Van's Air Force
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Broke another one
- Thread starter Av8torTom
- Start date
Birkelbach
Well Known Member
Somethin' ain't right. You shouldn't break those at all. I still have the first one that I ever bought and it looks brand new after 10 years. Is this with a C-Frame? I assume so since you said "pounding." You might want to check the alignment of the C-Frame. The other Phil 
has a good suggestion too. Might be the female die.
has a good suggestion too. Might be the female die.Are the holes drilled with a #40 drill?
your senstivities are right - this is not normal. I built our airplane and have been doing mods for years over a 16+ year period and it is still in new condition. If you are pounding the die into undersized pilot holes that could be a problem. The deformation pressure is so light there is no way you should ever break a dimple die if every thing is right. When you bought the replacement did you get a new set or just the male die. To actually break that tip off there has to be a side load of some kind in the process. Something is wrong and you should back off production until you find the cause.
Bob Axsom
your senstivities are right - this is not normal. I built our airplane and have been doing mods for years over a 16+ year period and it is still in new condition. If you are pounding the die into undersized pilot holes that could be a problem. The deformation pressure is so light there is no way you should ever break a dimple die if every thing is right. When you bought the replacement did you get a new set or just the male die. To actually break that tip off there has to be a side load of some kind in the process. Something is wrong and you should back off production until you find the cause.
Bob Axsom
larrynew
Well Known Member
The bottom plate on a c-frame is adjustable and can loosen (mine did during the wing build). Causes the dies to not line up.
http://www.cleavelandtoolstore.com/prodinfo.asp?number=CF80
http://www.cleavelandtoolstore.com/prodinfo.asp?number=CF80
FresnoR
Well Known Member
I broke a couple of them, turned out there was a mistake with my technique.
I would get into such a grove pounding the dimples into the skin, I would start to lift the skin a millisecond before i was finishing pounding, eager to move onto the next one, this would ever so slightly (were talking thousandths of an inch) misalign the dimples and my pounding would weaken and eventually break them.
I am not sure if that is what is happening with you, but try checking that out.
Also, if you put the male on the bottom, then the large skin piece could be putting lateral pressure on the die which could also misalign it.
I would get into such a grove pounding the dimples into the skin, I would start to lift the skin a millisecond before i was finishing pounding, eager to move onto the next one, this would ever so slightly (were talking thousandths of an inch) misalign the dimples and my pounding would weaken and eventually break them.
I am not sure if that is what is happening with you, but try checking that out.
Also, if you put the male on the bottom, then the large skin piece could be putting lateral pressure on the die which could also misalign it.
I'd also back way off on the ''pounding'' part..
and start back with minimal strike on some test aluminum and build up to just the amount of hit to make the dimple. It doesn't need that big ole slam with a 4 lb sledge. A super hard hit will also transfer any slightest mis alignment to a lateral force on that little ol baby tip....
You will also find out the hard way when pilot countersinking a #40 if you exert any kind of lateral motion with the drill.... that 3/32 point doesn't take too much lateral force to break off. I quickly learned I was hitting too hard.
and start back with minimal strike on some test aluminum and build up to just the amount of hit to make the dimple. It doesn't need that big ole slam with a 4 lb sledge. A super hard hit will also transfer any slightest mis alignment to a lateral force on that little ol baby tip....
You will also find out the hard way when pilot countersinking a #40 if you exert any kind of lateral motion with the drill.... that 3/32 point doesn't take too much lateral force to break off. I quickly learned I was hitting too hard.
After I spoke with the good folks at Cleaveland, I learned a couple of things:
1. I was just pounding away as soon as the mail probe made it through the hole. It was suggested that I should use my hand to hold the female die down on the sheet before pounding it. This way, the two halves of the die would be aligned before striking. Funny how almost everyone I saw in the videos didn't do this.
And, 2. The die halves were misaligned anyway but they were easily adjusted. In fact, even though Cleaveland was apologetic about their having shipped a misaligned C-Frame, I was was embarrassed that I hadn't checked it out when I first set it up.
1. I was just pounding away as soon as the mail probe made it through the hole. It was suggested that I should use my hand to hold the female die down on the sheet before pounding it. This way, the two halves of the die would be aligned before striking. Funny how almost everyone I saw in the videos didn't do this.
And, 2. The die halves were misaligned anyway but they were easily adjusted. In fact, even though Cleaveland was apologetic about their having shipped a misaligned C-Frame, I was was embarrassed that I hadn't checked it out when I first set it up.
longranger
Well Known Member
For the price of a dozen you could buy a DRDT-2!
Seriously... have you checked for play between the rod and bushing? It wouldn't take much for the dies to misalign.
WingsOnWheels
Well Known Member
Before I got to the second page this was going to be my suggestion. I always push the female die down onto the male die/sheet before I hit it. There is always just a little bit of play on the bushing and no matter how hard you try you will always side-load the shaft a little bit. Plus it keep the sheet from lifting and you don't waste energy when the saft bings in the bushing.
clevtool
Well Known Member
I see you found the problem, but for others reference... If the dies are starting to stick together, it is likely that the tool is misaligned. The male contacts the funnel of the female and it deforms the pilot a bit each time. Before long this makes the dies act like a snap.
