Drilling out rivets from alu sheet

[MBfreak]

At the tender age of 73 I have started a new career as a helpers helper at a airplane hobby club workshop. It is an ex SAAB shop and the tools and facilities are awesome.
Everybody except me have been APmechs for many years. I was invited to join to help out with electrical and electronics.
However I would like to learn a bit about restoring a seaplane made in aluminum. It was salvaged somewhere in the Carribean and at least 10 % of the airframe is corroded away. I have been told to start drilling out a lot af 5 mm rivets so that corroded panels can be removed and new ones made.
Anybody with knowledge, please share your tips and tricks.
My idea is to use a center drill after first having punched a very small dent in the center of the rivet head.
Minimum distortion of the panel and the structures behind is essential.

best regards

Ola

 

[ZRX61]

You're on the right track: center punch & drill the head off.
Are the regular rivets or countersunk?

Use one of those automatic spring loaded punches instead of the ones you hit with a hammer.


It's easy after the first 10,000

 

[RXtacy]

There are tools that help keep the bit centered around the rivet head. Works pretty well.
https://www.mcmaster.com/90112a600

 

[Kevin54]

A center drill will be the perfect tool. Use the appropriate size or just one size under. The beveled portion of the center drill will pop the head off when you get to the correct depth.

 

[cvairwerks]

Ola: With a little practice, there will be no need for center punching. Is the project US or European manufacture, as that will guide you in rivet size information.

They way I used to teach our newhires, was to use a #50 size bit to center drill the head of the rivet and learn to go just slightly deeper than the head, whether it was a flush or a protruding head. After center drilling, then drill to the same depth with the nominal hole size bit. With the bit still in the hole and the drill not turning, lay it over to the side and pop the head off. Now with backing around the buck tail to support the sheet metal, the rivet body can be driven out. It doesn't take a lot of force to drive it out, but should it not move, go back to the #50 and drill a bit deeper and try to drive the rivet out. Takes longer to describe the process than to show it. Most of the videos online show drilling with the same size bit as the hole, but it makes way too easy for a neophyte to enlarge the hole.

With some practice, it will become pretty easy to do. Just remember that the idea is to remove the rivet without changing the hole size. I used to drill for, and install hundreds of rivets every week, for many years, ranging from AD3's, all the way up to MS9035x blind fasteners in light sheet metal all the way up to fracture critical castings on Mach rated aircraft. Watch the other guys and you will learn all sorts of tricks and techniques.

 

[toolchaser]

CVairwerks is spot on , after a little practice you can steer the drill to the center like a pro without special bits. I drilled out thousands on DC-8/9, B727, L-1011 before I got tired of shavings in my shorts & became an inspector

 

[cvairwerks]

One thing I forgot to add... Start your learning with 6" bits, as they are much easier to assure that you are 90 degrees to the skin and rivet shank. Once you have the technique down, you won't have a problem going with jobber lengths in tight spaces, or switching to a right angle drill, or going with 12" bits where close access doesn't work well.

I'm assuming that you will be using an air drill, so trigger control is going to be part of mastering the process. Very slow speed to establish the start of cutting and increasing the speed to remove the bulk of the rivet while maintaining location. Sounds hard, but in reality, it's an easy skill to learn for anyone that has decent hand eye control and coordination.

You will have a blast, even with some frustration, but you will be able to look at what gets accomplished with pride.

 

[NC Rick]

Most guys used an air powered drill motor. High rpm and good control is important. My experience was with a 1/4" electric drill that runs 4000 rpm. Often, you can just get the head to come off and a small punch with a light tap will pop the rest out. Set rivets often have a dimple on the head. High strength blind rivets can be challenging.

Start on the most corroded part first. It sounds like you will be able to give lessons once your done.

 

[MBfreak]

Thanks for all info.
Reality starts om Monday!

Ola

 

[kctyphoon]

Look on YouTube. There are lots of videos about removing rivets..

There’s a tool for it -

 

[TLGriff]

Wish I had a penny for every one I drilled out.

Use a screw machine length drill with a split point and a high speed air drill to hold it. Drill only the depth of the head and tip the drill sideways to snap the head off, then punch the rest out (with a bucking bar next to the tail). Works the same for flush or universal heads. It takes some practice to find the center of the head, but the split point allows you to steer the drill around.

Tom