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[December 10, 2005]


Today I went to my old house and picked up my bench grinder and drill press. The drill press was a bear to move...the things weighs a good 150 lbs. Anyways, I lugged those things into my basement and set them up.

I didn't have that much time to work on stuff tonight, so I thought I could at least get the dimpling done on the spars and ribs. I first tried the hand squeezer since I had it setup. I did both right spars with the hand squeezer and my hands were killing me. It then occured to me to break out my pneumatic squeezer. I setup that thing, and did the rest of the dimpling in no time. I have to say that it took me about 10 mins to do two spars with the hand squeezer, and then 10 mins to do all the ribs and the other spars with the pneumatic squeezer.

One bit of advice I got from a bulletin included with my pneumatic squeezer from Clear Air Tools was to NOT hook it up to an automatically oiled line. It stated that the oil would wear away the grease that was in the squeezer. The recommended maintenance is to re-grease when it needs it. When I started using my squeezer, it used significantly less air than the drill does. It makes me understand why the drill needs oil and the squeezer doesn't.

One thing that I notices was each of my dimples had a slight circle on the metal where the dies came together. I do not know what caused this. I tried backing off the distance between the dies, but didn't make the dimples deep enough (I tested with a AN426 rivet). This doesn't bother me too much for the insides of the HS, but I am a little concerned about marring up the outside of the skins.

I asked the following question: 

Hey guys,
I just started dimpling my ribs and spars for my HS and one thing
that concerned me was there was a slight imprint of a circle in the
metal after I dimpled it. I do not remember this from my RV builders
class, but then again, that was a while ago. I tried using a pneumatic
and hand squeezer and I got the slight circle with both methods.

I don't think it is a big deal for the inner parts, but I am concerned
with having these slight circles on my skins when I use a DRDT-2 to
dimple them. Any advice on dimpling the skins with the DRDT-2?

Thanks,

Mike Bullock
http://www.rvplane.com



Responses: 

They are in mine too. Just a small mark in the very soft Alclad,
doesn't penetrate the Alcald though. See it in a lot of RV's. Drive
on!


Les Dial
Manufacturing Engineer Staff
F/A-22 Manufacturing Engineering

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Circle = normal = done right

)_( Dan
RV-7 N714D (721 hours)
http://www.rvproject.com

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You WANT to see the circles. I means you have done it right !! Keep on
pounding !!

Simon
RV7A
PH-SCP (reserved)

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Hi Mike,

You are doing good!

How not to dimple: http://caura.dyndns.org/gallery/How-Not-to-Dimple

Happy Dimpling!

//elson
Austin, TX
RV-7A - Fuselage (center section)

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Mike
Try one a bit looser, with no circle. Hold it up to the light & you will see
that the skin is not flat around the dimple. As everyone has said, the circles
are good!

Bill Swaim
RV7 Slow Build Fuselage
N615KS Reserved



My drill press finally moved into the shop. It is adjustable speed from 380 - 8550 RPM.


Old school craftsman bench grinder.


Using the yokes, it was impossible to get the ends of this one rib...i think it is the outer rib. So I just bent the flanges out, dimpled, then bent them back to perpendicular.


This is my most favorite tool yet! I am glad that I hand dimpled some of the holes first to appreciate how nice this is.

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