Tank Attach Hardware

[Av8torTom]

Just being cautious here before I start drilling holes and countersinking.
There are two bags of tank attach hardware - 1922-1 and 1922. I assume the 1922-1 platenuts and screws are for the top and bottom spar flange as seen in the photo below:

Then I enlarge the platenut rivet holes, machine countersink #40, rivet platenut under spar flang, then machine countersink screw hole #30 on top of flange???

Sound right?

 

[Robert M]

Alrighty then! I have a slightly older kit and I don't have a bag 1922. I had a 1921 and 1922-1 both of which were tank attach hardwware.

My bag 1921 had 43 of the 10-32 platenuts, AN960-10L washers and AN3-4A bolts for attaching the fuel tank "Z" branks to the web of the main spars.

My bag 1922-1 had 212/213 of the K1100-8 CS platenuts and AN509-8R8 CS screws to attach the fuel tank outer skins to the main spar flange (for top and bottom).

That being said, yes, enlarge the platenut rivet holes with a #40 drill, machine countersink #40, rivet platenut under spar flange, then machine countersink screw hole #30 on top of flange. As I recall, the screw holes are already at the proper diameter and don't need to be drilled but you should put a screw through one to be sure. Also, don't forget to prime all of the countersunk holes when you get finished - it's a MUST on the main spar!

A good way to get the CS right for the screws is to use a piece of .035" scrap and drill a #8 screw hole in it, deburr, dimple with the #30 dimple. Use a #40 rivet to check the CS depth for the rivets.

Hope this helps....