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.
Best Answer
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.