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drilling / punching holes for conduits

oren_rokach

Well Known Member
Hi Guys
I am routing the conduits from tailcone forward through the fuselage.
My fuse is QB, so ribs are already rivetted to spars / bottom skin.
Running the conduits requires drilling 7/8 hole in the Fuse ribs, but since those are already installed, I having a hard time understanding which tool can do it?
I bought a 90deg drill extension to connect with unibit, but its too wide.
Have looked at pneumatical punchers, but they won't fit either.

Any ideas?

Thanks
Oren
 
I think a chassis punch would work. You'd still have to drill the (3/8"?) pilot hole, though. The other option would be to start at one end with the Unibit and keep adding extensions to get to the other ribs. You can get extensions up to 6' long (?).
 
Another option in lieu of drilling conduit sized holes is to route the conduit through the existing lightening holes in the ribs by fabricating little brackets with a conduit sized hole on one end and a screw/bolt holt on the other. That way you just need to drill a screw/bolt hole into the rib flange which is an easier proposition.
 
A step drill and an extension will do the trick.
(Yup: put tape around the drill bit so you know how far to drill.)

Of course, I drilled my ribs before riveting the wing together.

There are details on the 8/18/05 entry of my website .
 
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A step drill and an extension will do the trick.
(Yup: put tape around the drill bit so you know how far to drill.)

Of course, I drilled my ribs before riveting the wing together.

There are details on the 8/18/05 entry of my website .

Bill I think the problem Oren is running into is in the rear cabin (baggage floor and rear seat ribs) and not the wings. As the floor ribs are already installed he’s having difficulty getting a tool between the narrow rib spacing in order to drill the hole.
 
Bill I think the problem Oren is running into is in the rear cabin (baggage floor and rear seat ribs) and not the wings. As the floor ribs are already installed he’s having difficulty getting a tool between the narrow rib spacing in order to drill the hole.

My conduits use the existing lightning holes there. At the very rear, I made a plate with holes for the conduit that rivets over the last lightning hole. This holds the rear of the conduit captive. Just need to drill holes in the seat floor (behind pass side panel) at the front. Could also terminate with holes above rear spar under the flap covers. Snaking conduit in the floor rib lightning holes may not be possible if the floor sheets are on already. My conduit from the battery area to the tail uses lightning holes with a few tie wrap straps. No meaningfull drilling.

Larry
 
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Oren, are you trying to drill lateral holes in the F-1017 ribs? That is a tight area.

I think I used a greenlee punch in that area.

Another option would be to drill a pilot hole so the first notch or two on your step drill will fit, then use the step drill to enlarge the hole. Even if you start the hole off-perpendicular, as the bit penetrates farther and farther, you'll have more room to work between the ribs and can get the drill perpendicular before drilling to final size. If you look around, you can find stubbier step drills which will aid this process.
 
Bill I think the problem Oren is running into is in the rear cabin (baggage floor and rear seat ribs) and not the wings. As the floor ribs are already installed he?s having difficulty getting a tool between the narrow rib spacing in order to drill the hole.

Yep, I reread the post, my mistake.
 
holes

If you are attempting to drill the holes laterally and run the conduit along the fuselage and over the spar, remember you will have two 90 degree turns...and that can make pulling the wires more of a challenge, especially with corrugated conduit.

Ask me how I know...
 
F-1017A-R below rear seats rib penetration

Sorry guys,
I wasn't clear,
We have run the conduits under the baggage area easily :
https://eaabuilderslog.org/showmy.php?p=7YG7NRUc3&z3=&i=1876541&l=64882&t=m&f=20200103_103347.jpg

Now, I have to make a 90 turn towards the side , through F-1017A (thank you Kyle), and indeed no tool can be used there

I guess at least 50% here are QB , so I presume I missing something, will try with a 90deg drill to enlarge till the unibit fits, but it seems a far fetch.

Is there some unibit that can be attached to ATS tool:
https://aircraft-tool.com/shop/detail.aspx?id=ATS6132&AspxAutoDetectCookieSupport=1

thanks!
Oren
 
Oren, are you trying to drill lateral holes in the F-1017 ribs? That is a tight area.

I think I used a greenlee punch in that area.

Another option would be to drill a pilot hole so the first notch or two on your step drill will fit, then use the step drill to enlarge the hole. Even if you start the hole off-perpendicular, as the bit penetrates farther and farther, you'll have more room to work between the ribs and can get the drill perpendicular before drilling to final size. If you look around, you can find stubbier step drills which will aid this process.

https://www.amazon.com/Greenlee-7238SB-Slug-Buster-Knockout-Ratchet/dp/B000LDGN5C

Yep!!
That's seem like something that will do the miracle!
Hope I will find something at 1/5 of the price at ali-express :)

Thanks!
 
WAIT!

I own that cheap set...and wish I didn't.

The sizes CLAIM to be in inches but they are NOT.

Not quite sure what they are as they don't really match metric sizes either. I think it's probably just, well, cheap manufacturing.

I will also tell you that the tolerance between the punch and die is really sloppy. When I used them on a thin piece of aluminum (025), they did not shear the metal; it was torn, leaving the hole unusable.

This set might work for light gauge steel but I definitely WOULD NOT recommend it for light aluminum...

Spend the money and get the Greenlee set; you will never need to replace them...
 
Hi Guys
I am routing the conduits from tailcone forward through the fuselage.
My fuse is QB, so ribs are already rivetted to spars / bottom skin.
Running the conduits requires drilling 7/8 hole in the Fuse ribs, but since those are already installed, I having a hard time understanding which tool can do it?
I bought a 90deg drill extension to connect with unibit, but its too wide.
Have looked at pneumatical punchers, but they won't fit either.

Any ideas?

Thanks
Oren

Get a Greenlee Punch (or better yet, a set. You wont regret it).

Brian
 
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