Cogsdill Deburring Tools

Many RV builders ask about the Cogsdill Deburring Tools for 3/32 and 1/8 inch rivet holes in their airplane projects. The RV tool kit does not include these deburring tools. The reason for this is that the rivet holes can be easily over-deburred with these tools. This causes the cleco temporary fasteners not to hold after the rivet hole is countersunk. For a better explanation of this issue see the link in the title of this writing.

Most RV tool kits are based on Van's Aircraft recommendations. Van's often over-emphasizes the deburring of holes on the RV airplanes. The fact is that unless you are building a pressurized aircraft you do not need to worry about having perfect rivet holes. A hole drilled with the appropriate aircraft drill bit and wiped off to remove any burrs is adequate.

Deburring does not mean having round and smooth holes, only removing burrs -- if you do not understand what a burr is, consider it a hang-nail inside of the rivet hole. If you don't have any of these "hang nails" then don't deburr. Your airplane will look highly professional and you will be glad your clecos all held in place after you dimpled your parts.