What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

How do I drill between wing wall ribs conduit?

bobmarkert

Well Known Member
Using the search function for ?conduit? ?Rib Holes? (etc. etc.) flooded my computer with a ton of posts but no solution for my dilemma. I need to drill conduit holes (3/4?) in my wing ribs that are already riveted to the front and rear spar. No issues until I got to the wing walk ribs which are too close to allow the unibit and 90 degree drill in. I can?t be the first to have this problem. What new tool do I need to buy :)
Solutions/suggestions appreciated.

rib2l.jpg


rib1y.jpg
 
I remember doing this on my QB wings, which was even more difficult. I used a unibit extension, but one that I found locally. I also customized my unibit.

All the unibits I had produced too large a hole if I ran it all the way through - so I could reach the next rib. My solution was to buy a cheap unibit at Harbor Freight and grind off larger diameter steps in the unibit.

This way the max size of the unibit was equal to the desired hole size. This way I was able to use the extension and move from rib to rib without too much hassle.
 
Thanks Fred and Rick. I DO owne that extension tool and will grind my unibit down today. I love this site....... build on!
 
Don't grind your unibit. Slip it into place and then put the extension on. Drill your hole then take it apart. You only need to do it a couple times.
 
Most of the times that I need a 3/4" hole in aluminum sheet, I use a spade bit intended for wood. But only the ones with points on the corners of the spade seem to work in that application.
 
Looks like Bob already has the solution but for those yet to come down this road.....

I used Lowe's Aviation supply extension and ground down a unibit to fit the Lowes's underground sprinkler system tubing (Light weight).

de5pgx.jpg


2v0db3p.jpg


2nicx0n.jpg
 
Last edited:
Thanks guys. I could not see the forest for the trees. This was so simple it's embarrassing. Just 5 minutes with a grinder and I was done.
Again you came through!!


imagejyq.jpg


imagehoqp.jpg
 
I did the same, welded socket on rod

I purchased a 6 ft rod from Home Despot and welded a socket to the end of the rod to accept a 1/2 in unibit. The unibit was not modified. I drilled the wiring holes in the wing from each end. A 6 ft rod is just enough. I use snap bushings, no conduit, in the wings.
 
I need to drill some holes for wiring in the seat ribs. No way to get a long extension to work in there, since you can't come in from either side unless you drill a hole through your fuselage side skins :eek:

I bought the cheap unibits from Harbor Freight and with a little grinding off of the hex drive end I was able to chuck it into my angle drill adapter.

IMG_2044-M.jpg


This has come in handy several times in the build. Crotch strap anchor bolt holes are another place which this tool worked out.
 
Irwin speedbores

for drilling conduit holes in wing ribs an Irwin speedbore works great!
You can extend them with any 1/4 inch hex extension and go the distance.
they are self-centering and the ears on the speedbore bits make clean cuts in the aluminum.

Jim Frisbie
RV-9A 250 hrs flying
 
Air powered ratchet

Hi gang, another option is a air powered ratchet with the correct socket for the unibit. I've used mine a few times in tight spots, works well.

Terry
 
I note in the pic with the 3/4" PVC thin wall water line conduit, that it is installed near the top skin.
I drilled mine in near the bottom skin. My plans don't refer to wing conduit, so I just picked a route. The 3/4" PVC met all my needs for Archer antenna, position, landing & strobe lights.
Right now I'm thinking the best way is as pictured, near the top. It was a fair bit of work pulling in the wires and routing them under the control column.
 
I used a "rotary broach" ...

...purchased from Avery Tools. I'm a little late to this discussion, so maybe not too helpful. All of the methods described above work fine. My solution required only drilling and threading with tools I already had on hand. and did not take too long to make.

I purchased a 3' long rod. Drilled a 3 - 4" deep bore hole for a pilot drill in one end.

Next I cross drilled the rod and threaded the cross drilled hole for a set screw to retain the pilot drill.

The I threaded the outside of the rod for the rotary broach. I spun on two jam nuts first, then the broach. I had to grind down the corners of the jam nuts so the corner-to-corner dimension was less than 3/4".

There is a hole to locate the rib in the forming die during manufacture that I used as my pilot hole. I put all the 3/4" holes in my QB wings this way. Drilling the holes was even faster than making the tool.

Larry Tompkins
N544WB -6A
W52 Battle Ground, WA
 
Back
Top