F-637 Seat back assembly riveting Q

[flydjd]

Hi all,

For the seat back assembly, has anyone used AN426-AD4 rivets for the 7 rivets (not incl. the 2 for the angle braces) that attach the F-637D upper hinge (for the F-638 seat back brace) to the seat back instead of AN470-AD4's ?

A couple of reasons for asking

1. Do the heads of the 470's cause back discomfort if thin seat cushions are in use ?
2. Easier to back rivet these 7 before riveting the rest of the seat back assembly together (and looks neater)

Thks

[thallock]

David,

For those rivets to give you discomfort, you would have to have the cushion compressed down to 1/16 to 1/8 of an inch, in which case, you are going to have discomfort anyway. I just finished this last week, and I considered putting the shop head FWD, so the normally visible rivets on the AFT side of the seat would look nice. Then I thought this was retarded, so I did it normally, with the manufactured head FWD. I suspect that if your seat cushion is so thin, the side rails would give you more discomfort.

Tracy.

[flydjd]

Hi Tracy,

Thanks for answering point 1.....

Did you give any thought to backriveting ?

[thallock]

David,

Yeah, when I was building the seats, I though that those rivets were going to need to be flush and back-riveted. But, then when I got around to finishing off the seats, the plans showed everything as AN470's, so I shot them with a rivet gun. Not that bad, just clamp the seat backs to the bench real good.

I just made a couple of practice seat cushions for the seats this weekend, and the seat backs really don't need much foam. I used an old bed top foam, about 2" thick, with egg crate on one side. Seemed pretty comfortable, and there's no way you are going to feel the rivets through the foam. The final seats will probably be 2" flat foam. I found some this weekend at Hancock Fabrics, that was flame resistant.

Tracy.

[alpinelakespilot2000]

Originally Posted by flydjd

Hi Tracy,

Thanks for answering point 1.....

Did you give any thought to backriveting ?

You should be able to squeeze these AN470 rivets no problem, especially if you have a longeron yoke, but even a normal 3" yoke should work just fine. For what it's worth, I put the shop heads forward, rationalizing that they'd be covered up by the cushions but my hands would touch the back of the seat often, so I wanted the smooth factory heads there. No reason you couldn't use AN426s here either though if you really are concerned about them being flush. All preference, I'm sure.

[flydjd]

Hi all,

Thanks for the replies.....i am just going to go with the 470's .....everything else is done for the seats......now i just need more practice with my least favourite tool !