WXB F-12 UPPER LONGERONS

[wingnut99]

Anyone have a idea how to debur WXB F-13 upper longerons inside the tubing? Either there's a secret I'm not aware of or you just rivet the skin in place and hope for the best. I was able to file the gusset holes through the slots but nothing else.

[Spaceman]

Either there's a secret I'm not aware of or you just rivet the skin in place and hope for the best.

Pretty much the second one for me. I used to have a tool like this which would work for those longerons, but I broke it a long time ago and never bothered getting a new one:
https://www.yardstore.com/texas-in-out-deburr-tool-1-8

[Bryan Cotton]

Check out my post from December 6 of 2014:
viewtopic.php?f=39&t=578&start=360

It's down the page somewhere.

[peter anson]

One type of Noga deburring tool has a hooked blade which can be used on the blind side of a hole. For an example see https://www.blackwoods.com.au/tools-cutting-threading-carbide/deburring-tools/deburring-blades/blade-deburring-noga-n3/p/03849152. They work OK if the burr is not too bad.

Peter

[Rynoth]

I used this type of tool to deburr the backside of holes. The hooked blade in particular.

https://www.aircraftspruce.com/catalog/ ... s90061.php

[Mel]

I used this type of tool to deburr the backside of holes. The hooked blade in particular.
https://www.aircraftspruce.com/catalog/ ... s90061.php

Been using a tool like this for many years. It will be invaluable throughout the build.

[Spaceman]

Another way to do it is if you have a piece of steel bar laying around that would fit inside that square tube, you can use that to pretty much scrape the burrs off the inside surface. That's kind of what I did and it sort of worked. The correct tool definitely works better!

[thomas]

Pretty much the second one for me. I used to have a tool like this which would work for those longerons, but I broke it a long time ago and never bothered getting a new one:
https://www.yardstore.com/texas-in-out-deburr-tool-1-8

I'm happy with the following process for all my rivet holes in the thinnest of sheets up to the thick spar caps. I hardly ever use a #30 drill anymore:

1. if pilot hole is not prepunched, pilot with a #40 drill as usual

2. updrill with a 1/8" spiral flute HAND reamer (not a chucking reamer). The taper at the tip of the hand reamer centers nicely in the #40 hole and these reamers leave no break-through burrs. I've built both wings using a single $15 HSS reamer that is sold here: http://www.msdiscount.com/columnar.aspx ... y_site=WTL

3. disassemble parts and lightly break the edge on both the front and back side of each hole in one pass with the Texas 1/8" tool that Spaceman referenced.

This process is fast and gives me very consistent deburred holes without losing strength in those thin .025" sheets from a heavy chamfer.

Paul

[wingnut99]

Thanks for everyone's help. Bob Mika said he glued sandpaper to a stick and got pretty good results, so I ripped a 4' piece of 3/4" x 3/4" pine down to 5/8" x 5/8" and hot glued some 180 grit sandpaper to one end on one side and ran it back and forth from each end several times. It was snug enough to get decent friction and lot's of fragments fell out. Seemed to work pretty good. Kinda like running a cleaning brush through a shotgun bore. Not a bad idea.