Hardware Identification

Here is a PDF from the FAA that has some great info about hardware identification

An article about AN Hardware  by Ron Alexander of Alexander SportAir Workshops


Here's a PDF with a Tap and Drill chart


AC 43.13-1B  ACCEPTABLE METHODS, TECHNIQUES, AND PRACTICES - AIRCRAFT INSPECTION AND REPAIR
or
http://www.moneypit.net/~pratt/ac43/

Torque Spec for AN Bolts
This Chart is from Chapter 5 of the building manual from Van's.

** PLEASE NOTE: These torque specs are the torque that you use AFTER overcoming the friction torque (call it "Torque Drag" or there are other names) of the bolt going thru the fastener. (i.e. if it takes 4 in/lbs of torque just to turn the AN3 bolt thru a nyloc nut, then add 4 in/lbs to the final torque requred, which will now be 24-29in/lbs)

*** NOTE: DO NOT tap nutplates to reduce torque required to turn screws. (At least on all structural fastening) They are designed to lock screws.
Fine tread series, standard type nuts ( MS20365, AN310, AN315)
AN Bolt Size Bolt Size -
Threads per inch
Torque Required
Inch/lbs
Torque Requred
Foot/lbs
AN3 10-32 20-25 inch/lbs 1.6 - 2.0 ft/lbs
AN4 1/4 - 28 50-70 inch/lbs 4.2 - 5.8 ft/lbs
AN5 5/16 - 24 100-140 inch/lbs 8.3 - 11.6 ft/lbs
AN6 3/8 - 24 160-190 inch/lbs 13.3 -15.8 ft/lbs
AN7 7/16 - 20 450-500 inch/lbs 37.5 - 41.7 ft/lbs
AN8 1/2 - 20 480-690 inch/lbs 40.0 - 57.5 ft/lbs
AN9 9/16 - 18 800-1000 inch/lbs 66.6 - 83.3 ft/lbs
AN10 5/8 - 18 1100-1500 inch/lbs 91.6 - 125.0 ft/lbs