Heres one for O'scopes from Tektronix:
http://www.tek.com/Measurement/App_Notes/XYZs/
and heres one for VOMs (Multimeters):
http://www.svconline.com/mag/avinstall_dont_guess_vom/
and on winding transformers:
http://www.geofex.com/Article_Folders/xformer_des/xformer.htm