Removing right baggage floor on a 9A - aft rivets to bulkhead?

This is a question about whether we need to figure out a way to remove some rivets... We bought our 9A already flying, and the passenger step cracked a while back. We've just started the replacement process. The part numbers that follow are from drawing 29.

We started by drilling the heads off the pop rivets of the right baggage floor (F-747-R) and drilling out the heads of the flush rivets that hold the floor and inboard baggage rib (F-727-R) and nut plates together. A couple of the rivets are still holding, so we decided not to push it with too much drilling and wait for reinforcements (i.e. experienced folks) tomorrow or the next day.

Meanwhile, after taking off the baggage bulkheads, we saw that the flange on the aft end of the baggage floor is riveted to nut plates and the fuselage bulkheads (F-706-B and F-706A-R) with about 15 flush rivets. Is it possible to access the area below the baggage floor without removing these rivets? (They're a little hard to see in the photo, because everything is gray.)

Rivets

Nope! All the rivets holding the floor to the ribs and bulkhead have to come out. Solid rivets are easy, although not quite as easy as pop rivets. Use an automatic center punch to enlarge the dimple already in the head of the flush rivet. Use a 3/32" drill to drill into the head. To remove properly, insert a 3/32" punch into the hole and snap the head off. Then use the punch with a backing bar behind the bulkhead to drive the rivet shank out. If you're in a hurry, you can just drill all the way through the head and shank. The "proper" method ensures you don't enlarge the rivet hole. Not too important when the rivets are just holding the nutplate on.

Me too

I just started a similar process on the -9A that I built. Drilling out rivets is lots of fun. Did your step crack on the inside with little or no abuse by large passengers?

Quick question to the group. When re-installing all of the nut plates, can they be flush riveted to the inner structure so they won't have to be drilled out again?

Thanks terrye, but sorry to hear that. So...if those rivets have to come out, is there a good way to get a drill bit on them perpendicular to the rivet head? The rivets are so close to the floor, the width of the drill itself is a problem. I'm using a cordless Ryobi drill (for now - I could see what tools are available to borrow).

JohnInReno - just a light passenger and no abuse. Cracked on the inside at the weld.

Drills

There are several ways to drill in tight quarters such as the floor flange:
Cheapest:
12" long 3/32" or #40 drill bit in a regular drill motor. Bend the drill bit as required to get in close to the floor.
http://www.cleavelandtool.com/12-Cobalt-Drill-40/productinfo/DBC1240/#.VVlV3JXbJaQ
http://www.aircraftspruce.ca/catalog/topages/12drillbit.php
More expensive:
90 degree attachment for your drill motor:
http://www.cleavelandtool.com/Angle-Drill-Kit/productinfo/ADAKITW/#.VVlWx5XbJaQ
Check diameter of head to ensure clearance
Really expensive:
90 degree small head air drill motor
http://www.cleavelandtool.com/Taylor-90-deg-Angle-Drill/productinfo/ADAT50/#.VVlXEZXbJaQ
http://www.cleavelandtool.com/Sioux-90-Degree-Drill/productinfo/ADAS1551/#.VVlXO5XbJaQ

Leave the back rivets

I was able access the passenger step by leaving the rear bulkhead rivets and rolling the floor up out of the way. A little safety wire will hold it out of your way while you work.

If you have a slider, it is easy to remove the canopy for better access.

If you mess up the floor sheet it is not a lot of money to buy a new one. I had to buy one about a year ago, I think it was about $27. The reason I took mine out was to add some wiring runs.

That is good to hear about the possibility of rolling the floor up. We'll try that first...!

Rolling floor

Learning to post pictures but here is a link:

You can take a dremel with a cutting disc and cut off the shop head of those rivets (on the aft side of the bulkhead). Then you should be able to pop them out with a center punch from the back. I have removed many a rivet in a tight spot this way.

Chris

We ended up removing the baggage floor completely, rather than trying to bend it up and out of the way. My builder friend used a Sioux air drill, which has a narrower profile than the cordless drill, and he was able to get the heads off the 15 flush rivets in a couple of minutes.

Then, using a small, modified cutter (about the size of a mini-pliers), removing the shop heads and the center of the rivets was easy.