Back To dimples again!!!

[xblueh2o]

A couple short videos from Cleaveland about proper dimpling and the dies.

[Reflex]

I dimpled for the first time on an RV10 Vertical Stabilizer skin over the last weekend. I have both DRDT-2 and C Frame. I made a test sheet with about 8 holes lined up side by side.

I found that too little, or too much preload, either way, would make a concave area in the sheet around the dimple. I found it was most satisfactory, for my setup, for a 1/3 turn preload (I have read anywhere from 1/4 to 1/2 turn).

The dimples in the C Frame with hammer were fine as well. A good CFrame dimple vs a good DRDT2 dimple, visually for my eye, I couldn't tell a real difference. I however found I personally produced a more consistent, better looking row of dimples with the DRDT2. I am using Cleveland dies.

I found it is more critical to have the aluminum sheet level with your dimpling surface. Where I had the sheet at a slight angle to the dies or did not have it supported, I produced a poor dimple with any tool I used.
__________________

I couldn't agree more. I too have both the C-Frame and the DRDT. I guess my eye isn't good enough as I can't tell the difference either. The DRDT-2 produces a significantly more consistent dimple.

One other idea would be to have somebody else try the dies in their C-Frame or DRDT-2 and evaluate. Easy to ship and relatively inexpensive compared to many other tools.

Tough way to start, I admire your persistence and patience.

Fred

[vluvelin]

I ordered AVERY tools Dies from ATS must have them tomorrow
and will compare and make some new pictures

[vluvelin]

Originally Posted by flion

All this obsession over the dimples is fine, but what are the finished results? You set the rivet with either gun or squeezer and you think the rivet is the only thing that distorts? The most important feature of good dimples is that there are no cracks around the holes. To me, there is always a noticeable difference between a rivet simply sitting in a dimple and a set rivet - the act of riveting helps the rivet and dimple conform more tightly to each other.

In my understanding if rivet head conical surface do not fully touch dimple
+
Dimple not fully touching underlying dimple ( Nesting )

this situation creates too much empty spacing that getting compressed during riveting this creates unnecessary distortion on skin that can be avoided
and perfect reflection that is achieved by Mike from Cleveland videos
would look all distorted.

[flion]

Originally Posted by vluvelin

Dimple not fully touching underlying dimple ( Nesting )

Now you're opening a REAL can of worms. The tech counselor (since passed away) who came to inspect my RV-6A just prior to final assembly wanted me to scrap the whole project because I had not used airline-style die tooling for all my dimples. (Actually, he just wanted me to dump the plane on the market so he could buy it cheap; thanks to advice from several local A&P IAs, I avoided the trap). I inquired into such tooling. You need different dies for every different thickness and also for every underlying stack, because each underlying dimple must be larger to accommodate the overlying dimple and the size depends on the size of the overlying material. You can guess what a nightmare that would be to keep straight, not to mention the cost.

Fortunately, for the sheet thicknesses used in most of our aircraft, it's not that critical. As for cosmetic results, let's see if the folk who polish their aircraft will weigh in. Otherwise, it's not really worth your time. In some threads that have gone before on VAF discussing show quality aircraft, one thing that stuck with me was that judges want aluminum aircraft to look like aluminum. In other words, the rivets should be visible, even under paint, but not sitting proud or excessively gapped.

Don't let me rain on your parade in search of perfection. It's not a bad thing. But be sure to consider the costs, both in time and money, and don't let it prevent you from finishing your aircraft.

[Electrogunner]

Originally Posted by vluvelin

who sales them today??? where can i get a set???
Can you make high res picture for comparing?

I think cleaveland picked up the Avery stuff. I will be dimpling the fuselage sides in couple days. Will try to get some close ups.

[vluvelin]

Originally Posted by flion

You need different dies for every different thickness and also for every underlying stack, because each underlying dimple must be larger to accommodate the overlying dimple and the size depends on the size of the overlying material. You can guess what a nightmare that would be to keep straight, not to mention the cost.

Yes this is the filling i have!! If most people are happy with 1 size fit all approach you will not find fine-tuned dimple dies in usual places we shop

Originally Posted by flion

Don't let me rain on your parade in search of perfection. It's not a bad thing. But be sure to consider the costs, both in time and money, and don't let it prevent you from finishing your aircraft.

I am not in rush I have Nice Rv7 to enjoy. Building for me is self education
Isn't it what experimental aviation supposed to be???

[rv7boy]

This thread reminds me of a comment made by my EAA Tech Counselor and friend who inspected my empennage. He said,"Don, you need to decide if you're building a showplane or an airplane to fly."

[60av8tor]

Originally Posted by rv7boy

This thread reminds me of a comment made by my EAA Tech Counselor and friend who inspected my empennage. He said,"Don, you need to decide if you're building a showplane or an airplane to fly."

I agree with this sentiment, but not in this instance. Takes the same amount of time to make a poor dimple or a nice one. All things equal, I'll always choose the latter.

[rv7boy]

Originally Posted by 60av8tor

... Takes the same amount of time to make a poor dimple or a nice one. All things equal, I'll always choose the latter.

Jon, what I was referring to was the idea of using different dies for different thicknesses and for every underlying stack, as described in flion's post above. And to quote flion's summary statement, "...But be sure to consider the costs, both in time and money, and don't let it prevent you from finishing your aircraft."