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dwranda

Well Known Member
I'm practicing before I put actual airplane parts at risk and can't figure out how much deburring is OK. This pic shows a ridge around a hole. I have a deburring tool but it doesn't seem to take the ridge off without extreme pressure and many revolutions. I even put the deburring head in my cordless drill and it still doesn't want to touch the ridge. I have also used an oversize drill bit and that seems to work better but countersinks the hole slightly. Is that OK?
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Here is my practice creation. I also learned turning the pressure down on the gun helps immensely. I was running at about 60 psi and turned it down to 30 and had much better results.
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Thanks!!!
 
My guess is that the practice hole in your first photo was made in some scrap aluminum of unknown material type?
It is typical of a hole drilled in very soft aluminum, but not typical of what you will get most of the time in aircraft aluminum. In soft material it does make a rather pronounced bur on the punch through side which is difficult to remove without countersinking a bit like you described.

Holes drilled in in 2024-T3 aluminum will not have a bur that is so pronounced, and it will remove much easier. Holes in 6061-T6 (which is softer) are somewhat like your example but still usually not as bad.

Is your deburring tool cutter new? The performance difference between a used and a new cutter is substantial. Particularly on softer material.
 
On your final pieces you definitely don't want larger burrs as they can be stress risers, make the pieces not sit flat, and cause issues with the dimple. As rvbuilder said, this may be material or it may be the tool. If you plan on priming that area you can also attempt to scotch-brite the burr off.

Which deburring tool are you using? I have had good success with both the avery and Cleaveland ones.
 
I use drill bits (quite a bit larger than hole) to take out larger burrs like that. Just spin them with your fingers and it should take it off quickly.

Larry
 
I'm using the speed driver "dog leg" deburring tool. It was ordered brand new from Brown tool. The part in question is a wing rib. I guess the ridge must be caused by my drilling through the pre punched hole. I discovered some not so sharp drill bits in my inventory so do you think maybe that could be causing such a big ridge?
 
Dull bits

dwranda said:
I'm using the speed driver "dog leg" deburring tool. It was ordered brand new from Brown tool. The part in question is a wing rib. I guess the ridge must be caused by my drilling through the pre punched hole. I discovered some not so sharp drill bits in my inventory so do you think maybe that could be causing such a big ridge?
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Yep.
Buy some reamers. Almost no burr and perfectly round holes.
 
What the man with the hat said: Get some reamers.

Call me Mr. Particular, but when I make new holes (eg. leading edge joint plate etc.), I drill them with either #41 and #31 and use the #40 and #30 reamer as well, resulting in less need for aggressive deburring.
 
Put the deburring bit in a cordless screwdriver/drill and put the setting on low. it works very well for me, i allow it to spin 1-2 revolutions.
 
Mr Particular

nilberg said:
What the man with the hat said: Get some reamers.

Call me Mr. Particular, but when I make new holes (eg. leading edge joint plate etc.), I drill them with either #41 and #31 and use the #40 and #30 reamer as well, resulting in less need for aggressive deburring.
Click to expand...

Make that two Mr Particulars. I do the same.
 
Dave, smart move to practice on scrap. I made a fair amount of scrap during my build...... I found that lightly twirlling a sharp drill bit worked well for deburring. And I also used reamers extensively.

Andy
 
If reamers float your boat, go for it. But a really good scifi & computer tech writer is fond of saying, 'Better is the enemy of good enough.' I doubt you could have found many #40 reamers at Cessna or Piper when they built all those trainers 50 years ago (that are still flying).

Dull bits will cause the rolled up edges, as others have said. Aluminum stuck to the cutting edge of a bit will do that too (usually caused by a dull bit...). My experience was like yours; a 100 degree deburring tool usually misses the burr, unless you cut a significant taper into the hole (a not so good thing). Others mentioned using a drill bit as a deburring tool; most drill bits have 135 degree points. This is closer to being parallel to the surface of the sheet, allowing you to cut away the burr without getting too deep in the hole. I wish we could buy something closer to 150-160 degrees.

Charlie
 
A three flute hand deburring tool works well ... even on the stainless firewall. Two revolutions with firm pressure (nothing extreme) works well for me.

30 psi is about right with a 2x or 3x gun with a straight set for round head rivets (470's) or flush heads (426's). If is has a bend, expect more pressure in the line.

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Avery closed up shop (bummer for us!) but I'm sure you can get similar tools from other vendors.
 
I never found the speed - dogleg - tool to work very well

I use one of these instead

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Also, with holes in thin material, a scotchbright pad works well too
 
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