05-27-08 - Left Aft Spar

Getting ready to drill/cut/file the hole for the aileron pushrod. I've already laid out and drilled the rib attach holes with the metal template I used on the right aft spar.

Starting the hole with a unibit. The more metal I can remove the faster the better...

I used my manual nibbler to open up the hole more. Now for a bit of filing and sanding...

Filed to the sharpie marks. I'll clamp the doubler plate on to use as a pattern for final sanding/filing.

The hole final sized.

The hole before scotchbriting.

Polished with sand paper (120 grit) and then the fine (maroon) scotchbrite. I got a case of them from McMaster-Carr for like $20. They aren't 3M but are made by Norton. Same product, much better price.

An overall shot of the doubler hole.

Verifying the lenght of the spar channel for cutting. As usual I clam the tape on the 1" mark so I don't rely on the clip on the end. The rivets are loose and allow the tape to move almost an 1/8th

The mark is right on the money. So are all of the rib locations.

Cutting the corner of the channel with the hack saw to avoid tearing it with the snips.

Cut to lenght with the snips.

Filed and scotchbrited.

Here I'm match drilling the channel to the attach plate.

Match drilled to #40.

Using the unibit to cut out the flap pushrod hole. Same process as the aileron.

Again I used the laser cut kit part to file the hole in the channel to the correct size.

Match drilled and ready to cut the angle to match.

The angle for the left spar gets spaced .025 from the edge of the channel to align the edge of the rib with the skin. I used a peice of scrap to get the angle in the correct place.

Perfect - albeit a bit fuzzy.

Marked for the holes in the bracket. I'm going to match drill on the drill press to get the holes straight.

I supported the channel on the bandsaw and leved it up. The drill press table is perpendicultar to the bit and I've leveled the saw.

Perfect.

Match drilled to #40. The .025 space is there - just not visible in the resized picture.

Preparing to drill to #30.

I checked with my scrap just before drilling. Clecos aren't precise clamping devices.

The center holes drilled to #40. Unlike the right side spar they will stay this size.

Updrilling the holes for the AN3 bolts.

To ensure a tight fit hole as called out in the plans I used a reamer.

#12 is perfect for an AN3 bolt.

Just need a spacer now to keep the bolt head off the inside corner of the angle.

The second bolt hole reamed to #12.

Drilling the rest of the holes up to #30 for rivets. The holes with masking tape over them are to keep me from updrilling them before matching them to ribs.

All drilled to #30 (except for the ones that aren't)

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