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01-26-2017, 12:47 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by 60av8tor
I can't imagine even being able to dimple without drilling. Of the thousands of holes that I drilled, deburred, and dimpled, I always knew when I missed one, because my male dimple die would not go in the hole without a considerable (uncomfortable) amount of force. Would imagine that force/stretch isn't doing much good for the hole...
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Quote:
Originally Posted by gfb
Wally was talking about this at OSH last year and I asked him about it during audience questions and he insisted Vans told him it was approved. I walked down to the Vans tent after and was told it is NOT approved and NOT to do it unless I planned to inspect every single dimple for cracks with a loupe.
The problem is not the holes lining up, it is cracks getting created in each dimple from the stress. I was under the impression that this was no longer an issue with the RV12/14 but it sounds like it's still not true?
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The issue of driving a dimple die pilot through the under sized hole is the concern.
Fatigue tests have been done to confirm that the surface finish on the interior edge of the holes is not a concern (that is why dimple countersinking without final drilling is approved on the RV-12 and 14... their holes are punched to a larger size).
Stretching an un-final drilled hole with a dimple die pilot is a concern and not recommended or endorsed by Van's
Apologizes for the extreme thread drift Bob......
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Last edited by rvbuilder2002 : 01-26-2017 at 12:57 PM.
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01-26-2017, 02:32 PM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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Well, now you've got me wondering too because the RV-12 instructions only sporadically mention match drilling. But I match drill everything anyway, and then deburr everything whether it mentions it or not.
The hardest thing for me to get over is the riveting of skins when I pull a pop rivet and then have this "OH, NO! I forgot to dimple" moment. That happens a lot.
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01-26-2017, 02:35 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by LettersFromFlyoverCountry
Well, now you've got me wondering too because the RV-12 instructions only sporadically mention match drilling. But I match drill everything anyway, and then deburr everything whether it mentions it or not.
The hardest thing for me to get over is the riveting of skins when I pull a pop rivet and then have this "OH, NO! I forgot to dimple" moment. That happens a lot.
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Match drilling on the RV-12 is only required in a few limited circumstances.
The same with final drilling, and that is primarily only on larger diameter screw holes that get large dimples formed in them.
BTW.... per the details in Section 5 of the manual, Match Drilling is when you are using the hole in one part as a pilot/locator hole to drill a hole in another part that does not yet exist.
Final Drilling is enlarging an already existing hole (as in pre-punched holes) to a desired final size.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Last edited by rvbuilder2002 : 01-26-2017 at 02:38 PM.
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01-26-2017, 04:01 PM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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Quote:
Originally Posted by rvbuilder2002
Match drilling on the RV-12 is only required in a few limited circumstances.
The same with final drilling, and that is primarily only on larger diameter screw holes that get large dimples formed in them.
BTW.... per the details in Section 5 of the manual, Match Drilling is when you are using the hole in one part as a pilot/locator hole to drill a hole in another part that does not yet exist.
Final Drilling is enlarging an already existing hole (as in pre-punched holes) to a desired final size.
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I misused the term. I meant "final drilling", not "match drilling."
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01-27-2017, 08:09 AM
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Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
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Quote:
Originally Posted by rvbuilder2002
The same with final drilling, and that is primarily only on larger diameter screw holes that get large dimples formed in them.
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Just working on the rudder skin last night, there's no way I'd rivet the skin without final drilling the holes. I don't recall seeing a note to final drill the holes but maybe it was there.
Anyway, I'm choosing to final drill and deburr everything and every hole.
You can't take the 7A out of the boy.
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01-27-2017, 10:30 AM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by LettersFromFlyoverCountry
Just working on the rudder skin last night, there's no way I'd rivet the skin without final drilling the holes. I don't recall seeing a note to final drill the holes but maybe it was there.
Anyway, I'm choosing to final drill and deburr everything and every hole.
You can't take the 7A out of the boy.
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Totally up to you but it is not required on the RV-12 (though some times it is necessary).
Keep in mind that if you automatically final drill all holes, you may actually be enlarging some holes that are already might be final size.
Say you haven't flutted a rib as well as it could have been which is causing some holes to be mis-aligned..... and you instead final drill to "improve" hole alignment. The holes may have been already final size but they are now slightly oval.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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01-27-2017, 11:13 AM
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Join Date: Aug 2013
Location: Lucerne,Ca
Posts: 272
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Reaming holes
Rather than drilling the under sized holes I would ream them then cleco then ream the next ones. Only needed to ream about 5% of the total holes
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01-27-2017, 01:26 PM
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Join Date: Apr 2010
Location: Tucson, AZ
Posts: 461
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Quote:
Originally Posted by redbaron
Rather than drilling the under sized holes I would ream them then cleco then ream the next ones. Only needed to ream about 5% of the total holes
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I actually built a 12 and am thinking about building a 7 next, so just the opposite way of what has started this thread.
The way for me to put the skins on and other larger structures was to first deburr the side where the punch excited as the holes had sharp edges there. Then cleco the part on and if he pop rivet would go into the hole by hand, fine. If not, I ran a #30 drill bit through the hole manually turning the chuck of the drill to just ream it to size. Insert rivet, pull, done.
Most rivets went in without any further treatment. After 3 years of flying, no cracks and nothing has fallen off yet.
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01-31-2017, 05:04 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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It turns out I may have jumped the gun in my earlier post regarding the dimpling topic? my apologies.
Yesterday it came to my attention that in 2009, Van?s Engineering staff released a specific approval (*with qualifications) to Synergy Air regarding dimpling without final drilling.
*Note that the approval calls for use of special dimple dies with pilots that slip fit into the smaller prepunched holes to avoid unnecessarily stretching the hole while dimpling. (Van?s does not have information on a specific source for these dies.)
With permission from Van?s, I?ve provided a link to the approval below:
Link to Dimple.pdf
Van?s covers the topic of dimpling in Section 5 of the builders manuals and recommends that builders read and follow the recommendations there.
Link to Section 5
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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02-01-2017, 05:13 AM
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Join Date: Feb 2015
Location: Locust Grove, GA
Posts: 621
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Thanks for following up!
Quote:
Originally Posted by rvbuilder2002
It turns out I may have jumped the gun in my earlier post regarding the dimpling topic? my apologies.
Yesterday it came to my attention that in 2009, Van?s Engineering staff released a specific approval (*with qualifications) to Synergy Air regarding dimpling without final drilling.
*Note that the approval calls for use of special dimple dies with pilots that slip fit into the smaller prepunched holes to avoid unnecessarily stretching the hole while dimpling. (Van?s does not have information on a specific source for these dies.)
With permission from Van?s, I?ve provided a link to the approval below:
Link to Dimple.pdf
Van?s covers the topic of dimpling in Section 5 of the builders manuals and recommends that builders read and follow the recommendations there.
Link to Section 5
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It's certainly comforting to know that the method I was taught at Synergy was indeed approved and acceptable. It was difficult to believe that they were doing something unapproved, as they are (in my opinion) the best Builder Assist shop out there for RV's.
Kudos to you Scott, for taking the time to dig a little deeper and research this with Van's. A huge thank you for letting all of us know that the direct to dimple die method had been tested by Van's and was approved under controlled conditions!
__________________
Krea Ellis
Locust Grove, GA
DA20-A1 "Princess Amelia" - gone home to Amelia Island
RV-7A Phase 2
RV-10 under construction at Synergy Air South
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