MIL-STD-1913 MIL-STD-1913 3DDave (Aerospace) (OP) 8 Jun 17 15:48 Regarding MIL-STD-1913, I just came across this jewel. The document is available on http://quicksearch.dla.mil and the following should be a link directly to the page (saving having to type 1913 into the top search box.) http://quicksearch.dla.mil/qsDocDetails.aspx?ident... Is there any rule they managed to follow? Pay attention to the 1999 amendment to the section diagram. RE: MIL-STD-1913 JNieman (Aerospace) 8 Jun 17 16:00 Doesn't matter. Half the people alleging to manufacture "mil spec" pic rail commercially probably never actually read the MIL-STD-1913 doc anyways. RE: MIL-STD-1913 swertel (Mechanical) 8 Jun 17 16:04 We've tried machining our own Picatinny Rails based on the spec. You can't do it. Instead, we create our own drawing the closely follows MIL-1913, and then verify that our Rail actually fits the mating part before producing the full quantity. --Scott www.aerornd.com RE: MIL-STD-1913 pylfrm (Mechanical) 9 Jun 17 00:59 3DDave, In the 1999 amendment, are you referring to the "R 2X .060 MAX" being out of order? That's all I see changed. Regarding the rest of the tolerancing, I wrote up some of my thoughts in thread1103-406027: Seemingly incomplete tolerancing, reality check needed. Perhaps it will be of interest. pylfrm RE: MIL-STD-1913 3DDave (Aerospace) (OP) 9 Jun 17 03:47 Look at the datum references [-C-(m)] is not usual.