ASA (Air Standard Adapter) Dimensioned Drawings:

PDF
Cadkey Part File
DXF

Note that this is not any sort of canonical ASA drawing - it's simply based on measurements that I've made on various regs and tanks.  Many of the dimensions are rather flexible - an ASA makes an airtight seal not via the threads (like a 1/8" NPT connection) but by the o-ring at the top of the ASA.  Hence, the size of the o-ring groove should not be changed too much from what is shown.

Note that the ASA uses CGA 320 threads.  For more info on CGA 320, see http://www.concoa.com/frames/technical/cgaconn/cga320.htm

Also note that the drawing is meant to be used when single-pointing threads on a lathe - the drawing is not suitable for making a female ASA!  For female ASA threads, use a 1/2 NPS tap (that's a straight tap, not taper).
 

Fun fact: Tippmann invented the ASA...