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  #1  
Old 02-11-2021, 12:33 PM
ronshort2000 ronshort2000 is offline
 
Join Date: Oct 2020
Location: CATAWBA, SC
Posts: 7
Default Dimple with Numatx - Help

Hey y'all. I've been lurking for a couple of years but finally decided to start the RV-10. The last tool came in today (DRDT2) and should order the Emp kit after Synergy Air next month. Or maybe after I actually look at one at SUN 'n FUN, if Vans has one there.

I have been working on the practice kits, and thank good for that. Steep learning curve but have been loving it. I have a Numatx squeezer with Cleveland dies. The problem I am having is that after doing the dimple, the sheet of aluminum is curving, with the female die side being concave. I have the input PSI set to 90 psi, I think I read somewhere that is the right pressure. The dimples look good, as far as I can tell, except for the curvature.

I also notice that when I squeeze a rivet or dimple, the 3" yoke tends to bend a little from the force. Is that supposed to happen or do I need to reduce the pressure.

Thanks in advance for the help and I look forward to spending more time interacting on this forum.
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  #2  
Old 02-11-2021, 01:16 PM
1001001's Avatar
1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 1,128
Default

I have always had problems using a squeezer (pneumatic) to get perfect dimples. I have tried a variety of different gap settings and have not been able to get crisp dimples with squeezers.

My DRDT-2 produces the best dimples of all tools I have tried. Anytime I need to dimple I use it, unless for some reason I can't get the part in it. I only use the squeezers to dimple when it's impossible to use the DRDT-2. I have used the standard C-Frame as well, but my DRDT-2 does even better.
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  #3  
Old 02-12-2021, 03:18 AM
Patrick14 Patrick14 is offline
 
Join Date: Feb 2018
Location: Mainz, Germany
Posts: 22
Default Use the C-Frame Tool

Hi,

i (and many others) had the same problem. I could not resist in buying the hydraulic Numatx and it is a great tool for setting rivets with a constant result. I thought i would get along with just one tool.....
Unfortunately even if you put on the max pressure of 90psi it is not enough force compared to the impact of 2 hammer strokes with the basic c-Frame. I ve read a lot about it and my resumee is that even the DRT2 doesnt work as well. So i ended up with buying the c-Frame via ATS. The first one was damaged, the second one needed some rework to get excatly adjusted, but it works very good now. The dimples are very sharp and crisp. There is a video from Cleaveland tools on you tube adressing this. Especially the light reflection test.
For substructure (ribs, spars) i use the substructure dimple dies with a slightly different form and the numatx.

If i would do it again, i would still buy:
- the numatx for riveting in accessible places,
- the rivet gun for the unaccessible places,
- the C-Frame from cleaveland for most dimples
- blindrivet-dimple dies for close quarters and unaccessible places



Build on!

Patrick,
Germany
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  #4  
Old 02-12-2021, 10:23 AM
abwaldal@gmail.com abwaldal@gmail.com is offline
 
Join Date: Jan 2017
Location: Battle Ground WA
Posts: 171
Default

I have a Numatx and agree with others. It's great for riveting but if you want crisp dimples even in .063 (which you are not supposed to dimple) you need the bashing of a hammer with the C-frame or what ever. Extruded force like pneumatic tools and the DRDT-2 don't do it.
I have all the tools known to mankind for this type of work and the dead fall hammer still gets it done better. Ya I know you have to get it into the C-Frame.
That's the fun of building.
Art
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  #5  
Old 02-12-2021, 12:24 PM
1001001's Avatar
1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 1,128
Default

Quote:
Originally Posted by abwaldal@gmail.com View Post
I have a Numatx and agree with others. It's great for riveting but if you want crisp dimples even in .063 (which you are not supposed to dimple) you need the bashing of a hammer with the C-frame or what ever. Extruded force like pneumatic tools and the DRDT-2 don't do it.

Here's what I don't get. So many people say the DRDT-2 doesn't work for dimpling (especially heavy stock), but I have zero problems with mine. Did I just get a really good one? Is it a setup problem for others? Why does mine work so well, while others have issues?
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  #6  
Old 02-12-2021, 01:10 PM
ronshort2000 ronshort2000 is offline
 
Join Date: Oct 2020
Location: CATAWBA, SC
Posts: 7
Default

My DRDT just showed up yesterday so I am anxious to set it up and try it. I paid extra for the Numatx and DRDT so I sure how they work and save time and effort. Not sure how much I like the foot pedal for the Numatx but I am sure I will get used to it.

I will be in the shop this weekend doing more practice kits so I will compare the different dimpling and riveting methods to see how consistent and easy they are. My bucking definitely leaves a lot to be desired, but I have only driven about 10 so far. I am sure I will get the hang of it.
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Working on practice kits
Plan to order RV-10 Emp spring 2021
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  #7  
Old 02-12-2021, 08:51 PM
Moresushi Moresushi is offline
 
Join Date: Dec 2018
Location: Spring, TX
Posts: 17
Default Dimple with Numatx

I have the NUMATX Squeezer system with their yokes. I'm using Cleveland dies. I found that if I use a thin washer as a shim for the dies, set at 90 psi I get good dimples. Maybe some of it's due to a cheap pressure guage??? I also use a DRDT-2 whenever I can. I tried the C-Frame and hammer but I wasn't happy with my inconsistent results.
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Spring, TX
EAA Chapter 302 Member
KCXO Conroe, Texas
RV-10: Under Construction
https://eaabuilderslog.org/?blproject&proj=7Wk8ZhOko
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