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11-01-2017, 12:02 PM
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Join Date: Dec 2013
Location: Louisville, KY
Posts: 45
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Misshapen match-drilled holes
While match drilling the W-707 doubler plates for the rear spar I'm accidentally causing the original holes to widen and become misshapen. I'm assuming this is because I'm not holding the drill straight, or I'm moving it around, or I'm applying pressure laterally. I'm not sure.
Anyways, two questions:
1. Is the biggie in this pic useable or am I going to have to order a new rear spar?
2. How do I match drill without doing this? Do I need to get a drill press?
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Guido Bartolucci - Louisville, KY - Bowman Field (KLOU)
RV-8 (N883G): Empennage Finished, Working on Wings
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11-01-2017, 12:42 PM
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Join Date: Mar 2016
Location: Northern VA
Posts: 267
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Can?t comment on drill larger or replace. Would talk to Vans.
Drill press may not work in all situations. Maybe look at a drill bushing?
https://www.browntool.com/Listview/t...a/Default.aspx.
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Brian Lester
Dues Paid - 2020
RV10 Slow Build - #41778
Finish Kit - in progress
RV10builder.com
KVKX / KHEF
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11-01-2017, 12:57 PM
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Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,218
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Dull bits sometimes wander and create odd shaped holes like that. Try a new bit.
Van's is a sane resource on quality control. My guess is they will tell you you're OK, but you should call and verify.
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Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
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11-01-2017, 03:06 PM
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Join Date: Jan 2007
Location: Battleground
Posts: 4,348
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Measure the hole and compare to the mil specs on Vans web site or AC43-1b. You are allowed certain tolerances for a given hole diameter. If it is within tolerance, and you have edge distance, you are probably ok.....
Now, saying that, Vans is the only one who can approve deviations when it is a spar. However, I would rather call them with that information so they know than just sending a picture. It will also educate you.
Make sure you clear your chips on the bit. Sometimes a small chip gets stuck in the flute.
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Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
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11-01-2017, 04:23 PM
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Join Date: Oct 2005
Location: Estes Park, CO
Posts: 3,947
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Pilot
This trick works for most holes and match drilling.
Credit goes to my Mentor, Dave Paule.
Go to the local hardware or hobby store. Look for brass tubing in 12" lengths. Buy one each of each size.
Cut a piece of each starting with the smallest working to largest with each a tiny bit longer.
The smallest one should fit the #41 bit with 1/2" or so of bit sticking out when chucked.
Now you can center a bit without touching the parent hole by selecting the correct tube combinations. Try to drill the pilot hole with the smallest bit you can.
Here's the Kitplanes article.
https://drive.google.com/open?id=0B7...01tUXdGOWdEUlE
Lots more on my Blog (see signature)
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Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/03/2019, plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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11-01-2017, 04:39 PM
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Join Date: Feb 2010
Location: Gardnerville Nv.
Posts: 2,828
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By looking at the drill shavings and the hole it looks like the drill bit is no good, time for a new one, they are cheap compered to parts.
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7A Slider, EFII Angle 360, CS, SJ.
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11-01-2017, 04:48 PM
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Join Date: Jan 2016
Location: Southwest
Posts: 1,119
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reamers
I try and use a #30 and #40 reamer, as appropriate for rivet size, as opposed to a drill bit. Much better hole and this shouldn't happen.
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John S
WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.
Dues paid 2020, worth every penny
RV9A- Status:
Tail 98% done
Wings 98% done
Fuselage Kit 98% done
Finishing Kit 35% canopy done for now
Electrical 5% in work
Firewall Forward 5% in work
www.pilotjohnsrv9.blogspot.com
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11-01-2017, 04:54 PM
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Join Date: Sep 2007
Location: Central IL
Posts: 5,516
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Quote:
Originally Posted by bret
By looking at the drill shavings and the hole it looks like the drill bit is no good, time for a new one, they are cheap compered to parts.
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+1 looks like a melted hole. I got Pan American cobalt bits (Avery - Cleaveland) and have been very happy with life.
__________________
Bill
RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
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11-01-2017, 08:20 PM
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Join Date: Jun 2006
Location: Castaic, CA
Posts: 549
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Are you using a high speed air drill? I find they want to chatter as they start. No need to spin the bit fast, I prefer to use a slow turning cordless electric drill.
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Mike Sumner
Castaic, Ca
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11-01-2017, 08:28 PM
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Join Date: Jun 2012
Location: Frederick, MD
Posts: 821
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Quote:
Originally Posted by bret
By looking at the drill shavings and the hole it looks like the drill bit is no good, time for a new one, they are cheap compered to parts.
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+1 on replacing the bit. A lot of folks don?t realize that if you drop a bit on the floor (concrete) and it hits on the point, it is likely trash. I have watched people put their drill down with the bit hitting the floor. Same result. Colbolt drills fair a little better but still not good.
__________________
Dan Morris
Frederick, MD
PA28-140
Hph 304CZ
RV6 built and sold
N199EC RV6A flying
Learn the facts. "Democracy dies in darkness"
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