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Page 07-07 question

mulde35d

Well Known Member
Friend
Steps 3 and 4 advise to only final drill the trailing edge, tip rib, and counterbalance rib where the flanges meet the skins. I would assume the rest of the holes are the newer RV-14 only parts that don't require final drilling (spar and stiffeners).

With that being said step 6 states debur all holes and edges that have not been deburred. Does it mean all holes that you Final / Match drilled in step 3 and 4 or "all holes"?

I only ask because it is a big difference in the amount of work. Thanks
 
Deburring is one of the most time-consuming tasks of building.

Section 5.2 advises the following...

"All aluminum edges and corners must be smoothed and radiused to prevent this stress concentration from occurring."

and

"All drilled holes, or prepunched holes that have been final-drilled to a larger size, should also be deburred. Holes that were factory punched to final size can be inspected and only deburred if needed (with the exception of large holes to be dimpled for screws - see below)."

It's worth noting the caution also...

"Many novice builders deburr excessively deep. Deburring should not produce a significant chamfer/countersink on the edge of the hole. Be particularly careful deburring holes in .020 or thinner sheet. By the time both sides have been deburred the hole could be enlarged."

Speaking only for myself, I deburred all holes and all edges. As I look back on my time tracking spreadsheet, to give you an idea of how long that can take, I see I spent 4 hours and 39 minutes deburring just the top and bottom wing skins. I recall my hands feeling rather raw. To reduce the potential for RMI (repetitive motion injury), I obtained this to manage deburring.

61RKFVFd%2BvL._SL600_.jpg


You can use the power screwdriver with a deburring bit in conjunction with this adapter.

429.jpg
 
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I deburr on condition. That is, I run my fingernail over the hole and if it catches the edge it needs to be deburred. Those rudder skins are 0.016 in. so a very light touch is required.
 
Deburring is one of those topics - when it comes to pre-punched holes - that generates about as much controversy as primers. My own conclusions/observations after reading as much as I can find on these topics and deburring/building for two years is the following:

1. For thinner skins/parts, where holes are pre-punched fully to size (where instructions don't include any "final" or "match" drilling) deburring is generally needed only where there is a burr you can feel as previously mentioned. Deburring on thin skins has it's own risks - mainly chamfering the edge to a point where dimpling might over stretch it and increase risk of crack rather than decrease it. It's very easy to over-deburr thin skins/parts.

2. Van's and Synergy Air usually go straight to dimpling holes where rule #1 applies. Synergy does this with blue vinyl still in place.

3. I have found that if I scuff skins/parts that I intend to prime with ScotchBrite pads this removes burrs better than a deburring tool and has essentially zero risk of too much thinning of thin skins.

4. On thicker parts I usually deburr at least the "exit" side of the punch which is quite evident on inspection, and other holes (those pre-drilled fully to size) on condition.

Just my PERSONAL policy and process - your mileage may vary!
 
Much appreciated. I am also seeing good success with the scotchbrite pad doing the deburring work on the holes. Now if I could just find a cloth that was actually lint free for drying parts before priming then all my problems would be solved. (p.s. the ones that claim to be lint free haven't been so far)
 
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