Drilling Wing Rib Holes

mlwynn · #1 11-15-2005, 09:23 AM

Hi all,

I am about to start drilling holes for pitot, conduit, etc in my wing ribs. I am wondering how best to do that. Unibits seem to leave a lot of burrs. Cleaveland tools has a hole cutting set
http://www5.mailordercentral.com/cle...p?number=DBRB7
that looks like it would work well.

Thoughts?

Michael Wynn
RV 8 Wings
San Ramon, CA

f1rocket · #2 11-15-2005, 09:35 AM

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.

dan · #3 11-15-2005, 09:39 AM

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.

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/catalo.../knockout2.php

)_( Dan
RV-7 N714D
http://www.rvproject.com

Davepar · #4 11-15-2005, 10:01 AM

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.

Captain_John · #5 11-15-2005, 05:24 PM

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.

CJ

dan · #6 11-15-2005, 06:11 PM

Yeah, you guys are right about conduit sizes and knockout punch sizing. But...keep in mind that the sizing that Spruce uses on this page:

http://www.aircraftspruce.com/catalo.../knockout2.php

...refers to the resulting diameter of the hole being punched.

)_( Dan
RV-7 N714D
http://www.rvproject.com

rv9aviator · #7 11-15-2005, 07:05 PM

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

alpinelakespilot2000 · #8 11-15-2005, 07:23 PM

Quote:

Originally Posted by rv9aviator

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

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.

DGlaeser · #9 11-16-2005, 06:47 AM

Quote:

Originally Posted by rv9aviator

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

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...

RV_7A · #10 11-16-2005, 09:02 AM

I used a uni-bit and an extention from Averys. I used poly tubing from Aircraft Depot. Its thin walled and slid perfectly into the holes.
http://www.jeffsrv-7a.com/WINGS/05-07-30.htm