Question: Dimpling Screw Holes in Tanks

[Stockmanreef]

In the plans (RV-14) it says to use a C-frame and hammer to put in the dimples for the screw holes in the tank skins. Apparently this makes crisper dimples. I assume that a pneumatic squeezer will work for the job. I don't have a C-frame. I do have a hammer, but I think that the c-frame is the critical part of this exercise ;-).

Thanks
Ken

[N941WR]

Check with Froggy, Pat, or one of the other RV builders there. They can give you a hand and might have a C-frame you can borrow for those few dimples.

The C-frame simply holds the dimples in the correct relation to each other.

The trick is to get the dimples, not so much what tool you use to get them. The tank skins are thicker than the rest of the skins, as you have probably noticed, thus dimpling them takes a bit more force. When I did mine, I found that using hand squeezer didn't produce as nice a dimple there as using the C-frame.

Best of luck!

[wirejock]

I'm not familiar with the thickness of the 14 tank skin but my 7 skins are thick.
Personally, I would seek out a c-frame within the Chapter or this community.

[rvbuilder2002]

The reason behind the manual recommendation is somewhat explained in Section 5.5 of the Newly Updated Section 5 of the construction manual. You can find a copy HERE

The tank skins are a worst case situation...
Thick skin and large dimple size.
This combination requires a lot of force to form a crisp dimple. And they are right along the edge of a skin which you want to lay down nice and flat.
Most pneumatic squeezers don't have enough force, and even if it does, the yoke flexes causing a misalignment of the dies which ruins the dimple quality and makes for a wavy skin edge.

More info and discussion HERE in a recent VAF thread.

[Stockmanreef]

OK. I understand the issue. What if the pneumatic squeezer is in a C-frame? I have a monster steel tube Cframe with a Numatx hydraulic squeezer that I can attach to it.

It might also be possible for me to make something that I can use to hold a die and then use a hammer.

Thanks for the feedback.

ken

[JanRV6UK]

Ken .. Why not try to make a dimple on a piece of scrap alu of the same thickness ?