Replacing Rivet with AN3 bolt.

KMinor · #1 08-18-2012, 02:19 PM

After grabbing the #12 instead of the #21 drill bit, and over widening an already widened hole, I find myself having to use an AN3 bolt in the place of a AD4-4 rivet in my rudder interior structure (as recommended by Van's). Can someone tell me if I should or should not use washers? Do I only use them to ensure proper grip length? If a bolt and nut only fit then is that all I should use? Thanks in advance.

cfiidon · #2 08-18-2012, 02:24 PM

You would want to use at least one washer under the nut so that it does not score when you tighten it down.

Don

Walt · #3 08-18-2012, 03:24 PM

It may be ok, but one should not assume that's it ok to always replace a rivet with a bolt just because they made the hole to big, things like material type, material thickness (minimum thickness for use with AN3 is .040"), edge distance etc. all come into play.

KMinor · #4 08-18-2012, 05:46 PM

Thanks for your responses. I noticed in other places there is usually a washer under the nut, so I think I will use one here. I was going to try to set a 3/16 rivet, but was worried about the edge distance so I sent pictures, etc. to Van's. I was told that the rivet could cause distortion here and that a bolt (AN3-3A) was better. It is where the rudder tip rib meets the spar flange and there are two rivets there. Thanks again!

alpinelakespilot2000 · #5 08-18-2012, 06:59 PM

The rivet you messed up is easy to mess up, so don't get discouraged.

Since you are early in your build, I might recommend you get familiar with oversize Cherrymax pulled rivets. Aircraft Spruce carries them and their page has a chart showing what size you would need based on the thickness of the layers you're riveting. These are very handy when you bungle up an AD4 rivet and drill it out leaving the hole just a tiny bit larger than it was originally.
http://www.aircraftspruce.com/catalo...cherrymax4.php
Note that the "CR3242 and CR3243 are oversized diameters and measure 1/64" more than listed diameter," so you'll need a bit larger than a #30 drill in order to clean up the whole before setting the pulled rivet.

And, yes, washers are always used under a nut. I can't think of a single exception to this.

Hope this helps, and good luck.

N941WR · #6 08-18-2012, 07:12 PM

Quote:

Originally Posted by KMinor

Thanks for your responses. I noticed in other places there is usually a washer under the nut, so I think I will use one here...

Just remember, you should always tighten the nut, not the bolt.

KMinor · #7 08-18-2012, 08:52 PM

I thought about Cherrymax because the guys at our hangar use them alot on our helicopters, then I decided to just let the folks at Van's tell me what to do. I'll research them and probably get some to have around just in case. I thought I'd gotten pretty good at drilling out rivets. I'm starting to see the light at the end of the tunnel on this empennage and I think my confidence got ahead of my ability! It's good to be humbled and reminded to slow down, especially with that dang trim tab coming up soon!
Thanks some more guys!

drakerv · #8 08-18-2012, 11:57 PM

Why Not a Hi Lok ?

KMinor · #9 08-19-2012, 07:49 AM

Didn't know about Hi-Lok before now. It looks like just what I need. Trying to figure out which one to use is intimidating, though. Titanium or steel, shear or tension, 95 Ksi or 125 Ksi. I'm tempted to use the steel just because it sounds comparable to the AN3 bolt, and I'm sure I don't need it to shear here. Then you have to match a collar to it... Any advice for a novice? I'm waiting to fill in this one hole so I can close up my rudder, but am not in any hurry because I've moved on to the elevators. So if hi-lok is the best option, I'll put the AN3 bolt in the bin and wait for another order to come in!

az_gila · #10 08-19-2012, 08:02 AM

Quote:

Originally Posted by KMinor

Didn't know about Hi-Lok before now. It looks like just what I need. Trying to figure out which one to use is intimidating, though. Titanium or steel, shear or tension, 95 Ksi or 125 Ksi. I'm tempted to use the steel just because it sounds comparable to the AN3 bolt, and I'm sure I don't need it to shear here. Then you have to match a collar to it... Any advice for a novice? I'm waiting to fill in this one hole so I can close up my rudder, but am not in any hurry because I've moved on to the elevators. So if hi-lok is the best option, I'll put the AN3 bolt in the bin and wait for another order to come in!

Go with the AN3 bolt solution. It's the quickest and easiest and will do the job...