umm neither of those examples is actually correct on metalworking machinery they are dovetail slides they don't join they make a sliding fit which is resistant to lifting you can achieve the same effect with box ways by putting a sliding surface along the opposite side from the main bearing surface but a dovetail is cheaper to make in turbines they are not called dovetails and they are not the same shape they are called christmas trees in the shop my aging brain has forgotten the correct technical term but it ain't dovetail they are shaped like an upside down christmas tree with no sharp corners the principal is similar but not the same as a dovetail also in general they are once again not a tight fit they have to have a fair amnount of clearance to account for large temperature variations in operation they actually rattle around some so once again as this article is mostly about permanent or semi permanent joints the use in turbines and metalworking equipment does not seem applicable