Deburr Thick Aluminium

[RVG8tor]

Please excuse the question from the new builder. But nothing I have read addressed my issue. I was deburring the VS main spar doubler (very thick). I was working the lightening holes, with a 1 in scotch bite wheel. The edges felt smooth but when you look at the area there are low and high spots from what looks like the forging process.

My question is do these parts need to be mirror smooth or is smooth to the touch work. Also while deburring my wheel slipped and I managed to scratch the flat surface of the doubler, deep enough that a red scotch brite pad does not remove the scratch, am I correct is assuming that I need to sand these scratches totally smooth. On my edges of the thick material I used a vixun file to get the high spot off, then the wheel to smooth things out.

Thanks for the help, any books with pictures that show what is good and band deburr practice. I took a fundamentals class but we did not deal with thick aluminium like the VS doubler.

Cheers

[bullojm1]

Mike,


Do yourself a favor and pick up a dremel (or knockoff, I have the sears version) tool and get some sanding drums (course and medium grit). These puppies make deburring holes in thick aluminum a breeze. After you get done with the dremel, go over the holes with a scotchbrite pad to polish everything.

If I were you, I would try to remove the scratch. Go to the aviation department at Home Depot and pick up some course and medium grit emery cloth. That stuff eats through scratches. Finish it up with some fine emery cloth and the scotchbrite pad.

Good Luck,

[Rick6a]

Originally Posted by RVG8tor

...... .working the lightening holes, with a 1 in scotch bite wheel.....but we did not deal with thick aluminium like the VS doubler.

Mike,

We all tend to develop deburring preferences. My personal choices are based upon years of production work using just about every deburring tool imaginable. A thing that struck me when I decided to build an airplane is finding that many builders tend to overthink the deburring process. The goal is to simply to "break the sharp edges." In practice, a typical production inspector will simply run his fingers lightly over the work to see if you have succeeded.

Like most production workers, I just reach for a common (1/4" or larger) drill bit to debur most rivet holes.

The photo on the left shows a widely available tool that can make short work of deburring lightening holes. Its (replaceable) cutter swivels about the handle. Simply rotate the tool around the edge of the lightening hole a pass or two and you are done. Spare cutters can be stowed inside its handle, but in practice you can go years without changing one. If you are deft, the tool also deburs straight stock fairly well. Another favorite deburring tool in my collection is shown on the right. Simply place its "V" shaped cutter against the edge of the work and draw the tool towards you to quickly debur the edge of aluminum stock up to 1/8" thick. Its built in hood is a good safety feature.

Not including emory cloth, there are (almost) as many deburring tools out there as there are opinions, so consider the examples shown as merely personal examples one builders' favorite choices.

[RVG8tor]

Rick,

So if I understand you correctly, as long as I take the edge off of thick stock AL, line the holes in the VS doubler then I am OK, there is not need to emory, scotch brite wheel the flat surface on the inside of the holes. On the outer edges of this part there are little bumps that look like left over marks from the part cutout process, a simple edge deburr would make the part not have a sharp edge but it would still have a bump, is that OK in your opinion?

Thanks

PS I do have both the tools you pictured in you reply.

[Brantel]

1" scotchbrite wheels mounted in a die grinder are excellent for doing this.

I would get some now and use them. These work great on skins as well and for doing anything that is not practical on the big wheel. They don't last as long as the big wheel and are not really that cheap. You will also need a mandrel for them. I think Avery sells them.



Mandrel

[Rick6a]

Originally Posted by RVG8tor

.... On the outer edges of this part there are little bumps that look like left over marks from the part cutout process, a simple edge deburr would make the part not have a sharp edge but it would still have a bump, is that OK in your opinion?....

Those bumps are raised areas produced by the factory shearing process. You will see many of them over the course of the project. Good practice would have you remove them. Depending upon the size and shape of a particular part....I remove them any number of ways including (but not limited to) a 2" sanding disk fitted to a right angle die grinder, a vixen or other file, or the easiest way when possible, leaning the bump against a 6" medium scotchbrite wheel fitted to one side of my bench grinder.

[RVG8tor]

Awesome guys, just the confirmation and info I needed!

Cheers

[GAHco]

On outer edges I lightly draw file (move the file sideways instead of back and forth) until the bumps are gone. This is done perpendicular to the sheet edge.

Then I break the edges the same way. This is done at an angle to the sheet edge.

I usually do this with an eight inch fine mill file using a light touch.

Then I run maroon scotch brite pad by hand back and forth until it feels smooth and clean.

In inside curves or holes I clean with the appropriate size sanding drum, then i use a scotch brite flapper wheel on a drill or a regulated die grinder.

The old test is run a silk hankie along the edge, if it catches, go back and finish it.

Some may say all this is excessive, but I want something better than the spam can stamped out models.

To the knowledgeable, we don't want to "Fret" and then "Crack"

[mgomez]

Mike,

Forgive me for diverting the thread, but I bet there's a good story here: how is it that you flew both the F-15 (USAF jet) and the F-14 (Navy jet.)

I'd have sent this as a private message, but I bet others would like to know too.

Cheers,
Martin

[johnp]

my legally blind father does most of my deburring/edge finishing. the drill goes like this:

8-12 strokes with coarse emery cloth
8-12 strokes with medium
8-12 strokes with fine
8-12 strokes with scotchbrite pad

knocks off those little "ticks" left by the cutting operation in all but the thickest (.125) material