danielhv

danielhv

Well Known Member
Ok, maybe Im doing this wrong... I have tried 2 different bits, with no luck. Or maybe I AM doing it right and I'm just being too picky. If I use a 3 flute bit, it leaves pretty bad chatter marks, no matter how soft or hard I push... or how slow or fast I spin. So I got a 6 flute bit, which is MUCH smoother, but I have to CS more material to get all the burrs off... and even then, some are not 100% gone. Now when I say burr, I am under the impression that pieces of metal hanging off the edge of the hole is a burr. Now, another issue that adds to this one... :rolleyes: My drill stop seems to be dragging the chips from drilling forming a circle around the hole. Not deep or anything, but you can feel some of them. I've tried blowing them while drilling but no change. The drill stop feels smooth on the side that hits the skin, so I dunno. Here is my question... after deburring the tank skins last night, it felt OK. Not as good as I want, but not bad either. I scrubbed the mating surfaces down with a scotchbrite pad, and BAM! They were as smooth as can be... So, am I wasting my time spinning these debur bits? Should I eliminate them all together and just scotchbrite all mating surfaces/holes after drilling which seems to yield better results all around?

I really feel like Im getting more and more picky as this build goes on.
 
Geico266 said:
Go with the Scotch Bright, easy on the alcad.
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good god that would save me alot of time... I prime the inside skins with self etch rattle can. I'll try it out and see is I can get good results while being easy on the alcad. :)
 
danielhv said:
good god that would save me alot of time... I prime the inside skins with self etch rattle can. I'll try it out and see is I can get good results while being easy on the alcad. :)
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You mentioned on a previous post you are deburring your fuel tank. I hope when you say you are priming the "inside skins" you are not referring to the fuel tanks. It would not be good at all to prime the inside of those tanks.

I am sure I misunderstood your post but thought I might post just for clarification.
 
RVbySDI said:
You mentioned on a previous post you are deburring your fuel tank. I hope when you say you are priming the "inside skins" you are not referring to the fuel tanks. It would not be good at all to prime the inside of those tanks.

I am sure I misunderstood your post but thought I might post just for clarification.
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Oh no... I wasn't supposed to prime those? KIDDING!! :D Nah, I know better. Just priming all the other skin insides...
 
Whoa, count me in.

Is it really acceptable practice to simply knock the burrs off with some scotchbright? de-burring with the little... whatever it's called (blue handle, counter-sink-looking-bit) takes forever. Sometimes I de-burr with the de-burring tool and don't like the results too much, so I hit it with the scotchbright and it's much better.

This would be a major time saver. Mel - I'm guessing you're biding your time before you comment...?

MB
 
Previously I used the 3 flute tool and it also left chatter marks. I eventually changed to the 6 flute CS and it works much better.

I spin it with my fingers and apply very gently pressure. With 6 flutes, it doesn't take much spinning to remove the material.

It does countersink the edges just a bit, but I'm more comfortable with it's results than I am with a chattering bit.

Several people use an oversize drill bit and they chatter (and CS) the hole too. When I've compared my 6 flute results with others drill bit methods, my holes aren't any deeper than theirs but mine are chatter free. So I'll stick with the 6-flute method.
 
Phil said:
Previously I used the 3 flute tool and it also left chatter marks. I eventually changed to the 6 flute CS and it works much better.

I spin it with my fingers and apply very gently pressure. With 6 flutes, it doesn't take much spinning to remove the material.

It does countersink the edges just a bit, but I'm more comfortable with it's results than I am with a chattering bit.

Several people use an oversize drill bit and they chatter (and CS) the hole too. When I've compared my 6 flute results with others drill bit methods, my holes aren't any deeper than theirs but mine are chatter free. So I'll stick with the 6-flute method.
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I have a 6-flute as well... but am the opposite of you... I DO NOT like the results... It takes more pressure to get the burrs off, and countersinks too much IMO. It still leaves a burr on the edge of the hole (not inside) that are caused by the drill stop touching the skin. While the material removed does have 100% LESS chatter marks than that left with my 3-flute, Im just not happy with it. Here is the bit I'm using from Avery Tools:

767.jpg


That being said... I am very interested in hearing more opinions on using scotchbrite pads for deburring (BEFORE dimpling of course). The inside skins and ribs are all going to be primed with the rattle can duplicolor which I am having great results with, so the loss of the alcad should be no factor that I can see (I do NOT live on a coast, and although the rattle can is not solvent resistant, it does provide a good strong layer of protection in absence of the alcad), and the outside skins are all going to be scuffed and painted some day anyways... The results I had after scotchbriting the inside rivet lines of the tank skins were superb. Smooth, no burrs, no cuts, no nothing. Perfect. Im just curious if its acceptable for the rest of the plane.
 
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What are you driving the deburring bit with? I use a 3.6V electric screw driver that is easy to handle and turns very slowly. Avery sell a hex adapter that mates with the 1/4" bit thread. Anything else turns too fast.
Jim Sharkey
 
One thing I found that helped was to keep your drill bits sharp when making your holes and let the bit do the work. It seems that we may push a bit :)too hard when dull and this curls the little barbs back instead of cutting them off. The scotchbrite pad works well, that's something I read that Zenith tells it's builders to do, but it takes a lot of passes if there are hefty burrs. I find that using the blue spin handle from Avery along with their three flute deburr bit always worked well, just a quick turn and the barbs came right off UNLESS the burr was bad, bad burrs seemed to be caused by a dull bit and pushing it through the hole.
 
jsharkey said:
What are you driving the deburring bit with? I use a 3.6V electric screw driver that is easy to handle and turns very slowly. Avery sell a hex adapter that mates with the 1/4" bit thread. Anything else turns too fast.
Jim Sharkey
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I was using this:

73.jpg


Then I bought the hex adapter and tried it in my cordless drill, and with the air drill turned down to ~12psi. Changing speeds or pressing harder/softer has yet to yield acceptable results. (compared to scotchbriting)
 
Boelube on your bits,

Boelube on your countersink cutter,

Boelube on your debur device,

Boelube on your sandwich,
 
Standard Aircraft Handbook

From the Sandard Aircraft Handbook (6th edition) page 87:
"Deburring shall not be performed on predrilled holes that are to be subsequently form countersunk"
Form countersunk is defined as "dimpling" (page 88)
 
I can understand the reluctance to go on record disposing of the old de-burring tool, but there's not a clear answer yet as to whether or not it's okay to go straight to scotchbright pad, assuming you're priming the insides and painting the outsides (eeh, now that I think about it, I may still debur the outsides normally, cuz it's going to take a while to get the thing painted).

As mentioned, when the burrs are bad (i.e. you pushed to hard) the de-burring tool is still going to be required, of course, but in other instances, is it okay to scotchbright in lieu of the de-burring tool?
 
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I use this from Cleaveland Tools

http://www.cleavelandtoolstore.com/prodinfo.asp?number=DB04

It's a single flute carbide bit brazed to a 3" length of hex rod. Spin it in your cordless screwdriver or your fingers. $17.00

I stacked 3 round scotchbrite pads on an arbor chucked in a cordless drill to scuff/deburr large areas like wing skins prior to priming.

Steve
 
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As someone else said, very light pressure. About 1.5 turns does the job 90% of the time, a second try on the remaining 10% gives 90% results again, leaving only about 1% of the holes that are a problem. ON these, I tilt the bit outward, again with very light pressure.

The object is to remove the lip from the hole without countersinking the hole at all.

I prefer a single flute bit, but those are hard to find now. Avery used to carry them. # flute works almost as well; haven't tried a 6 flute.
 
Deburring

I used piloted reamers to open up all the pre-punched holes. They turn out very round that way and don't leave much of a burr. My deburring bit is the 'zero flute' kind. No flutes, just a round hole cut into the cutting surface. It doesn't chatter at all. It is on a hex shaft and mounts in a small battery powered screw driver. Just lightly touch it and give it a quick slow burst.
 
Keep it simple. General purpose De-Burring

This may seem too simple, but the job is just that, and done right you will not damage anything.

Unless you use a NASTY drill bit and force it through the aluminum all it takes is about 1 ounce or less of pressure and a little spin of any de-burr bit (not a countersinking bit) they do look similar but they are not.

I use an old brass turnbuckle barrel that has 1/4-28 thread and a three flute de-burr bit. Very inexpensive and performs excellent results.:)

1) Put the point of the bit in the hole
2) Barely press the non but end with a finger (take your pick)
3) Spin forward lightly and then even backward lightly if you want.
4) Move to next hole and repeat.

The total trick is the very lightly part, your goal is to just de-burr and nothing else.

I scotchbrite after dimpling, but only if I am going to prime or can not operate the de-burr tool in a cramped location.
 
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