[USMA:48353] Re: Fw: Why no 18 mm Sockets or Wrenches in Standard Metric Sets

[John M. Steele]

My open-end wrench set and my half-inch drive socket set both include 18 mm (I checked), so I can't relate to the statement they aren't sold here.  In ANSI/ISO thread spec, 18 mm is the A/F (across flats) head size for a 12 mm bolt.  In the DIN and JIS standards, 18 mm is not used, they jump from 17 mm to 19 mm.  It might depend on where the set was made, and screw standard they assumed.

 

Both sets mentioned above are Craftsman brand, so Sears is one possible source.  Also, it is possible to buy individual sockets and wrenches for sizes not included in the sets.

 

PS: American cars are pretty metric.  An occasional US fastener may be found on a purchased module or subassembly, but I doubt you would find many installed by the OEM.

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From: Paul Trusten <trus...@grandecom.net>
To: U.S. Metric Association <usma@colostate.edu>
Sent: Wed, August 11, 2010 3:03:23 AM
Subject: [USMA:48350] Fw: Why no 18 mm Sockets or Wrenches in Standard Metric Sets

Randy,  I am posting your question to the USMA listserver, and I'm confident that one of our list subscribers will have an answer for you and reply to your question.

 

Paul

----- Original Message -----

From: Randwulf Technologies

To: Paul Trusten

Sent: 10 August, 2010 11:45

Subject: Why no 18 mm Sockets or Wrenches in Standard Metric Sets

Dear Paul,

I have a question my father asked about metric. Here in the US socket and wrench sets are sold without 18 mm, yet my father needs that a lot to work on various machines. I checked my own set and indeed it goes from 17 to 19 mm with no 18 mm. I had a friend who claims it was to keep Americans from using certain sockets on American (non-metric) cars and stripping them out. If you have any idea let me know.

Thanks,

Randy

--
Randy Bancroft   P.E
Randwulf Technologies
2837 Perry Street
Denver, CO  80212
Cell (303)-507-9889
www.randwulftech.com