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  #1  
Old 09-29-2018, 09:53 AM
Ender Ender is offline
 
Join Date: Dec 2017
Location: Marion, IA
Posts: 21
Default Another deburring question, but hopefully new info

So there is TONS of info on this forum for the process that most people follow for deburring. Most of the questions by the new guys (like me) end up being answered with what "process" people use.

My question is specific to the details you are looking for to know when the piece is done.

I'll give you a quick idea of my process to aid in understanding what I'm seeing. (I know I said I don't want to talk process, this is just to help understand where I get too because most of the stuff below is what people use).
1) Vixen to knock down rough cut marks (sometimes 1inch sander with 120g)

2) B file, usually drawn to clean up vixen and edges/burrs (i don't like edge tool, it just ends up chattering and causes more things to clean up). Sometimes 240g emory (from avery) for burrs/rounding edge "corner" (edge of the edge?).

3) Cut/Polish wheel (1, 2, or 6 inch depending on access) (edge and corners of edge)

For "flossing the teeth", usually 240 then finished with 400

Assume the piece get's to a point where it feels smooth, and your nail does not catch anywhere. At this point, when I inspect the piece there is still small little lines/cuts/marks on the edges. This could be from the B file leaving a mark, the sandpaper leaving a line, or even it's just the deepest line from the original cut marks.

Basically a mark (usually perpendicular to the edge) that was deep enough that the scotchwheel or 400 didn't get down to it.

I usually fix these by hitting it again with the scotchbright or some 400. The 240 or Bfile just seems to add more lines. But it's this last step that really adds time.

I'm not worried about stress risers because the burr on the edges is fine and smooth.

I'm not worried about getting cut or anything later on, because the piece is smooth to the touch.

I am worried that every single one of these tiny little marks could potentially be a crack point. Basically, in my mind, if I can see it, it could cause it. I'm only happy when its perfectly clean (which is difficult to produce)

THIS is the crux of my question (and my OCD probably). I feel like everyone here has seen what I've seen.

I am interested in 1) do you clean them up? and 2) do you think they need to be cleaned up? (I ask it like this because, I assume, many people here go above and beyond and it's tough to tell when their suggestions are necessary for a good safe build, or necessary to be a grand champion --- most people don't delineate when giving their advice)

Thanks in advance for taking the time to answer yet another deburring question!
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  #2  
Old 09-29-2018, 12:32 PM
rocketman1988 rocketman1988 is offline
 
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Location: Sunman, IN
Posts: 1,143
Default Well...

Just a question...

How much deburring was done on the thousands of spam cans out there flying 50+ years after they were built...just saying...
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  #3  
Old 09-29-2018, 02:31 PM
Ender Ender is offline
 
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Location: Marion, IA
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Default

Yeah I've read that, basically nothing right?
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  #4  
Old 09-29-2018, 07:31 PM
Mudfly Mudfly is offline
 
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Location: Alpharetta, Ga
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Default

Initially, I hated the debur part of the build process. I've actually "trained" myself to enjoy it. It's kind of relaxing actually...keep repeating that over and and over. I've listened to several books on tape and currently have a learn to speak Spanish book from audible I'm listening to. With that said, I hope I'm not fluent in Spanish before my project is complete.
Deburring is what it is. You'll find the "happy place" that works for you as your project progresses.
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  #5  
Old 09-29-2018, 07:59 PM
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wirejock wirejock is offline
 
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Default Spanish

Quote:
Originally Posted by Mudfly View Post
Initially, I hated the debur part of the build process. I've actually "trained" myself to enjoy it. It's kind of relaxing actually...keep repeating that over and and over. I've listened to several books on tape and currently have a learn to speak Spanish book from audible I'm listening to. With that said, I hope I'm not fluent in Spanish before my project is complete.
Deburring is what it is. You'll find the "happy place" that works for you as your project progresses.
Eso es in buen idea!
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  #6  
Old 09-29-2018, 08:09 PM
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Sam Buchanan Sam Buchanan is offline
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Location: North Alabama
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Default

Quote:
Originally Posted by Ender View Post
So there is TONS of info on this forum for the process that most people follow for deburring. Most of the questions by the new guys (like me) end up being answered with what "process" people use.
<huge snip>
Whew....I got tired just reading that......

I make one pass down the edge with the 2" ScotchBrite wheel and call it good. I've had no stress cracks on my RV-6 during the past 19 years of flight.
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  #7  
Old 09-30-2018, 12:10 AM
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jcarne jcarne is offline
 
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Location: Worland, Wyoming
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I get my edges pretty dang smooth. Approach depends on the part but I always hit it with a soft scotchbrite wheel as a final step. Most of the time I'm using 400 grit sandcloth. In a nutshell, I'm anal about deburring; I also REALLY wish that I wasn't...

I was also like Shawn, I personally despised deburring in the beginning (wing ribs still haunt me ) but now I kinda like it, just trained my mind to accept it I guess.
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  #8  
Old 09-30-2018, 12:45 AM
Robin8er Robin8er is offline
 
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Location: Oahu HI
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I think the plans say when you can run your finger across it without fear of being cut, its good. Just do that and round your corners and you should be fine. Thats what I do. My plane isnt flying yet though, so my opinion isnt weighted much.
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  #9  
Old 09-30-2018, 01:21 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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I use a similar process but without the Scotchbrite.

I try to arrange things so that all - and I do mean all - of my tool-work is parallel to the edge, even in the slots and narrow places. I have a variety of small files that I can use and for some of them, especially the small round files, rather than move the tool axially (that is, along the tool axis), I rotate it. Note that the rotation direction is towards the cutting direction of the teeth, so that it cuts.

For QC, I look for visual smoothness on all edges. In some areas if there's a question, I'll use a 3-power glass. Occasionally I'll break out my 10 power loup but that's not often. Since I normally use +1.00 reading glasses for this sort of work, I might use my +4.00 power ones for a low-power close-up look before the magnifiers. I regard it as more important that any tooling marks are parallel to the edge than that the edge is perfectly smooth; after all, under enough magnification, it won't be smooth. But a good visual inspection is adequate, and a 10 power magnifier almost always exceeds expectations.

Gotta say, though, that a smooth pretty edge under 10x is beautiful.

Places that are more likely to crack are inside edges, like in between flanges, or the periphery of holes or edges near the holes. If you can imagine how the part might be loaded, cracks are more likely in areas with tension or bending or even shear (or torsion) than with compression. Long constant-section edges are less likely to crack. But this is all relative; a highly-stressed area will always be subject to faster cracking than something that's not loaded.

Yes, holes are important. Cracks can start at fastener holes and in fact, that's not an uncommon crack-initiation location. If a crack is going to start at all, that is.

If a part has bending, the "outer-fiber" has the most load. Areas towards the middle carry less load.

Just to give you some perspective into my project, see my VAF build log about my RV-3B project.

Dave

Last edited by David Paule : 09-30-2018 at 01:23 PM.
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