I recently did some research into the subject of removing rivets that are used to fasten the exterior and interior panels together. Here are my findings.
The exterior aluminum panels are fastened together using 5/32" buck rivets. They are installed by placing a piece of metal, called a "bucking bar", behind the rivet and compressing them with a special tool. So-called "pop rivets" (also referred to as "blind rivets" use a metal shank that pulls the back of the rivet causing it to mushroom when used with the installation tool, thus keeping everything in place.
Neither type of rivets are reusable. In order to remove them they have to be drilled. This is not too complicated a procedure in itself but removing rivets especially from the outer shell must be done with great care and attention; otherwise you may risk damaging the Alclad aluminum plate should the drill slip and move while you are drilling. You may also enlarge the hole which could lead to waterleaks later.
The traditional method is to use a spring-loaded center punch, such as the Starrett #18-AA or Stanley model #1113 to create a dimple in the head of the rivet. Then carefully drill into the dimple you created using a #21 drill bit until the head comes off.
I found a couple of very useful rivet removal tools used in the aviation industry that are available to make this procedure much simpler and less stressful. Several companies sell them and they're all pretty much the same except for one manufactured and marketed by a small company up in Michigan named Aircraft Tool Supply (ATS). This tool, P/N 1341S offers an important feature that the others lack - More about this model later.
The rivet removal tools come with four cobalt-tipped drills and matched nosepieces in the following sizes: #40 (3/32"), #30 (1/8") (as used on the interior panels), #21 (5/32") (as used on the exterior panels) and #12 (3/16"). You can adjust the depth of the drill stop which means you will only drill as deep as necessary to remove the rivet head which is a very nice feature. Drill sizes are as used in the aircraft industry and the fractional size equivalents are approximate.
All the rivet removal tools are precision items but the standard model is really only suitable for buck rivets that tend to stay in place when drilled whereas the ATS 1341S works well with all kinds of rivets. I found it easy to use and was able to remove several rivets cleanly and quickly, using it with my DeWalt 3/8" cordless drill.
Sometimes the the torque of the drill may cause a rivet to spin. This can make the task more difficult and increase the potential for damage to the aluminum plate. The difference between the models is that the ATS P/N 1341S features serrated nosepieces that grip the rivet head and keep it from spinning as it is being drilled. This is more likely to occur when working with pop rivets but any rivet being drilled has the potential to spin. In my opinion it's well worth the additional cost to have the serrated nosepieces in case this happens.
Unfortunately, none of these rivet removal tools come with any documentation such as instructions for use. Perhaps it is assumed that anyone requiring this tool for use on airframes is familiar with its use. However it is pretty simple to figure out and I was able to make the following notes on how it is used.
The tool must be set up with the matching drill and guide as selected according to the size of the rivet shank you are removing. At the top there is a shank that goes into your drill's chuck. Unscrew this piece and remove it from the sleeve along with the spring. Install the correct size drill. Set aside. Unscrew the nosepiece and separate the locking
ring from the nosepiece. Now screw the top part containing the drill into the sleeve. You will notice that the shank and drill are spring-loaded. Select the nosepiece that matches the drill you previously installed. Screw on the knurled locking ring as far as it will go. Install the nosepiece that matches the drill size you are using. Slide the nosepiece over
the drill and screw it into the sleeve. It is at this point that you will adjust the depth stop feature keeping in mind the preset distance for drill travel is 1/4". Finally use the knurled locking ring to lock the nosepiece to the sleeve.
Once the tool is properly set up it is a simple matter to remove rivets quickly and safely. Just insert the shank into your drill's chuck and tighten, remembering to make sure there's about 1/4" travel room when the spring in the tool is compressed. Place the nosepiece over the rivet.
Holding the tool's knurled sleeve with one hand operate the drill with the other and press down on the rivet drill until the tool reaches the preset stop. The rivet head will fall off. It's that simple.
My conclusion are that both models will work perfectly for drilling the 5/16" exterior rivets. However if you feel you will be dealing with the 1/8" internal pop-rivets as well you should consider the additional $20.00 for the 1341S model a worthwhile investment.
For more information go to www.aircraft-tool.com
and search on 1341S.