Many auto manufacturers use only a few common sizes. I used to own a 1964 Volkswagen Beetle (bought used in 1971 and kept for five years; I did all the work including overhauling the engine) and I could pretty much do anything with just a 10 mm and a 13 mm wrench. There were one or two larger bolts/nuts but those were by far the most common.
Carleton ----- Original Message ----- From: "Bill Hooper" <[email protected]> To: "U.S. Metric Association" <[email protected]> Sent: Friday, March 5, 2010 12:02:59 PM GMT -05:00 US/Canada Eastern Subject: [USMA:46843] socket wrench sizes I saw two sets of socket wrenches at the auto store recently, one YOE (Ye Olde English) on on SI (metric). Here were the sizes, in random order: Ye Olde English 3/4” 5/8” 9/16” 7/16” 1/2” 3/8” 5/16” Metric 13 mm 10 mm 14 mm 9 mm 17 mm 12 mm 15 mm It's an interesting exercise to have someone try to put each set (separately) in order, smallest to largest. Even better might be to actually obtain such sets of sockets or other wrenches and, after mixing them up, ask someone to arrange them in order. I've always argued that this is one example of how SI beats YEO but this is the first time I've actually found a real set of real tools so that I know I am using a realistic example and not just one I made up. (I'm not a "tool guy"!) I found it interesting that the metric set was "missing" an 11 mm and a 15 mm socket (missing from a completely uniform set of steps - 1 mm each step). I also note that YOE was missing the 11/16" size (from a completely uniform set of steps - sixteenths of an inch). I like to fiddle with numbers so here are some other lists and comparisons of these same values. Here is a list of the combined YOE-SI wrenches, in order: 5/16” 9 mm 3/8” 10 mm 7/16” 12 mm 1/2” 13 mm 14 mm 9/16” 15 mm 5/8” 17 mm 3/4” It's interesting that they alternate except for the one example were two metric (13 and 14 mm) sizes fall between two YOE sizes (1/2" and 9/16"). Here is the same list with all sizes converted (where necessary) to millimetres for ease of comparison: mm 7.94 9.00 9.53 10.00 11.11 12.00 12.70 13.00 14.00 14.29 15.00 15.88 17.00 19.05 and here it is again, this time with the numbers rounded to whole millimetres, except where doing so would show a YOE size as if it were exactly equal to an SI size: mm 8 9 9.5 10 11 12 12.7 13 14 14.3 15 16 17 19 I think it is interesting that there is no size of about 18 mm in either set. Bill Hooper 1810 mm tall (Bigger than the average socket wrench) Fernandina Beach, Florida, USA ========================== SImplification Begins With SI. ==========================
