Mike, Note that there are K, L, and M designations for wall thicknesses of copper tubing.
Do K, L, and M apply also for aluminum tubing? Gene. ---- Original message ---- >Date: Fri, 30 Jan 2009 17:49:51 +0000 >From: "Michael Payne" <[email protected]> >Subject: [USMA:42628] Copper Pipe Sizes >To: "U.S. Metric Association" <[email protected]> > > I promised to measure the copper pipes I have in my > home, done with a micrometer at 20 C. > > 3/4" pipe is 22,2 mm OD. 19,9 mm ID. > > 1/2" pipe is 16,0 mm OD. 13,8 mm ID. > > 1/4" pipe is 9,7 mm OD. 7,9 mm ID. > > Seems like the wall thickness on this pipe is very > close to 1 mm. None of the inch sizes have any > correlation to the actual "nominal" size. Allowing > for manufacturing tolerances, these pipes are as > near to whole millimeter sizes as is possible. > > When you go into a hardware store and try to find > fitting that are labeled 1/2"or 3/4", etc. The > actual size bears no relationship to actual size > which can be very frustrating if you measured > something at home and expect this to match what they > have in the store. A 3/4" fitting from one > manufacturer will fit the 1/2" fitting from another > manufacturer, so each company is choosing any > definition they want for the named size. > > Mike Payne > >
