<June 17, 2005>

Let the Dimpling Begin!

EDIT: I write this note many years later to let people know that while at one point I favored the Burraway, I cannot recommend its use anymore. I had the blade on mine malfunction (jam) while a friend was helping me deburr a skin, and it totally trashed the skin by countersinking the back side of every hole as he pulled it out. Unfortunately, the unit gave no indication anything was wrong, and it was only upon inspection of the skin that we noticed the problem. I don't think the Burraway is a bad tool, I am just not sure it is good idea to use it on the relatively thin skins that we have in RV kits. As usual, your milage may vary.

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After the past two deburring sessions I decided there has got to be a better way. So after reading some posts on the RV-List(s) I broke down and ordered a Burraway from Cogsdill Tools. The Burraway is a little tool that is used in a drill and inserted into a hole. It deburrs one side on the way in, and the other side on the way out. At $46 it wasn't cheap, but if it cuts down on the deburring time it will be well worth it. I will post a review and pictures here on the site when I get it and have used it.

Anywhoooo, I managed to squeeze in some dimpling tonight. Get it? Squeeze in some dimpling... oh never mind. I used my DRDT-2 from Exerimental Aero for the first time, and when I got in some tight spots I used my hand squeezer mounted in a vice. I also used my new Tank Dimple Die set from Cleveland Aircraft Tool. The Tank Dimple Dies are a little deeper than your standard dimple die and I have heard a few builders say they use them for the understrcture (ribs and spars) so that the regular dimples in the skin fit better in the dimples in the understructure.



The regular -3 die is on the left and the tank die on the right (both from Cleveland Tool). You can just barely see the difference with the tank die being somewhat larger/deeper. In playing with some scrap last week I found it hard to get two dimpled pieces to fit together well, so after do some research, I found that there are many builders that use these to dimple the understructure so that the dimples in the skins fit better in the underlying dimples, so I ordered myslef a set. Normally these dimples are used to make a slightly deeper dimple in the fuel tank skins as Pro-Seal has a tendency to keep the rivet heads from fitting flush, and the deeper dimple compensates for the Pro-Seal, or so I read.

The DRDT-2 clamped to the bench (clamp cannot be seen). I used a step stool to get more leverage.

For those few tight spots where the DRDT-2 wouldn't fit (noses of ribs and outerholes in spars), I used my squeezer mounted in a vice. This actually worked pretty well.

All of the internal HS parts ready to be cleaned, and primed... oh yea, I still have to deburr the skins... yuk.