When metal is cut with a CNC router or laser the edges are sharp. These edge finishes that are sharp are referred to as “burrs”. All parts need to be “deburred” before they are assembled. This is a very important step because a burr can lead to deterioration in the metal due to abrasion over time. Burrs or sharp edges can also cause skins to dimple, resulting in a skin that doesn’t lay right or has bulges in it. Rivet holes that are not properly deburred can result in a rivet that doesn’t pull tight, sits proud and/or degraded sheer strength due to improper fit. Abrasion over time between burrs left between two sheets of metal can result in structural failures.
There are many choices of tools to use for deburring parts, depending on the part.
Edge Deburring
Edge deburring is the task of running a tool along the edge of the part. Examples would be ribs, spar channels, lightening holes and skins. Tools commonly used and recommended for this task are:
•Sand paper
•Multi-burr tool (hook type blade that swivels with a handle)
•Metal file
•Dremel attachment
Edge of Flange Deburring
The corners of flanges at the radius need to be knocked down. An example would be a nose rib. Using sand paper, a dremel attachment or your belt sander, gently knock the sharp edge off. See photos for more information
Hole Deburring
After each hole that is going to be riveted, bolted or screwed to another piece of metal is up-drilled or reamed to the proper size needs to be deburred before final attachment. Each side of the hole has to be deburred!
IMPORTANT: The goal is to remove the burr. Do not press too hard and create a chamfer in the holes. This will result in an oversized hole and cause the hardware to fit loose.
Deburring holes can be done with a simple large drill bit head, by slowly and gently turning on the face of the hole. Or a rose bud drill bit attachment can be used. There is also a drill attachment called the “burr-away”. This attachment needs to be used with a multi-speed drill on the slow setting. The burr-away tool is a shaft with a small, spring-loaded blade that spins. When pressed against the face of the hole the blade shaves off the burr. When you push through the hole the spring-loaded blade retracts. You then pull the tool back through the hole and the opposite side gets deburred on the way back through.
