Over the years I’ve found so many incorrectly fitted screws, type, size and length, I hope people find this helpful. I know some holes for the self-tapers get enlarged and need a larger screw, but it is usually due to someone in the past not having the correct screw and going one size up, honeycomb being so easy just to screw into. Just one of my pet hates.

Self tapping screw p/n’s in the IPC. For example AES1021A4-6

AES, GAES, AGA, TAES, means nothing, I think it’s just the manufacture’s (A) American, (GA) Grumman American,  (AGA) American General Aircraft),  (TA) Tiger Aircraft),   (E) engineering (S) spec.

,

First 4 digits
1021  Truss (Mushroom)Head
1022 Flat (Countersunk) Head
First Letter.
“A” Gimlet Pointed Self Tap. (Type A)
“Z” Blunt Pointed for use with Tinnerman nuts. (Type B)
Next digit. Screw size, followed by Screw length in 16th of an inch.

Kind Regards

Ian Matterface
Matair
http://www.matair.co.uk
Tel + 44 (0) 7751 257666
I can also be Skype’ed using “grumpyparts”