Rear spar hole drill jig

[wirejock]

Does anyone know if this drill jig or similar is available?
http://www.vansairforce.com/communit...00&postcount=4

I'm researching and a jig and reamer seems like good idea. From what I've read sweep seems to be a bigger issue than incidence. Either way, there's vary little room for error drilling the rear spar. A jig would hopefully prevent drilling a crooked hole and busting an edge distance.
There's still lots to do but this is one operation I don't want to mess up. My rear spars are trimmed per plan and I put a flush rivet in the skin where the spar may touch. Hopefully all is as it needs to be (fingers crossed). Planning ahead.

[pilotkms]

I rented it 2 years ago. Worked as advertised. Worth the $$$$
It's from vince or terry in Las Vegas. I have seem them active recently here on the forum. Contact them at www.eaa1300.org

[Kyle Boatright]

A block of wood with a properly drilled (perpendicular) hole in it works well in that application. Align the wing and spar, mark where the hole should go, clamp the wood block to the spar so the hole is over your mark, drill the hole.

[N941WR]

Originally Posted by Kyle Boatright

A block of wood with a properly drilled (perpendicular) hole in it works well in that application. Align the wing and spar, mark where the hole should go, clamp the wood block to the spar so the hole is over your mark, drill the hole.

That's what I did. I used a 3/4" piece of oak and drilled a perpendicular #30 hole in it using my drill press. After marking the spot on the spar, I partially drilled a #30 hole halfway through the first aluminum bar. Then slid the drill block on a 12" drill bit. The end of the bit was put in the partial hole, the block slid down the bit to the spar and clamped in place. The #30 hole was drilled through all three bars. Once the block was removed, I used multiple drill bits and lubrication to get close to the final size. I used a reamer to bring the hole to the final size.

Once you have a pilot hole, subsequent drills and the reamer will follow that hole.

[Kyle Boatright]

Originally Posted by N941WR

That's what I did. I used a 3/4" piece of oak and drilled a perpendicular #30 hole in it using my drill press. After marking the spot on the spar, I partially drilled a #30 hole halfway through the first aluminum bar. Then slid the drill block on a 12" drill bit. The end of the bit was put in the partial hole, the block slid down the bit to the spar and clamped in place. The #30 hole was drilled through all three bars. One the block was removed, I used multiple drill bits and lubrication to get close to the final size. I used a reamer to bring the hole to the final size.

Once you have a pilot hole, subsequent drills and the reamer will follow that hole.

Excellent refinement.

In my experience, drilling a perpendicular hold isn't a problem. I know of several airplanes where edge distance was missed or the incidence or sweep wasn't correctly measured, causing a LOT of rework or an out of rig airplane.

This is one of those times in the build to slow waaay down, triple check everything (sweep, incidence, edge distance), have an experienced builder verify your measurements, then drill.

[N941WR]

Originally Posted by Kyle Boatright

...

This is one of those times in the build to slow waaay down, triple check everything (sweep, incidence, edge distance), have an experienced builder verify your measurements, then drill.

Good point!

After setting the incidence, sweep, etc. I walked away. I rechecked everything every evening for a week before I drilled the holes.

TAKE YOUR TIME and don't mess this up!!!

[wirejock]

Thanks for the replies and advise.
I'm doing my research trying not to mess something up.

[aviationone]

This will get you to a 3/16" hole. from there I used step reamers to get to final size. End product is a straight clean hole.



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