skydiverlv
Well Known Member
Do the prepunched holes in the skins need to be deburred? I feel negligible difference after debur. Sure would save a lot of time. What have the swamis been doing?
Van's Air Force
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debur prepunched holes?
- Thread starter skydiverlv
- Start date
MartySantic
Well Known Member
They do not require any debur.
skydiverlv
Well Known Member
Great that will save much time. Thanks.
If they all needed deburred....my next question would have been how did you all convince your wife to debur all those holes?
MartySantic
Well Known Member
The "beauty" of the Van's kit!!! Cannot say enough about their engineering!! Tell the wife she can cut the grass now!!
ErichKeane
Well Known Member
We've been deburring all of the holes, though we usually only have to deburr one side. The 'bottom' side of the deburred holes always have a bit of a ridge. If they are in contact with a rib or spar, they could cause a weak spot.
In addition I'm told that the aluminum is like tempered glass, if you leave a rough edge, it'll be a spot that can induce tearing.
In addition I'm told that the aluminum is like tempered glass, if you leave a rough edge, it'll be a spot that can induce tearing.
MartySantic
Well Known Member
Yes, one of the greatest debates (others include priming, etc.). Deburring the hole also reduces the thickness of the skin where you want the shear strength around the rivet. I followed the guidance per Van's engineering. Do not bother.
Deburring debate
I only de-burred a few rivet holes on my plane. The theory says that a rough edge will develop into a crack. That is true on highly stressed parts like the propeller. But how many planes have crashed because sharp edges were not de-burred? I have never heard of even one. An A&P told me that he used to think that deburring was important until he crawled into the tail of a type-certificated factory-built aircraft and found all edges were sharp. Being a first time builder, I followed advice and deburred all edges. But now I wish that I had not. It took me a lot longer to build the plane. I probably did more harm than good by sanding off the alclad coating. If I build another plane, I would only smooth the edges that could possibly cut me while I do maintenance.
Joe
I only de-burred a few rivet holes on my plane. The theory says that a rough edge will develop into a crack. That is true on highly stressed parts like the propeller. But how many planes have crashed because sharp edges were not de-burred? I have never heard of even one. An A&P told me that he used to think that deburring was important until he crawled into the tail of a type-certificated factory-built aircraft and found all edges were sharp. Being a first time builder, I followed advice and deburred all edges. But now I wish that I had not. It took me a lot longer to build the plane. I probably did more harm than good by sanding off the alclad coating. If I build another plane, I would only smooth the edges that could possibly cut me while I do maintenance.
Joe
Gagarin737
Well Known Member
Answer from Van's
My Question(12th march 2009):
Received the empennage kit last week and about to begin.
The punched rivet holes of the RV12 kit looks quite "clean" already. Deburring with a deburring tool takes away material quite fast.
Just to make sure; do you have to debur both sites of the prepunched holes or maybe just the side of the skin/ribs were the punch came out?
Or is using a 3M pad enough to debur those holes? Or is it just necessary to do both sides to relief the stress of the punch.
Regards, Joeri (Netherlands).
Answer from Van's:
Joeri, using a deburring tool just make one light turn around the hole. That's
all that is needed. Some folks are not doing anything. We think it should be done.
Vans
My Question(12th march 2009):
Received the empennage kit last week and about to begin.
The punched rivet holes of the RV12 kit looks quite "clean" already. Deburring with a deburring tool takes away material quite fast.
Just to make sure; do you have to debur both sites of the prepunched holes or maybe just the side of the skin/ribs were the punch came out?
Or is using a 3M pad enough to debur those holes? Or is it just necessary to do both sides to relief the stress of the punch.
Regards, Joeri (Netherlands).
Answer from Van's:
Joeri, using a deburring tool just make one light turn around the hole. That's
all that is needed. Some folks are not doing anything. We think it should be done.
Vans
Geico266
Well Known Member
IMHO, if you want good paint adhesion around the rivets it is a good idea to run the scotch bright pad over the holes on both sides. When the rivet is installed you cannot "rough up" the area closest to the rivet head. Without a good, clean "rough" surface the paint adhesion in these area may not be as good as it should be long term causing the paint to ship off. During paint prep the entire surface of the plane is scotch brighed to rough up the surface anyway. Cleaning up the holes is certainly not going to hurt.
JMHO
JMHO
Last edited:
Deburing
One other reason for deburing is to allow the skins to sit flush together without any trapped burs between them when they are rivited. If there are burs there is only a small surface area of the burr mating between the skins. This is then a weaker joint. Deburring of the holes was one of the recommendations that came out of the Comet crash in the 1950's. An ex Dehaviland airframe engineer who was at dehaviland at the time of these disasters made sure I deburred all the holes when I was a hanger brat working on Beavers in NZ many years ago.
On RV's it probably does not mater much in the scheme of things. But for highly stressed parts that flex it does.
Rob
p.s. See Robyn if you are reading this I was listening.
One other reason for deburing is to allow the skins to sit flush together without any trapped burs between them when they are rivited. If there are burs there is only a small surface area of the burr mating between the skins. This is then a weaker joint. Deburring of the holes was one of the recommendations that came out of the Comet crash in the 1950's. An ex Dehaviland airframe engineer who was at dehaviland at the time of these disasters made sure I deburred all the holes when I was a hanger brat working on Beavers in NZ many years ago.
On RV's it probably does not mater much in the scheme of things. But for highly stressed parts that flex it does.
Rob
p.s. See Robyn if you are reading this I was listening.
RV8or highlights an important point, a burr and a sharp edge are not the same. A burr looks like a burr, a rough bit of metal like drill shavings that must be removed. A sharp edge isn't necessarily all that sharp, and depends on how sharp the tooling is on the fabricator the day your parts were made. That edge isn't a notch on a highly stressed part, like a prop. You can leave it be.
Which raises the interesting point that all the other kits don't need to have those edges dulled either, though it seems a tradition. They're made on the same tooling. But because you drill the holes final size, you can get burrs. They can typically be brushed off with your fingers.
John Siebold
Which raises the interesting point that all the other kits don't need to have those edges dulled either, though it seems a tradition. They're made on the same tooling. But because you drill the holes final size, you can get burrs. They can typically be brushed off with your fingers.
John Siebold
Deburring
Hey small world I did the same with Beavers & Lodestars with Fieldair in NZ many moons ago Rob...LOL
Hey small world I did the same with Beavers & Lodestars with Fieldair in NZ many moons ago Rob...LOL
rzbill
Well Known Member
Maybe the punching is better now.
If the punching deformation of the aluminum sheet is still that same as my -7 kit, I would not consider ignoring hole preparation... but thats me.
Any sharp edge is a stress concentrator. Burr dingleberry or not. The CNC punching machine that Vans used on my -7 left considerable sharp raised rings around each hole on the die side. Match drilling did not eliminate these rings. Only deburring removed the sharp rings. I actially moved to using a drill bit (135 degree tip angle vs 100 degree deburr tool) because it removed less material to get a smooth surface.
If you are planning on painting, Larrys scotchbrite method will work fine.
Sure, there can be a case made for low stress stuctures not needing deburring. The opposite case can be made for never flying in a homebuilt you didn't build yourself.
If the punching deformation of the aluminum sheet is still that same as my -7 kit, I would not consider ignoring hole preparation... but thats me.
Any sharp edge is a stress concentrator. Burr dingleberry or not. The CNC punching machine that Vans used on my -7 left considerable sharp raised rings around each hole on the die side. Match drilling did not eliminate these rings. Only deburring removed the sharp rings. I actially moved to using a drill bit (135 degree tip angle vs 100 degree deburr tool) because it removed less material to get a smooth surface.
If you are planning on painting, Larrys scotchbrite method will work fine.
Sure, there can be a case made for low stress stuctures not needing deburring. The opposite case can be made for never flying in a homebuilt you didn't build yourself.
RudiGreyling
Well Known Member
My 2cents,
Gents don't get confused...The RV12 is not the same as RV3/4/6/7/8/9/10 it uses pop/blind rivets instead and the holes are full size already. On the solid rivet RV counterparts you drill every hole again to full size, you also assemble with a solid rivet that swells more and put more stress on the hole. Those airplanes are also larger and some aerobatic so even more rivet/hole stresses.
If the recent Vans email is true for the RV12 specifically, then I see Vans has back tracked on the exact same question I asked them comparing my RV7 to RV12 deburing. I guess it depends on who you get on the other side of the line at Vans.
Their answer then to me was on the RV12 full sized prepunched holes it should not be necessary, but run your finger over and feel if you need it or not. Any hole you visit with a drill you HAVE TO debur. Makes sense?
That is exactly what I have done, and ended up with little deburring on the RV12.
Advise is worth what you paid for it, 2 cents
Regards,
Rudi
Gents don't get confused...The RV12 is not the same as RV3/4/6/7/8/9/10 it uses pop/blind rivets instead and the holes are full size already. On the solid rivet RV counterparts you drill every hole again to full size, you also assemble with a solid rivet that swells more and put more stress on the hole. Those airplanes are also larger and some aerobatic so even more rivet/hole stresses.
If the recent Vans email is true for the RV12 specifically, then I see Vans has back tracked on the exact same question I asked them comparing my RV7 to RV12 deburing. I guess it depends on who you get on the other side of the line at Vans.
Their answer then to me was on the RV12 full sized prepunched holes it should not be necessary, but run your finger over and feel if you need it or not. Any hole you visit with a drill you HAVE TO debur. Makes sense?
That is exactly what I have done, and ended up with little deburring on the RV12.
Advise is worth what you paid for it, 2 cents
Regards,
Rudi
Deburring
One other point touched on by Larry where the punch has punched the hole and then the plastic is removed around the immediate vacinity of the hole the plastic glue is pushed hard on the metal and for this reason I scotch brite the sheet ready for painting before I dimple to remove this glue.
Just my 2 pence worth
Cheers
Rob
One other point touched on by Larry where the punch has punched the hole and then the plastic is removed around the immediate vacinity of the hole the plastic glue is pushed hard on the metal and for this reason I scotch brite the sheet ready for painting before I dimple to remove this glue.
Just my 2 pence worth
Cheers
Rob
