AN470AD4.5 rivets?

[maniago]

So I cracked a stringer on my Mustang and have to replace it. 40 some odd 470s to drill out.

I've heard there are 4.5 dia rivets ie 9/64 in dia (.140) vs standard .120. Aircraft Spruce has had them in the past but doesnt now. Also nothing in Vans List. I'd like to not use 5s as they are a pita to buck in blind areas and thats what I have to do.

Anyone got any ideas where to find them and more importantly, what their nomenclature is? (note these are 470s, not 426s so NAS1097s are a non starter)

Thanks for any info.

[rv7charlie]

Hi Mani,

Mustangs are fine a/c; I've flown several & actually had a kit for about a decade, but it wasn't a 'building decade'. Finally sold it to keep it from corroding away, & later started my -7.

One thing you might experiment with is to try 'pre-squeezing' some longer 4s to make them swell up a bit prior to inserting them in the holes. It's a bit tougher to do that with universal head rivets, but not impossible. If your drill job is done even 'fairly' well, you might find that you don't even need bigger rivets. Have you seen the instructions floating around the 'net on how to drill them without oversizing the hole? You can get a centering tool that will start the bit in the center of the head (assuming an undamaged shop head) and drill with a 3/32 bit until you're 1/2-3/4 through (this releases most of the spreading force in the hole), then use a larger bit to drill off the head. A 3/32 punch can then be used to punch out the remaining shaft/shop head.

If you have poorly formed heads, you can 'shave' them off flush with a rivet shaver tool, then it's easy to see the shaft. Drill with a 3/32 as above and punch it out.

FWIW,

Charlie

[maniago]

Thanks Charlie. Yes I got the skinny on drilling out rivets - had my fair share of practice so far, so I'm not too worried that I'll over size getting them out.

My problem unfortunately, is matching the existing holes - the stringer is curved and it rides on top of the exisiting holes - alignment is blind and inaccessable to any angle drill or marker from behind etc. I'm pretty sure I can dupe strap about 50% - the others are gonna at best be measurement and hope. Its inevitable that some of those if not all will be off enough to require larger rivets.

I'll get it done, but exploring the rivet size option is better than going to all -5s. Squeezing rivets prior to using the gun is an interesting thought and I'll noodle through that. Thanks.

[Charles in SC]

Can you get to the factory head to drill, I have a tool that centers the drill on the factory head. I got it from Aircraft Spruce, it works great.

[Dave62]

The rivet you need is NAS1242AD4-whatever length you need. Google and they are available from several suppliers
Dave

[GAHco]

We have these oversize rivets typically

[maniago]

Excellent guys! NAS1242AD4 Exactly what I was looking for.

Thanks a bunch!