Metal Magic: Dimpling and Countersinking

[@JMAv8Tor]

These are great! Keep them coming please!!!

[@KitplanesMagazine]

You got it. We'll have more than 20 episodes total, plus we're working on a couple of bonus features based on feedback from the series.

[@ericspeltier]

Great content! Are countersunk rivets considered watertight? (Not for a submarine, but enough to keep the water out of a plane?)

[@KitplanesMagazine]

Yes.

[@peteporpora1630]

I would like to see an example of using a frame squeezer and a pulled dimple die set. You can't reach the center of a wing skin with your pneumatic squeezer.

[@tdrager]

Thanks for this thorough video. I have a hole stretch issue. I'm building an electric Xenos like yours, with the Zaero kit. I just drilled eight 1/8 holes in two .032 inch 6061T6 stabilator spar to rib attachment structure. The Sonex plans say to dimple and pull a CCC-42 countersunk pop rivet. However, if I dimple the 1/8 inch hole, it will open up too much and the rivet may not set. I failed to downsize the drill a few sizes to account for the hole stretch. Should I either: A) Machine the countersink instead of dimpling? B) Combination of 50% machine countersink and 50% dimpling? C) Upsize to CCC-52 rivet and dimple? D) Install a 1/8 inch stainless steel reinforcement washer behind the rivet? This would ensure the rivet sets properly. This is a common exterior aircraft grade washer used on countersunk fiberglass wing tips. This stock washer would have to be ground to fit properly, but would ensure structural integrity.

[@jeremykemp3782]

useful content thanks

[@kevinpereira7864]

More of these please! Rv-8 on order :)

[@surebrah]

The man has two watches. And thanks for the tips.

[@gordonyork6638]

Double fisted time teller.

[@Max_Janszen]

he knows what time it is and is absolutely sure of it!

[@MRatinoff]

What is the model of pilot watch worn on the left wrist?

[@christiangerv2166]

Very interesting video(s)! I am to put some aluminium parts together on an old car, and would like to use the countersinking method. I have holes drilled with 4,5 mm, so 1) what size rivets should I use and 2) what size drill goes into the cage? Best regards Christian Gervoe

[@stick9648]

Know rivet size before drilling to choose the right "bit" .

[@crooked-halo]

Aircraft structures & sheet metal is my career. Maybe it’s different with home built planes, but he didn’t say a word about not countersinking too deep, where the bit goes all the way through. There needs to be a certain amount of straight metal at the bottom of that countersink! Also, he didn’t talk about knowing if your countersink is set correctly & making a hole of correct depth. The way you tell is by dropping a rivet into the hole on a practice piece of aluminum until the rivet head sits flush. Insufficient information here!

[@GordonNoones]

The more I watch these videos, makes me think never purchase homebuilt airplanes, machinist here

[@patrikj]

Indeed you have to not go too deep. And arguably if your sheets are sitting flush you are too deep, since there's a radius on the bottom of the dimple. But if you just countersink enough to make the rivet sit flush, you're too shallow. The thickness of the skin in the dimple means you need to countersink a tad deeper than a flush rivet. Exactly how deep can apparently be debated...

[@paulk1413]

I wonder what happens if you dimple two long edges, such as cabin top and side, maybe 48 inches long. Will all the holes still align or will there be some cumulative material distortion resulting in hole misalignment?

[@robertbuchwalter2297]

Thank you for these videos…my wife and I work sheet metal on a B-17G and always are looking for best practices…

[@AutodidactEngineer]

The saturation is too much to the point that I thought your Dewalt drill was A ryobi one LMAO 🤣

[@alpinlift]

If I have seen this correctly, the same dimple dy set was used for the upper and lower plates. When I do this, the angles do not match. When dimpling, there is an angle of 110° on the lower side of the upper plate. So you would have to use a dimple tool for the lower sheet that has an angle of 110° degrees on the upper side of the lower sheet. And it was not mentioned that if I have a thicker lower sheet that I want to countersink, the angle of the countersink should be 110°. Here is a link where this is explained in detail.kzbin.info/www/bejne/jXSYc3SmZ92pesU. But perhaps it does not play a decisive role in aluminium and small rivets.Perhaps the dimpletool also has the same angle at the top and bottom of the male and female parts.

[@ericthomas8147]

Did those seem underdimpled to anyone else?

[@alexc30]

I agree - they were a little under-dimpled; I did many tests with drilled and deburred "coupons" of various thicknesses of aluminum sheet, and they required that the dies be far tighter than this video suggests (sorry, Paul). Just having the dies barely touching each other was not sufficient in my hands. Have the dies touch, and then go another full turn on the adjustable set. That made my dimples perfect ... and this is the general method recommended by Mike at Cleaveland Aircraft Tool (where I bought my dies - probably the best dies for homebuilts). The reason I did these tests is that my initial dimples for the empennage kit of my RV-14A were a little "under done" ... and I wanted to determine, empirically, the best way to dimple. If you have a DRDT-2, the same principle works (get the dies snug, and then one full turn).

[@alexc30]

another point of reference - you can also purchase substructure dimple dies for the (e.g.) ribs that dimple just a little deeper, to which the skin dimples fit a little more snug. Again, Cleaveland Aircraft Tool is the source (and no, I don't work for them - they are, in my opinion, the best source for tools to build RVs and other homebuilts). And don't get me started on tank dimple dies ... another dimple die set that worked well for my fuel tanks.

[@jeremykemp3782]

@@alexc30 surely it depends on how thick the sheet metal is to start with