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Do what yer' Momma said...
Go Play!
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Deburring holes to be Dimpled - View Thread
Basic question I know, but what do people do? I am pretty much through my HS and VS. I just bought the Standard Aircraft Handbook and have been having a read. Larry Reithmaier (the author) states quite specifically that you should not debur holes to be dimpled. If this is the case I am happy as I just saved myself a whole lot of work but is this wise? The only thing I can think is it might not be wise if you intend storing the sheets together before you dimple. Also I would probably be inclined to rub some Scotchbrite over the inside edge of the hole after dimpling just to take off any roughness before assembly. Looking through the book it would seem he lists a few reasons for deburing: -Stopping the parts from scratching each other while being worked -Ensuring rivets are set correctly (but only between sandwiched parts. Next to the rivet head is OK? Nowhere does he state that the part is likely to fail in service if you do not debur it. It also seems that the primary reason for relief drilling in corners is to avoid stress fractures while the material is being worked rather than when it is being flown. Am I being extreemly nieve? I know this is one author's opinion but it doesn't seem to gell with what I have heard elsewhere.
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Deburring holes to be Dimpled - RE: - View Thread
I have read that section several times, and I actually re-read it very closely two nights ago. If you look closely at that section, it is really concerned with the amount of metal that is removed during deburring. I'm pretty sure his concern is with enlarging the hole beyond the width of the rivet body. You will notice that when you dimple, the hole actually gets enlarged a bit, so you need to be a little more careful when you deburr a hole that is going to be dimpled. However, using a countersink bit in an electric screwdriver does not usually enlarge the hole, it simply removes the burr on the edge of the hole. I usually do this on all holes. However, the Standard Aircraft Handbook is the bible. If you want to use that as an excuse to not deburr holes to be dimpled, then nobody should be able to question your procedures. There's nothing wrong with following the accepted manual. Just be smart about it. If there is a big burr on the edge of the hole, knock it off, whether you are going to dimple or not. There are several reasons to deburr. First, and probably most important is to smooth rough edges to prevent stress points that could develope into cracks. Not too concerned about this in smaller holes that will be dimpled and riveted, but I debur anyway. Second, is to remove burrs that could get trapped between riveted pieces, which would reduce the strength. I say always check this. Third, is to remove rough edges that could cut your body appendages or scratch another piece of metal. Not too concerned about this in a hole that is going to be riveted.
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Deburring holes to be Dimpled - RE: - View Thread
I wholeheartedly disagree!!! If you dimple a hole that has a burr in it, the burr will deform the dimple when it is formed. You need to at least clean out the drilled hole and a deburring tool seems to be the easiest way. Small nicks and cracks also create stress risers that will crack later on or create small microscopic cracks as the dimple is formed. These cracks may become larger over time. You don't need to spend a lot of time deburring as you are not trying to ream the hole out to a larger size, just smooth it out and make sure the hole is clean for the subsequent steps. Most of the work in building these AL planes is the metal prep. Skipping this step could be disasterous.
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Elevator Stiffeners - 90 degree angle - View Thread
I just finished cutting out my elevators stiffeners and was squeezing the dimples with the dimple dies that I got from Averys. The Avery dimple dies have a nice rounded edge which works nicely with the stiffeners. I noticed that after dimpling the stiffeners the 90 degree angle was pushed out a little, from the edge of the dimple die pushing against the curve in the stiffener. Is this not-so-90-degree angle going to be a problem? Has anyone else noticed this?
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Elevator Stiffeners - 90 degree angle - RE: - View Thread
I ran into the same problem, but then I orderd a small diameter dimple die (only the female) from Avery, so it was possible to dimple without touching the bent-radius. Since then, I used this die more and more in tight corners. But you can also grind one of your dies slightly on one side to give more room to the radius (as the close quarter dies from cleveland)
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| The "cover your butt" section |
This website was built to document my work on my RV-9A in
compliance with the FAA requirements needed to certify my aircraft. My experiences and comments are by
no means to be considered as instructions on how to build an RV-9A or any other aircraft.
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