Tip: Alternative Dimpling Technique

I wanted to install a terminal board to a side skin. To do so required dimpled holes in the skin to accept #6 screws. At this stage of assembly using a C-frame, pneumatic or hand squeezer is out of the question. Close quarter dimple sets used with a pop rivet tool simply do not produce dimples as "sharp" as regular dimple dies. These particular dimples are in a highly visible area so a better technique was desired.

The problem was solved by drilling .1895 holes into a bucking bar and an old rivet set. Even using my floor mounted drill press, it took some doing to produce those holes! Still, using these slightly modified tools, any of the dimples in our collection will have even greater utility when fitted to a rivet gun. Cleaveland and Avery Tool...are you listening?

Good job on rolling your own but Avery and ATS love your idea, they make such tools already...Not sure about Cleveland...





Also, my old C-frame tool is designed so that the parts that hold the dimple dies can be inserted into a rivet gun. Don't remember what brand (I think it is the Cleveland Unit) it is and I bought it about 7 years ago. You can use the bottom set holder as you did with the set you modified.

How about a pop rivit dimpler?


http://www.averytools.com/cart/p-857-pop-rivet-dimplers.aspx

How about epoxy?! Or even proseal...

I gave up.

Rick,

I missed dimpling a few holes behind the aft cabin bulkhead, so I tried the same thing with one of my bucking bars. After drilling on the bucking bar for several minutes without hardly making any progress, I abandoned that idea. I ended up with some sort of convoluted setup involving a 2x4 (don't ask). So, how long did it take you to drill this hole, and how many drills?

Tracy.

thallock said:

Rick,

I missed dimpling a few holes behind the aft cabin bulkhead, so I tried the same thing with one of my bucking bars. After drilling on the bucking bar for several minutes without hardly making any progress, I abandoned that idea. I ended up with some sort of convoluted setup involving a 2x4 (don't ask). So, how long did it take you to drill this hole, and how many drills?

Tracy.

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I did the same thing. Took 1 drill bit and about 2 minutes. The key is to use a drill press at 250-300 rpm and lots of lube. If you run it faster than that or use a hand drill, your drill bit overheats, gets dull, and doesn't drill anymore.

Mine is about 3" square and 3/4" thick and has holes on the flat a couple of the sides to get into various sized areas.

PJ Seipel
RV-10 #40032

PJ,

Thanks, I may try to drill the hole again. I think this is a useful tool to have.

Tracy.

dan said:

How about epoxy?! Or even proseal...

Click to expand...

I'd use GOOP . . .

DGlaeser said:

I'd use GOOP . . .

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The old Shoe Goo, now sold under its spec name of E6000. It can be found in Walmart or craft stores.

I don't know if I would trust a 13 curcuit terminal board to E6000. 26 dangeling wires can really pull on the adhesive, especially under G and vibration.

Instead of drilling a rivet set, you use the plunger from your C-frame (if you're so equiped). Strike with a mallet or ball peen. I do back riveting when I can with a hammer instead of a gun. more control of the work piece and process IMO.

I find the pop rivet dimplers do a great job. Might try pulling until the nail breaks to obtain a sharper dimple. I use ATS brand so maybe there is a difference in end results.

Jekyll

thallock said:

.......... So, how long did it take you to drill this hole, and how many drills?.........Tracy.

Click to expand...

Tracy,

Actually, I only used a few drill bits, a #30 for the first pass, a #21 for the second pass and finally a .1895. Using 250 RPM, the work was literally bathed in cutting oil which sometimes even started to boil. The drill press allows you to apply much more force to the work than a hand drill can and I was ever mindful of snapping a bit off in the work which would be a real nuisance to deal with. Occasionally, I would remove the work from the drill press and quench it in cold water. Eventually, the process produced good holes.

I had no idea such dimpling tools are available. If I did know, I would likely have purchased instead of making them. As it is, it worked out okay the way it did and I saved a few bucks in the bargain.

Soon, I will find another use for the technique. Similiar to my 6A, I plan on fashioning a sort of simple rack to support and mount the AOA computer. Using a screw pattern to securely fasten the mount in place to the bottom skin seems a more substantial practice than opting for materials such as epoxy or proseal and may be more in keeping with accepted practices outlined in AC-43. Besides, if I ever want to remove the mount (or terminal strip) for any reason, screws are much easier to deal with than removing and cleaning away permanently bonded materials. Unlike the installed AOA module component in my 6A, I will use the method outlined here instead of dimples set with a pop rivet tool.

works like a charm

i did this a while back and it does work great. but you better drive straight. i found the pop rivet dimple to work as rick said. however once you shoot a rivet in there witha soild flush set they look the same to me. oh, i only used one bit to drill my parts.

shootin' dimples

i've done this as well. works a treat, as the brits would say. i only had to drill the hole in the buckingbar, 'cuz when i bought my used tools there was already a set with a hole in it (i probably wouldn't have thought to do this if there wasn't.) i only used one bit for the hole -- in the drillpress with slow speed and lot's of liquid boelube.

if you don't want to sacrifice a real rivet set, the "chisels" from a harbor freight $7 air-hammer are .406 (i think that's the right size -- anyway, they fit in a rivet gun), so you can sacrifice one of those.

Homemade set

I'm embarrassed to admit that I dimpled my entire HS and VS skins using this method back in '84, but it worked great w/o damage.
I've made several set holders of various lengths for my 3X gun using 1/2" steel rod, available at hardware stores. I grind the .4 diameter on the bench grinder and clean up on the belt sander. The tip is easy to drill for the rivet set. Since it's not heat treated it wouldn't do for thousands of rivets, but it works fine for those special occassions.