About to start on the empennage horizontal stabilizer for Sling TSi, and curious what others have done for deburring? While inspecting a few of the parts the long edges don't seem to have burr's, with perhaps a few in the rounded corners of ribs, etc. What level and/or process of deburring have others done right out of the crate?
Re: Deburring
Posted: Tue Dec 10, 2019 10:35 am
by PhilipRueker
To check what needs deburring - you want to run your finger over the holes and the edges.
If it feels rough, then you want to give it a quick deburr, but you don't want to overdo it.
For the holes particularly, if you're using a circular deburring tool like https://aircraft-tool.com/shop/detail.aspx?id=AE1046 you should only do one-two quick turn or else you're actually going to countersink holes.
Most of time time, only one side will need deburring since the burrs are typically on the other side that the automatic machines punched/drilled through.
From my experience so far, often times some parts don't need any deburring and then every now and then there's a part that has a bunch of rough edges, so just have your set of files, deburring tool and sanding paper handy.
Here's also a quick video from HomebuiltHelp on deburring:
One other aspect along the lines of deburring is the avoidance of sharp inside corners (which is why corners are always rounded out) to reduce Stress concentration (https://en.wikipedia.org/wiki/Stress_concentration) - A straight 90 degree corner on the inside invites stress and can/will lead to cracking, which is why you will see that edges are always rounded out.
For some more official guidance for airplane building/repairs, you can refer to AC43.13 which will call for rounding out any corners to prevent stress. https://www.faa.gov/.../Advisory.../AC_ ... w-chg1.pdf