Dimple die scratches skin surface

[Michael Burbidge]

I'm having a really difficult time preventing the dimple die from scratching the surface of my HS skins as I move it over from hole to hole while using my C-Frame to dimple. I've built a table for my C-Frame so that the skin is supported as I'm dimpling. I lift the skins as I move it, or so it seems. But I guess not enough. There is still a light scratch between holes. In any event, the skin is just lightly dragging against the tip of the dimple. But the soft alclad surface is no match for the hard tip of the dimple die.

Do I have a bad dimple die? Does anyone have any tips on how to prevent scratching the surface. These are very light scratches in the alclad. It's very annoying!

Someone should make plastic or nylon tipped dimple dies.

[Guy Prevost]

You can try polishing the tip of your dimple die a little better, but in all honesty these scratches are inconsequential. You're going to have 1000s more by the time you are done. Then you're going to take a Scotch-Brite pad or sandpaper to the plane before painting it anyway.

[Mike S]

Sounds like you are using some kind of "C" frame device.

Do you have any kind of flat surface "Table top" around the unit??

A couple of pieces of soft foam, a couple of inches to the sides of the die will keep the skins above the die, you need foam that will hold the skin up, yet compress when you form the dimple.

May take a bit of trial and error, practice on scrap.

This worked for me, using a DRDT2------with a "bang-on-it" unit, you will probably need to use one hand to hold the skin down when you hit the plunger.

Good luck.

[Craig23]

I agree with Guy. My dimple die does the same thing if I let it contact the skins at all as they move to the next hole. The scratches are so light that they are nothing to worry about and by the time you paint the aluminum you won't even notice them.

[docrick]

It is no problem they will buff out or if you paint the aircraft you'll never know they were there.

Build on

[az_gila]

Can you work it the other way round... with the "pin" of the die on top?

Don't use the return spring, and hold up the C-frame set as you move the skin around... gently let the set down so that the "pin" falls in the hole... then whack it!...

This way, you are moving the skin over the polished "innie" die.

If you leave the return spring on... you will have made a good skin punch...

gil A

[Geico266]

Originally Posted by mburbidg@adobe.com

In any event, the skin is just lightly dragging against the tip of the dimple.

Gil has it right, put the tip up in the movable part of the "C" frame and the receiver / button part down.

[AMURRAY]

I agree with Gil. Turn the dimple die over so the male half is on top.
Aaron

[docrick]

Originally Posted by AMURRAY

I agree with Gil. Turn the dimple die over so the male half is on top.
Aaron

I think this would make the process take much longer. With a C frame you would have to be really careful to make sure the male die went into the drilled hole or you'll find an extra hole

This would be a little easier with a DRDT-2 (which I'm fortunate to have and will never part with, at least until my 9a is finished) because you don't have to whack anything with a hammer.

Just don't worry about these little "mars"; they'll buff out. If you don't like those marks just wait until you start backriveting stiffeners on your very thin rudder skins! The back rivet plate will leave little mars as well.

[LettersFromFlyoverCountry]

Boy, there's no way I'd ever turn those dimple dies around, at least if you use the C-frame tool as they come...with the little spring and O ring holding the stem slightly above the work.

Having the "male" poking through the hole is the only confirmation that things are lined up properly.

I'm familiar with the problem you describe, and it is unsightly but as others have stated, inconsequential. Still, you should be able to minimize it by lifting the work off the die more rather than dragging it across it.