Drill Size For Dimpled -4 Rivet Holes

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GESchwarz

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Oct 23, 2007
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1,222
Location
Ventura County, California, USofA.
I've noticed the after dimpling a #30 hole, the the diameter of the hole opens up, making for a loose fit for the -4 rivet.

Should I drill thes holes with a 1/8" or #31 or #32 drill so as to have a tighter hole and stronger attachment?
 

Captain_John

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Feb 3, 2003
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699
Location
KPYM
Gary,

Nope... you are doing things right.

That is normal.

What I often do is crisp things up a bit by just touching the deburring tool to the interior portion of the dimple.

It really makes for a flush, smooth product.

:) CJ
 

LArzfromarz

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Aug 17, 2009
Messages
95
Location
Sunny Central FL
The metal stretches when dimpled so it will open up.
Just curious-
What application calls for dimpling before riveting?
I'm a "certified" guy and haven't seen this before.
Larry
 

MadRocketScientist

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May 16, 2009
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Location
Canterbury, New Zealand, Earth, Milky Way Galaxy.
My whole aircraft is 0.020" and 0.016" so I have a few dimples to do as I am flush riveting the whole thing.

I have heard of people using a microstop countersink to make the dimpled holes fit the rivets even better. Just don't remove any more the smallest amount of material.

Shannon.
 

heytwo

Member
Joined
Sep 30, 2009
Messages
5
Location
Arizona
10-4!
I'm just used to .032 maybe .028.
Larz

Its not "structural" to use 3/32 AD rivets in .032 .
You must use a "ratio" of rivet diameter to skin thickness.
You cant simply increase the number of rivets .

I will do some wing spars with .080 , it can use 5/32 AD's
or 3/16 ..but not 1/8" AD's .

In the late 60's , i did some stretched
Beachcraft , tri-pacers in Tucson and they ordered me to
use 1/8 AD's in 5 layers of .032 2024-T3 . BAD !


I did Hot dimpling in .032 , maintains the 60,000 PSI
UTS of the metal . Alum' was forced around a 1/8"
pilot , made a perfect .128" rivet fit

Use tiniest cable , about 3 inches long .
push both ends into a 1/4" steel tube , smash tube .
Chuck it in 3/8' drillmotor to deburr
aircraft skins .

Where can i get 2024-T3 ? Wing spars .
Clecos cheap ?





Edwards AFB . A-11 with green tires , laboring to
get off .. The very first BlackBird .

Rocket test sled at over 4000 MPH ..
Vaporized Aluminum ! I saw the booster out of
my R eye ,and the cloud of dust from my L eye and
of cource the boom , breaking the sound barrier .

No water to slow it , it was just to waste
the left behind equip , that was not sent to new sled
facility in NM .
Then the time i raised a AGE cart tongue too fast
and dented a B-58 Hustler elevon ..Ouch honeycomb .
 
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