LCP debur/smooth out holes?

[YME]

Building an Rv-12 and have agreed to accept LCP's labeled"acceptable for use" for my empennage kit, I have a question about the holes. I have inspected all the holes closely and want to lower the chances of any cracks possible forming later. After deburring is there any way of smoothing out the inside of the hole before installing rivets or dimpling. In doing so I would think it would lessen chances for cracks and the smoothing should not increase the hole size.

 

[nzrv8]

When I was having problems with dimple cracks on thicker skins (Pre-LCP), I found it beneficial to twist a little bit of scotchbrite around the end of a small drill bit (#50-ish) and run this through the hole to be dimpled with a cordless drill, polishing the inside. Works quite well.

 

[azonslow]

Building an Rv-12 and have agreed to accept LCP's labeled"acceptable for use" for my empennage kit, I have a question about the holes. I have inspected all the holes closely and want to lower the chances of any cracks possible forming later. After deburring is there any way of smoothing out the inside of the hole before installing rivets or dimpling. In doing so I would think it would lessen chances for cracks and the smoothing should not increase the hole size.

This is what section 12 empenage from 2013 at page 05-03 says:


All drilled holes, or prepunched holes that have been final-drilled to a larger size,should also be deburred. Holes that were factory punched to final size can beinspected and only deburred if needed (with the exception of large holes to be dimpledfor screws - see below). This is an easy but time-consuming chore, and can be donewith an oversize drill bit, either held between your fingers and twisted, or in a variablespeed drill running very slowly. Special swivel deburring tools are also available fromtool supply houses. These work better and are much quicker. Burrs around holes are a problem mainly in riveting and dimple countersinking. The burr can preventa rivet head from seating properly and can make dimple countersunk holes moreprone to developing cracks radiating from the hole. Many novice builders deburrexcessively deep. Deburring should not produce a significant chamfer/counter-sink on the edge of the hole. Be particularly careful deburring holes in .020 orthinner sheet. By the time both sides have been deburred the hole could be enlarged.