Dimpling with DRDT2

[birddog486]

I've used the cleaveland hand squeezer and my pneumatic squeezer mostly for dimpling ribs and interior parts and pieces so I'm not sure if those are better dimples. I never gave it much thought but I'm thinking now there must be an issue with the dies.

I'm going to find a local builder an try these dies in a c-frame to confirm.

[auburnaviator]

Keep us updated with what you find out. Inquiring minds want to know the results.

[tims88]

After seeing this thread I took a look at the rivets in my finished rudder, which I did with the DRDT2 and the Cleaveland dies, and they look about the same as the ones in the original post. I have a C-Frame as well so I decided to try a test of my own.

Here is a rivet sitting in a dimple made by the DRDT2 at the same pressure I just used to dimple both of my horizontal stabilizer skins:




And here is a rivet sitting in a dimple made by the C-Frame and a .5 pound rubber mallet that I whacked it with a couple times:


I don't really see much of a difference between the two rivets, however I've used the DRDT2 exclusively on my build so far so I haven't really learned how hard to hit the C-Frame to make the perfect dimple. So just to be sure, I decided to grab a heavier steel hammer (20oz) and hit it pretty hard 4 or 5 more times. I think the rivet MIGHT look a little better, but not enough to make me want to beat up the skins that much every time I need to dimple it.



Again, I haven't really used the C-Frame all that much so if others who have used the C-Frame extensively have rivets that look better than what I just did, then I will blame mine on user error

[Dan Langhout]

http://www.vansairforce.com/communit...07&postcount=3 is a link to a post (with photos) I made back in 2009 on this subject. Basically I found that using 1 turn of preload on the DRDT-2 gave excellent results.

Originally Posted by tims88

After seeing this thread I took a look at the rivets in my finished rudder, which I did with the DRDT2 and the Cleaveland dies, and they look about the same as the ones in the original post. I have a C-Frame as well so I decided to try a test of my own.

Here is a rivet sitting in a dimple made by the DRDT2 at the same pressure I just used to dimple both of my horizontal stabilizer skins:


And here is a rivet sitting in a dimple made by the C-Frame and a .5 pound rubber mallet that I whacked it with a couple times:


I don't really see much of a difference between the two rivets, however I've used the DRDT2 exclusively on my build so far so I haven't really learned how hard to hit the C-Frame to make the perfect dimple. So just to be sure, I decided to grab a heavier steel hammer (20oz) and hit it pretty hard 4 or 5 more times. I think the rivet MIGHT look a little better, but not enough to make me want to beat up the skins that much every time I need to dimple it.



Again, I haven't really used the C-Frame all that much so if others who have used the C-Frame extensively have rivets that look better than what I just did, then I will blame mine on user error

[RussellT]

In my experience using a rubber mallet or other soft type hammers wont produce a clean crisp dimple as the cushion effect is too great. As a first time builder and starting on the HS I used a soft hammer for dimpling, I thought they looked fine until an experienced builder pointed out the very slightly rolled edges of the dimples and suggested I use a hard steel hammer. The difference is noticeable and I was pleased he set me straight.
I use a small steel hammer, hold the pin in the C frame and 2 firm but not too hard taps, you will feel the dimple form and a 3rd tap will ring and it is done... There is potential obviously to cause damage to the aluminum with excessive force.

[vluvelin]

are not Loading

[tims88]

Originally Posted by vluvelin

are not Loading

I think I got my picture links fixed.

[wilddog]

Tim,
Both those dimples just don't look right. Are you sure you have the correct dies? When the DRD2 is set right the frame should flex some when dimpling. But they both look off, that is why I'm questioning the dies.

[tims88]

I am using Cleaveland dies that say CAT426-3 on the side of them so they are the right dies for the rivets. I have some older dimple dies from another builder that I did a quick comparison with on the DRDT2. I set the DRDT2 so that it was a 1/4 turn past where the dies are touching when the ram is fully extended, like the instructions say to do which does cause the frame to flex a little when dimpling. The rivet definitely fits better into the dimple made with the older die....



I even tried putting the new dies into the C-Frame and hammering the heck out of it to see if I could get the rivet to sit in the dimple as well as it does with the older dies but no luck.

[birddog486]

I met with an A&P IA thats been building airplanes for almost 50 years and he didn't see any cause for concern with the rivets and the slight gap around the head. He has multiple dimple dies, some produced a dimple like the cleaveland dies and others didn't have the slight gap at the edge. He dimpled with my cleaveland dies in his squeezer and a c-frame and visually they looked the same.

I'm waiting for a new set of dies from a different vendor to show up so I can compare on my DRDT2