SonexBuilders.net

Just aquired a Waiex tail kit and have some questions.

Who's got the best dimple die sets for sonex supplied flush rivets? Im confused from the archives regarding issues with the factory dimple dies and certain batches of flush rivets.

C-frame yes or no?

What brand hand riveter and pneumatic riveter do you guys recommend? What about the Zenith modified riveters?

Thanks in advance, Happy New Year!

Anthony Hanson
Ft. Rucker, AL
Owner/pilot N69ZZ, future Waiex Flyer.

Anthony,
Congrats on your tail kit and welcome to the tribe!

I prefer the Avery dimple dies. They don't sell direct anymore but most of the major aviation and homebuilding places carry their stuff. I have a couple Harbor Frieght pneumatic riveters. Just make sure all the parts are screwed on tight now and then. I have an old Sears pop rivet gun from back when they sold quality stuff made in the USA. Also have some Harbor Freight cheapies that I bought to hack up as required. Funny, I have not had to yet. I do have a C frame dimpler, you will need one unless you buy the Sonex type dimple die.

Don't use the Zenith modified riveter, it is made specifically to modify the head of the aluminum rivets they use. We use stainless rivets which do not get modified.

The Sonex dimple dies i got were way too steep an angle and opened the drilled hole too much. Avery dies seemed much better, did not know they were no longer selling direct - Drat. However, very easy to make your own die sets if you have access to any small lathe, even the smallest little table top hobby lathe will work. Use standard 118 degree drill bit to make the seat in the female die, and machine the male die just a tad steeper to about 120 degrees. Works great for me, can pre drill with #32 bit which will just accept a 1/8" Cleco, and hole still good for normal Sonex rivets. Note: the rivets I used were from before Sonex supplier changed design, and heads were less than 120 degrees. Check actual angle of your rivet heads (not just what book says) before proceeding.

As to Zenith, Zenair (Avex ?) rivets: If you try a pair of those to join two parts, you will find that the parts can be moved relative to one another. Do same with 2 Sonex rivets and they will not move. The Zenith type rivets (aluminum rivet, steel mandrel) seem to be designed to form a bulge then pull that tight to parts, while the Sonex rivets expand their shanks to fill the holes, more like solid driven rivets. However, because of that difference, I have found the Zenith type rivets are ideal for riveting anything to fiberglass, much less change of breaking out parts of the fiberglass, and less distortion of whatever is riveted to the fiberglass, such as hinges. Those aluminum rivets are at least as strong as the fiberglass.

Zenith uses flush (countersunk) rivets on flat un-dimpled, un-countersunk materiel and forms the perimeter of the head into a dome when pulled. Result when done right is tight seal around the edge, and a smaller head size than Sonex domed rivets. I tried some Sonex supplied flush SS rivets with the Zenith rivet pulling dies and looked close to right. If were to build another plane, might make some custom dies and play with that a bit more.

David A. Sonex TD, CAMit 3300

Great replies, thanks all.

How does this tool/equipment list look to get my project off to a good start?

Avery POP GRIP DIMPLERS 3/32" and 1/8"
http://www.aircraftspruce.com/catalog/t ... ckkey=6499

AIR HYDRAULIC RIVETER complete with nosepieces (3/32" 1/8", 5/32", and 3/16" rivets)
http://www.aircraftspruce.com/catalog/t ... cfer=13280

Professional Hand Plier Rivet Tool wrench and nosepieces (3/32", 1/8", 5/32", & 3/16")
http://www.aircraftspruce.com/catalog/t ... ecfer=7739

ah

Those tools would be fine but if you want to go less expensive you can get both rivets from harbor freight much cheaper. Look at items 93458 and 38353. I used them both for my whole scratch build sonex project and they held up and worked just as good as the Avery tools versions.

Keith
#554

nosky2high wrote:Great replies, thanks all.

How does this tool/equipment list look to get my project off to a good start?

Welcome, and good luck with your build!

Honestly, I'd save your money and skip the AC Spruce Riveter. As others have said, the cheap pneumatic Harbor Freight rivet puller is fine for the Sonex. I've got almost 500 hours in my build so far, and its going strong! Just needs parts re-tightened every so often, and the jaws sometimes need to be adjusted as the lock-nut slips a little bit over time.

When it comes to the dimpler tools, the Avery units are OK but all "nail" dimplers are a big PITA over the long run. The nails break after ~5-20 pulls if you use air and dial down the pressure to 25-40 PSI (depending on the material and your particular setup). They last a little longer if you use a hand-puller but that'll make for a very sore hand, and they still break eventually.

I gave up doing it that way after the tail kit and bought a somewhat-low-price rivet squeezer (http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=ATSRS-1SD) and some good quality dimple dies (http://www.cleavelandtool.com/120-degree-dies-for-1_8-pop-rivets/productinfo/DIECS4-4/#.VorA-vkrKUk) - be sure to get dimple dies that are designed for pulled rivets! The angle for pulled/pop rivets is different from driven rivets. Those two things will get you started, though you'll still need the nail-style dimplers to deal with big parts and skins. Eventually you can grab a C-Frame to dimple skins and other big parts.

NOTE: You'll need some nail-style dimplers in any case, because the Sonex was not designed with flush rivets in mind. Some holes are impossible to get into with a C-Frame or a rivet squeezer, and the tight spaces will actually require you to grind down some of the nail-style dimple dies so that they can fit up near flanges (like wing & tail ribs).

As a sailplane pilot, I couldn't conscience an aircraft skin covered in round-head rivets... So I ordered my Sonex kit with all-flush rivets. I have to say that if I did it all over again I might change my tune. Its still a tough call, but the flush rivets add about 10% to my labor totals, plus some extra fussing and stress (due to the aforementioned fact that the aircraft was not designed with this in mind. Its not hard, but you do have to fiddle with some things and modify a few steps here and there). Furthermore, there's a risk of damaging or deforming parts whenever you dimple them - I tore a tail skin being over-zealous with the C-Frame and it cost me ~$150 and several weeks to get a replacement skin. I'll surely be happy when the Sonex is finished and sleek; but the longer my project goes on the more I realize the importance of a fast & uncomplicated build. A longer build-time just means that many more opportunities for Life & other distractions to get in the way!

Good luck, take care,

--Noel
Sonex #1339
TD, Center-stick, Acro-aileron, flush pulled-rivets, Aerovee Turbo
Wings & Tail Complete, Fuselage underway [~500 hours so far]
Photo Album of my Build

P.S. If you go ahead with flush rivets, here's the drilling sequence that works best:

• Pilot-Drill with a #40 bit
• Align & clamp parts.
• Drill through second item with #40 bit, cleco'ing as-appropriate
• Up-drill to #32 bit, cleco-ing as-appropriate (note that clecos will be very tight in these holes and may not always clamp hard - wiggling them a bit often helps the parts slide in these tight confines)
• Disassemble
• Debur both sides of all holes
• Dimple. This will slightly enlarge the hole, allowing the rivets to fit.
• Surface-prep as-appropriate.

(If you updrill to #30 and then dimple, the holes will stretch and be a bit big for the rivets. This over-sizing is OK in most cases; but drilling to #32 makes for a really nice fit and strong rivet joints. If you dimple before your debur, you will find it very hard to properly debur both sides of the now-angled holes)

Are you certain that you want to go all flush?

:o

:)

I scratch built with a Harbor Freight rivet gun and the Sonex dimple die. I had a box of appropriately sized nails for the Sonex die, and replaced the nail every 10-15 rivets, before they broke. Can't beat the cost :-) As mentioned, you need to drill the holes slightly undersized so they are the right size after dimpling.

I also built my Sonex with a Harbor Freight pneumatic puller that I found on sale for $29.00 (just checked and it's now $39.99). If you are only dimpling the leading edges of the wing then the simple rivet puller style dimple die will work but will extend the time. I had a c-frame for another project so I did my skins with that and it worked very easily. I also had a hand squeezer that used the same dies and that was perfect for the edges and rib flanges. Since I already owned the C-frame and a rivet gun I used them to rivet my spars. I don't think I would do an entire airframe in flush rivets without those tools. If I was only doing the leading edges I would spend the extra time using the cheap stuff and spend the 300 bucks on fun stuff. Building is therapy so whats an extra couple hours?