There is a 1/4" at the end of the thread that is .374" and the hole in Vans bracket is taped to 1.5" deep using a 3/8" 16 Pulley tap and then Counter bored to 3.75 inches about 5/16" deep for the tail cone and on the wings they have a two step shank 7/16" 3/8" deep and the .374"1/4"deep to allow them to be in contact with vans Brackets and not contact the wing skins
Also I have chamfered the hole, However I use S hooks at the end of my tie down ropes
Originally Posted by EXflyer
I see no radius at the base of the threads it should have one there and another thing is the sharp root of the threads will be a weak point. If you notice the tie down ring shown it has rolled threads with no sharp root. Also if one uses a thread lube such as copper coat on the threads will take care of things.