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Can anyone offer advice on wing rigging. I had to build new blocks and attachment angles when I ruined my first attempt to drill. I had bought the McMaster-Carr step drill bit but did not use it. The .372 AN6 bolt dropped into the .375 hole and slopped around.

I tried to use straight bits to .371 and finish a .372 reamer. It didn't work. I have now up drilled everything to 1/4 inch and need to find a supplier for a piloted bit that is .372. Does anybody know where to find that piloted bit?

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Hey kwx2x2,
I am a huge believer in the piloted wing bushing technique. Here is my thread:
viewtopic.php?f=39&t=578&start=770

I know at least one builder messed up a couple sets of wing blocks and switched to this technique.

I used adjustable readers to sneak up on the final size. You can buy the set you need from grizzly industrial for less than $60.

http://www.grizzly.com/products/7-pc-Ad ... DQodJj8JAw

Keith
#554

I don't know if the .372 drill bit you're after is readily available, you might have to get it machined if that's what you want.
Most people have used the McMaster 3.75 piloted bit or gone with the method Brian has mentioned. In either case I don't believe reamers are used, just standard size drill bits.

One other option you have is to get a set of close tolerance bolts instead of the standard AN6 bolts.
AN176-XX would be the close tolerance AN6-XX equivalent.
For an AN6 bolt, the min/max diameter is .371/.374. The corresponding close tolerance (AN176) bolt,has a min/max diameter of .3737/.3742.

Bryan Cotton wrote:Hey kwx2x2,
I am a huge believer in the piloted wing bushing technique. Here is my thread:
viewtopic.php?f=39&t=578&start=770

I did the same. Start at this link,then move forward:
http://www.mykitlog.com/users/display_l ... 338&row=23
Much is described here:
http://www.mykitlog.com/users/display_l ... 948&row=16

The same technique would work with a larger (upsized) set of holes.

I used a 0.3725" reamer for my last pass.

All really good info. I already have the blocks and fuselage attach angles up drilled to 1/4. I think that Brians piloted bushing technique has got to be the best process. I was not aware of the AN176 so I will look into that and may use my McMaster step bit. The adjustable readers may also be a workable alternative. Thank you guys for offering up some different ideas that I was not aware of.

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I think Steve from downunder came up with the idea, I just stole it. I did not use an adjustable reamer, but one like this:
http://www.ebay.com/itm/170867521865

My drill bushings are available as part of the Sonex tool loan program. No takers yet.

My forward and aft fuselage attach angles are already up drilled to 1/4.

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The step drill I had was a couple of thou to big. Mentioned it to an Engineering friend of mine, he told me to hold a flat grinding stone on the edge of the bit whilst the bit was spinning in the drill press. With nothing to lose I tried it. Came out perfect. (Try it on scrap first)