos of some drive bits stamped, for example "SQ2" and others stamped "R2," but I am unclear whether or not the "R" designation is really a reliable indicator of a Robertson taper.

I am also unclear as to whether I am overthinking this, and that maybe the alleged incompatibility between square drive and Robertson is overexagerated in the blog posts I have read.

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    The Wikipedia entry doesn't distinguish between the two. Over many years in the construction industry it's never been an apparent issue for me. #2 square are dead reliable. #1 are more prone to stripping if screws aren't piloted and proper technique used.
    – isherwood
    Oct 4, 2018 at 15:37
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    Bloggers say a lot of things. 20 years in construction (US, Canada), and the key differentiator for me isn't tapered versus not; it's simply quality of manufacture. Some are great; others aren't. (This is also true in the land of phillips, pozidrive, torx, etc.) If you must go square (and frankly, I'm at a loss to understand why this is particularly attractive, given the range of alternatives), just find a brand you like. Oct 6, 2018 at 14:26
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    For me I really do not like them because in 1 panel you might have both square and tapered. Then you end up stripping bits yes I have even used Robertson's for wood screws but today I buy exclusively tork style screws because the bits last many times longer, still have lots of equipment that comes with the square + slotted and those although are quick with an electric driver I have had more problems with them than any other type. But this is just an opinion.
    – Ed Beal
    Nov 9, 2018 at 22:51
  • Actually, I have had #2 square-drive screws strip their heads too -- but that was when power- driving longer screws into pressure-treated lumber without predrilling, so Entirely My Fault. If you predict (which you really should for most screws), I've seen contractors drive these into ironwood at a fairly high rate and never have a problem.
    – keshlam
    Dec 27, 2022 at 16:32
  • If you're going to get picky, you might also investigate parallel-ground screwdrivers, which reduce the risk of cam-out and stripping for slotted screws.
    – keshlam
    Dec 27, 2022 at 16:57

4 Answers 4

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I have used them interchangeably without a second thought for many years, on Canadian and non-Canadian fasteners and Canadian and non-Canadian screwdrivers. No issues, everything works great.

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  • I have used both for many many years. The biggest issue is as with other types, is material of bits and screws and what they will be used for. Also a big big factor is the experience of the user. Harder material needs more pressure on the screw.
    – user68386
    Apr 9, 2019 at 20:01
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The difference is so small, even 30 year construction veterans don't know there's a difference until it's pointed out.

It really only comes into play on a screw that was torqued down so tight that it's almost impossible to remove without a perfectly fitting screwdriver. 99% of screws won't have any issue, but on those few screws that were torqued down, your only hope is a true robertson screwdriver.

I just had two screws fail to come out on a large current transformer metal box. There was no flat-head alternative so my boss had to drill them off.

Also, a true robertson screwdriver will hold a robertson screw on the tip better than a square will.

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I first came across square head trim screws when I worked over the road building mall stores in the 90s. I was told by my boss they were called "Robertson" screws. I have noticed the difference in straight square bits and tapered ones, and it has been my experience here in the US that the tapered (Robertson) bits tend to eat out the heads of screws due to some wobble. Everything it seems today is a Torx head, which is frustrating to me as I prefer square heads. Unless you specifically have Robertson screws, I don't see the need for tapered square bits. Or you could do as I do, and buy both in bulk to hedge your bets.

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My experience is that the Robertson head is far superior to Square or, worst case, Philips. Especially in applications where you need a cheap and fast to use screw (wood decks for example). If I need a true structural screw I go to the expensive Torx. Try getting a Square bit out of the screw socket when you remove them. It really slows you down.

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