SAE and metric equivalents

[Yankee]

I've been curious if the 5/16 (8mm) 3/4 (19mm) and. 1 1/16 (27mm) wrenches are actually the exact same wrench just stamped different by manufactures or if some manufactures actually have a seperate mold for each to stay in an exact tolerance. I've got craftsman industrial wrenches and on fasteners I can't tell the difference even in the slightest. I don't have a micrometer to check, but curious if other brands were the same. (I do realize the tolerances are close, just curious if there were any manufactures that don't cut corners and still make different wrenches)

 

[Yankee]

I'm guessing Craftsman doesn't since that would explain why some sets skip sizes. (If you get the other set (metric or SAE) that equivalent is there)

 

[Wakefield]

WrightTool catalog has a chart that appears to indicate sizes where a metric can substitute for a SAE or vice versa. I suspect that some tool companies use the same wrench to stamp 3/4" or 19mm. on but that is sort of cutting a corner. 11 mm.socket seems to fit tighter (better) on a 7/16" hex Tecumseh muffler bolt than a real 7/16" socket. Both 12 point Wright. The 7/16" is a little bit shorter than the 11mm. Both deeps.

(really ought to use a 6 point not a 12 point on that muffler bolt if rusty on underdeck muffler getting removed)

 

[OutsideMachinist]

Some are so close it wouldnt really matter what the manufacturer is. But yes generally the cheaper brands have bit more slop in them.

http://www.hamuniverse.com/antfrac.html