Monthly Archives: July 2015

Nearly ready to rivet rear spar (and a clean sweep)

I keep thinking I’m almost done with the rear spar, but there’s just a lot of nit-picking work to do.  Progress has been very slow for the last month.  I was sick over one weekend, spent time doing honey-do’s and cleaning for another weekend, and packed some things to ship to my Chicago apartment; but I finally got back to the shop.

First, I installed a new retractable air hose from Harbor Freight.  My old hose tended to get caught underfoot and it was pretty low quality (it was bundled with a small compressor for nailing flooring).  Now I have a nice retractable wall mount.

I had to final drill the doubler plates on the spars (and match drill 6 rib connector holes on each spar as well).  That went pretty quickly with a 1/8″ reamer and 1/8″ drill as appropriate.

Then I had to countersink the spar over the double plates.  Pretty quick and easy as well.

Then countersink two rows of rivets in the end doubler plates.  It seemed pretty easy.  I used the countersink cage on a drill press and a small sample dimple plate to check the depth for the skin rivet rows.  I did the left plate and switched to the right.

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Then I started on the countersinks for rivets on the right plate.  Things seemed fine, but then something looked wrong.  The left plate is on the bottom and the right plate is on top.  They should be mirror images of each other.

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Surprisingly, no airplane parts flew across the garage, but I did realize that this is the kind of mistake that calls for walking away for a while.  I had to run to Home Depot anyway to get some wall patch supplies (more honey-do), so I stopped working rather early.  I ordered the replacement part and got it in time for the next weekend.

I got back to the shop, but really needed to clean up.  My sister-in-law is coming for a visit with her husband and young kids.  The shop was a bit too messy for short visitors, so I straightened things up and got behind the broom for a while.  It looks a lot better.

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Then, back to work!

The first thing I noticed when I clecoed the plate to the spar reinforcement fork was that the fork was upside down.  That’s why the holes were on the wrong side of the doubler plate.  I’m really glad that I stepped away.  If I had pushed on, I likely would have riveted the fork on upside down and would have had dozens of rivets to drill out!

I final drilled the new part from the reinforcement fork through to the new plate to make sure I had good alignment.  I finished the countersinking (after checking placement three times). Some quick filing and ScotchBrite and primer and I was back up to speed.

There was still a lot of work.  I had to disassemble the spars and deburr the new holes.  I also had to dimple the long flanges on the top and the bottom.  I did a couple with my vice-grip dimplers and decided that the DRDT-2 was a better option.  It was faster, but left blisters on my hands from all the dimpling action.

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I got both spars set up for riveting, but wanted enough time to be careful, so I marked the NO RIVET columns (for the ribs) with orange tape and called it a day.

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Next up, I will rivet all the doubler plates to the spars (skipping the ribs!), use a drill press to final ream the 3/8″ bolt holes at the end of the fork (the holes are 7/16″ at the moment), and rivet the spars to the ribs.

After that, the wing walk and top skins beckon.