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Drilling Wing Rib Holes

I use a Unibit chucked into a drill bit extention tool. Used correctly, the Unibit usually leaves a pretty smooth hole so I'm not sure what problems you might be having. I kept moving the drill from bay to bay, rechucking the extension tool to reach the next rib. Slowly but surely, you can work your way out to the tip.
 
Greenlee Knockout Punch

Your Unibit leaves burrs? Hm... Part of what's nice about the Unibit is that it "automatically" deburrs the drilling side if you just slightly push the next step into the work. Mine often leaves a little bit on the back side of the hole, but I use the edge deburring tool (swiveling hooked shape blade) to knock that down.

If you don't like the Unibit approach and want to blow some money on a high-quality tool, try a Greenlee knockout punch. You drill a 1/4" pilot hole on center, then tighten the male/female punch halves into each other, and it forms a perfectly round, perfectly clean hole every time.

knockout.jpg


I have a couple of sizes of knockout punches, but I got the 5/8" (0.625") punch to make holes for SB625-x snap bushings. I got some good use out of it making holes in seat ribs for wire runs -- after the plane was completed.

http://www.aircraftspruce.com/catalog/topages/knockout2.php

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
There are a lot of Greenlee punches on Ebay as well. Just be careful with the sizing. Apparently the size of the punch sometimes refers to the conduit size it was designed for. A 3/4" conduit punch makes a hole that is larger than 3/4". I hope that makes sense.
 
Dave, that does make sense.

The 1/2" cuts a 7/8" hole. That is because they are made for the electrical industry and the 1/2" pipe knockout is 7/8" OD. Electrical pipe is sized based upon ID.

BTW, being an electrician... I used the 1/2" KO punch and am threading 1/2" ENT (Electrical Non-Metallic Tubing) through the ribs for a conduit.

:cool: CJ
 
What size hole is drilled to accept the .810 dia flex conduit from Van's? I thought I read somewhere it was a 5/8 hole because that would let you thread the conduit through and keep it snug. It seems way to tight to ever get it inside the 5/8 hole though.

Jim Wright 90919 RV-9A wings Arkansas
 
rv9aviator said:
What size hole is drilled to accept the .810 dia flex conduit from Van's? I thought I read somewhere it was a 5/8 hole because that would let you thread the conduit through and keep it snug. It seems way to tight to ever get it inside the 5/8 hole though.

Jim Wright 90919 RV-9A wings Arkansas
Click to expand...

3/4" holes will keep the conduit plenty snug (and it's the size Van's recommends)--you'll still have difficulty pulling it through the holes. Good luck.
 
Conduit hole size

rv9aviator said:
What size hole is drilled to accept the .810 dia flex conduit from Van's? I thought I read somewhere it was a 5/8 hole because that would let you thread the conduit through and keep it snug. It seems way to tight to ever get it inside the 5/8 hole though.

Jim Wright 90919 RV-9A wings Arkansas
Click to expand...

I drilled 3/4" holes initially based on what it says on the Van's website (before I got the conduit). You can get the conduit through it, but pulling a length through the ribs is nearly impossible. I ended up drilling the holes out to 7/8" to allow me to pull it through the ribs. I'll put a dab of RTV or ShooGoo on it to keep it from chaffing.

Dennis Glaeser
7A Wings done - fuselage coming...
 
I'm not certain what the big concern is with Unibit. If they leave a little burr (which mind doesn't), just take a little emergy cloth and wipe it out.

One of these days, btw, it would be cool to get a section put together on some site some where with various wiring run ideas. It's clear the pass-through holes recommended by Van's are insufficient for the average task.
 
I think the uni-bit works great and leaves little to no burr. As Dan mentioned it tends to deburr the side your drilling from. I think the key is to use a high speed drill. A slower drill speed may tend to catch or grab the metal.

Bruce Smith
 
Two things.

To debur the other side of the hole just touch it with the unibit. Not enough to enlarge the hole but enough to take the burr away.

The second tip is at the top of my wing page. The pictures dated 8/18/05 show the simple little "tool" I made to locate the conduit holes in the same place on each rib.

Hope these help.
 
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