J

Jalanci

Member
Finished the horizontal stab and working on the vertical today. Alls well, except I'm finding a couple of loose cleco'sm when I prepare for riveting. I'm guessing the dimples stretched the hole some using a pneumatic squeezer. I drilled the two out that felt too loose to #30 and placed oops rivets instead. Any other suggestions, is this overkill?

Thanks in advance. Any advise on dimpling technique to prevent the hole stretch?
 
Hi Jeffery,

After dimpling I found the holes in the skins to be slightly larger than before. The thinner the material is that is dimpled, the larger the change in the hole size. Just wait until you do the rudder and elevator skins. They open up more then you've seen already. As long as you are using the correct die set, you should be good. I used a hand tool for the dimpling and had no trouble. Using reasonable pressure with a hand tool, you can't over dimple a hole. Once the die is fully closed it can't dimple more. I've never used an air dimpler but I can't imagine it can over dimple either.

I just don't know why this would be a condition that would cause only a few holes to be different from the others. Does the loosness feel the same with other clecos in the same hole or is the loosness from a cleco that is different from the rest?

When the rivet gets driven it fattens up slightly to fit the hole. So long as the hole isn't wacky big, I think you should be fine.
 
Hole size

The issue was only a couple of rivet holes. I'm fairly sure that the AD3 would squash and fill the hole, but figured that if I replaced the rivets with the larger ones, I'd be sure of a good fit.

I used a couple of homemade washers to get a better grip on some of the cleco's. Two holes wouldn't grip at all so I chose a conservative route. Appreciate the insight though.
 
I had the same problem

It might be your clecos, not your dimpled holes.

I had the same problem, except that none of my cleclos would hold in place after I dimpled my skins. Needless to say, I panicked. My tech advisor came over and said the holes looked normal to him and couldn't see why the clecos wouldn't hold in them. I borrowed some of his clecos, and they all held just fine! For some reason, the clecos I had bought would not spread out quite as far as his clecos. We still haven't figured out why, but I've since sent all of my clecos back to US Industrial Tool. Mike Hill, their technical manager, is testing the clecos to try to figure it out. In the meantime, I'm using my tech advisor's clecos and everything is holding fine.

Bad Clecos?


Craig Vincent
RV-9A emp
N51CV
Stockton EAA
 
Are all your clecos the same brand?

3/32" Clecoloc brand will not work after dimpling.
 
Not all clecoes the same.

I accidentally ended up with two different brands of cleoes, so I divided them up and use the smaller ones on the prepunched hole assemblies, where they go in much more easily, and the larger ones after things have been dimpled. No need to go all the way out to an oops rivet. Fortunately, the "little" ones have a plated shank and the others do not, so it's easy to tell them apart, at least in my case.
 
Thanks

I do have two sets of cleco's from two sources. The last bunch I bought from Van's, hopefully, they will hold. I'll check the diameters and see if I find a difference.

Great help, THANKS!!!
 
briand said:
Are all your clecos the same brand?

3/32" Clecoloc brand will not work after dimpling.
Click to expand...
I have had the same problems with the Clecoloc brand. I cannot remember the brand name of the other type of fasteners I also have. I bought them at Oshkosh from Avery tools a couple of years ago. This other brand has a pewter (sp?) colored button rather than the silver color of the Cleco brand. Whenever I need to cleco a dimpled hole I use these to do the job.
 
differing grip lengths

If you study the business end of your clecos you'll notice that different brands have slightly different spreader bar lengths. If the spreader is very short and the thicknes of the material too great, the two little gripper fingers don't get spread apart as the cleco spring is released.
Since the dimpled holes are now "thicker" than the undimpled sheets, apparently your clecos are not retracting enough to be spread apart and they fail to grip.

At least that's my story and I'm sticking to it.

-mike
 
I've had the same problem with the Cleco brand cleco. (Silver top). They will not hold consistently in a dimpled hole. The WedgeLock brand (grey/pewter top) from Avery have never given me a problem.
 
use #41 or 3/32"

Are you match-drilling with #40 or #41? I believe the standard is #40, but I switched all my tooling to #41 long ago. I think you'll like your holes better with #41. You might even go to a 3/32" if you're still getting holes too large. You want to use the smallest hole that will still allow you to get your dimple die pilot (and subsequent rivet) into the hole.

Avery now sells #41 reamers, which in theory make for better holes.
 
brian said:
Are you match-drilling with #40 or #41? I believe the standard is #40, but I switched all my tooling to #41 long ago. I think you'll like your holes better with #41. You might even go to a 3/32" if you're still getting holes too large. You want to use the smallest hole that will still allow you to get your dimple die pilot (and subsequent rivet) into the hole.

Avery now sells #41 reamers, which in theory make for better holes.
Click to expand...
To anybody out here who thinks #41 works "better," here is why you should NOT use a #41. I had a conversation with Fred Kunkel from Clear Air Tools about tolerances, and the way he described it is a terrific way to think about it. Here goes...

Every "precision" tool we use is manufactured as precisely as possible...giving the manufacturers tons of credit here. But all drill bits are not created equally...even those of the same size from the same manufacturer. There are tolerances used in the manufacturing process. It's always a "plus or minus" some small amount that is considered acceptable.

Now let's say for the sake of argument that you're using a #41 drill bit that happens to fall on the SMALL side of the tolerance window. And let's say your dimple dies happen to fall on the LARGE side of the tolerance window. What happens? Exactly...the dimple die size can exceed the size of the hole. Best case, it juuuust barely fits, but the material around the perimeter of the hole would be STRETCHED more so than if you had just used a #40 drill bit.

These tools are designed and intended for use as a "matched set" with each other, within a certain tolerance range. These ranges work with each other, not against each other. And when you start "overthinking" things and start SLIDING THE TOLERANCE WINDOW around, then all bets are off.

ARE YOU IMPROVING THINGS by going with a #41 drill bit? ARE YOU 100% SURE?!
 
Loose Clecos

Guys,
Use a #41 drill for holes that you are going to dimple. For you pre- punched, matched hole types just de-burred and dimple Van's holes. No more loose clecos
 
Also want to add... As people have noticed, some crummy clecos out there are on the small side of the tolerance range. They work great with plain old #40 drilled holes, but not so great with #40 DIMPLED holes. When you dimple, the hole expands a bit, like it or not.

Are you fixing a cleco problem by re-engineering the hole? Silly! :rolleyes:
 
dan said:
Also want to add... As people have noticed, some crummy clecos out there are on the small side of the tolerance range. They work great with plain old #40 drilled holes, but not so great with #40 DIMPLED holes. When you dimple, the hole expands a bit, like it or not.

Are you fixing a cleco problem by re-engineering the hole? Silly! :rolleyes:
Click to expand...

Hate to say it Dan, but you're sorta talking out both sides here. You're telling me that the tools are all designed to work as a matched set, but then saying that the cleco is an exception to this.

I built darned near the whole thing with 41's and the dimple dies fit in just fine. Perhaps I got lucky and had slightly small dies and slightly big drills. I will admit that my countersink pilots do not like to fit in a 41 hole though. In case anybody is interested, I just mic'd some stuff and here's what I learned:

rivet: .0938
die: .0935
41: .0950

The 41 drill actually would probably produce a hole more like .0960 which will easily accept the die. The 40 drill would be 2 thousandths bigger.

Having said all this, I agree that some clecos really don't work worth a darn on dimpled parts whether you use 40 or 41.
 
I almost always use a #41 drill bit to produce 3/32" dimples. That .002 difference seems to improve the gripping power of my clecos and the rivets tend to set consistently better when bucked into its slightly smaller dimple. Now I know that Van cautions against the natural temptation to simply dimple through a matched hole without reaming it first and I tend to agree. Without some reaming, you have to FORCE the dimple through the hole and stretching will occur. I take it as an article of faith when Van claims that later on, maybe years later...stress cracking can radiate from such holes.

I am not advocating that anyone deviate from Van's instructions, only that is it is my observation that when reaming skin holes with a #41 drill, it IS obvious that some material is being removed and the dimple will not have to be forced through the hole. Still, I continue to use a #40 drill bit when reaming the anodized spar holes because its material is more brittle, machine countersunk, and a 3/32" rivet tends to fit almost too snug in a .096 (#41) hole though the spar.
 
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