Deburring holes

[Frank]

It was suggested to me that deburring drilled holes should not be done with a deburring wheel (2024 T3). This is important consideration because I still have a LOT of deburring to do on the wings and elsewhere. I plan to etch and paint parts before assembly, if that mitigates any problems.


But here are the comments: "The alclad has been removed with the deburring wheel. Putting a fastener(dissimilar metals) through the hole will cause corrosion in the area over time.” And even though I will use solid aluminum rivets on aluminum parts, "It is not the aluminium itself that is the problem but the alloys used.”

Bottom line, can I continue to deburr with the Scotchbrite wheel and pads, or should I strictly use deburring tools?

Screen Shot 2021-09-27 at 2.14.32 PM.png

[noema]

I doubt there is much galvanic corrosion between different aluminum alloys. They usually all fall within a 250mV delta in the galvanic series. On the other hand the whole point of alclad is to sandwich a fatigue resistant alloy between two thin layers of corrosion resistant alloys. Sanding off the outer layers makes the piece more corrosion-prone.

[Lee]

I use a this tool in a cordless screwdriver. Works like a champ. One revolution only. Got mine from Clveland Tool: https://www.cleavelandtool.com/produ...deburring-tool
Lee

[Sir Newton]

Strictly use the proper tools. :-) The holy Bible of AC-43 Deburring controls cracking. ;-(

[Frank]

Preponderance of opinion (Facebook groups Bearhawk Builders Support and Aviation Sheet Metal) is that one should not deburr holes with the abrasive wheel. The corrosion issue may or may not rear its ugly head. Expert opinion varies slightly. Using Stewarts Ekoprime on these parts will certainly help in this regard. Nobody said my parts are ruined, just that is not good practice to remove excess material just to get a smooth edge to the hole.

Also, a sharp drill bit should be used with a back-up block whenever possible. It’s true I did force the drill through in many instances.

So I will proceed to clean these parts with detergent, then etch with Ekoetch, then prime with Ekoprime. Then assemble with rivets.

For the next round of drilling and deburring I’ll change methods. I have a basic bit and deburr tool from AS. To me it seems the ideal deburring bit will have a flatter angle than I have tried so far.

I like the suggestion to use a countersink guide which might offer dependable control over the bevel, which was my problem with both countersink and ‘dog leg’.

[Sir Newton]

I use a drill bit that is couple or three sizes bigger then the hole I am deburring. Simple cheap effective

[rv8bldr]

I used this for my RV-8 and the Bearhawk I'm building. This one is on the ATS site, but I got mine from Avery Tools years and years ago. Absolutely dead simple to use and does a great job.

deburr.png

[noema]

This tool is compatible with all the avery countersinking bits. This is useful when the stop cage is too bug. Extension also mounts into a drill chuck decently well. Good for countersinking hard to reach areas.

[nborer]

I use the same thing, and many of the old-time A&Ps I worked with on CAF aircraft did as well. One or two turns does the trick.