Shear panel attachment question

[Terry Oxandale]

When riveting shear panels to the chassis, is there any concern to the quality of the hole in the steel spaceframe structure? Specifically, when one drills a hole in the square tube, the backside of that hole will have a rough sharp edge to it. Will this flashing or rough edge (where the material has been "pushed through" during the drilling process) cause a problem with rivets, short term or long term?

 

[Pat Buckley]

Not that I have ever heard.

Of course you could drill the holes slightly undersize and ream to size if you don't want to take any chances!

 

[Howard Jones]

I have always drilled a pilot hole, or holes up to about 80% of the diameter of the final hole ID. This will insure that the final hole will be the correct size. in anycase I never start the 1st hole with anything less that 1/8". I believe it will also have a better ID edge finish. For a 1/8" diameter rivet I would drill a 3/32 pilot hole and then finish with a nice sharp 1/8 bit.

This is more important on larger holes such as those larger than 3/8 and necessary for 5/8 or bigger, but the principle still applies even for small stuff. You will just get a more accurate final ID this way.

I would also think that the "flashing" would be reduced with a 80% diameter pilot hole. I don't think the "flashing" issue is really a concern in the paneling application however.

 

[Terry Oxandale]

Thanks for the experience and advice.

 

[Scott Calabro]

Really sharp (New) high quality drills are the best answer on holes that small.

I've drilled a lot of blind holes in airplanes my 26 years

You could try this tool;
Brown Tool - Cart: 1351306

Or here;
http://www.deburringtools.com/deburringblades.html

Not quite sure it will go in a 1/8 hole though.

What you are talking about is really a non-issue IMHO as the blind rivet fills the hole as it gets squeezed, plus the little burr will just get squeezed over as well.

Cheers,
S

 

[Jack]

should you deburr, the swarf will fall into the tube anyway. Use a sharp drill bit & Scott's statement about the rivet capturing the burr is correct.

Jack..

 

[Terry Oxandale]

Thanks for the answers. My initial concern was, say perhaps, the "flashing" is squeezed into the rivet (aluminum rivet assumed here) as the rivet is installed, which prevents the rivet from fully and completely seating against the base frame steel (rather than the rough edging). Then after so many hours of vibration (much as a solidly mounted motor eventually seems to work every fastener loose that is not safety wired), this sharp material digs into the rivet eventually causing them to lose the tension on the panel.
Perhaps I'm over-analyzing this whole issue.

 

[Russ Noble]

If you bond and rivet, then the rivets really only hold the panel in place until the bond cures. Should not be a problem.

 

[Ardern Cars]

Scott,
Thanks for those links. Good stuff.
Chris

 

[RobGT]

Would it be a good idea to wet assemble panels anyway, to prevent water and the likes get in, also prevents rivets coming loose and nasty rattles.

O/T, what kinda aircraft do you work on Scott? Im a rigger over here in the UK.