Deburring and dimpling bulkheads 7 and 8

Today I deburred and dimpled bulkheads 7 and 8, including trimming one piece per the plans. To trim the bulkhead, I used the step-drill on the drill press to enlarge a hole, then cut out some material with the bandsaw. Then I deburred the part, and then dimpled the flanges of all 4 bulkhead pieces.

I didn’t get any pictures tonight, not much to see. Next I’ll prime these bulkhead parts and rivet then together.

Deburring

Spent time tonight deburring the next couple of bulkheads. Not much to show, just scotch brite and sections of shiny aluminum. Hoping to have the next few bulkheads ready to prime this weekend.

Riveted aft bulkheads

Yesterday I worked on riveting the aft three bulkheads. Each of them are made up of several parts, including doublers.

I tried a few techniques to clamp parts, and to support the rivet squeezer. my first two rivets were perfect, but in the wrong holes! I got distracted for a minute, pulled out the wrong cleco, and set a rivet in the wrong hole. I set a second one before I suddenly realized my mistake. Fortunately I was able to drill and remove both without any damage.

Accidentally set two rivets in these holes. Drilled and removed them both.

I found it easiest to clamp the parts to the bench, with some carpet as padding, then hold the squeezer the two hands to set the rivets.

Clamping this way didn’t work very well. The parts were able to move and twist as the rivets were squeezed
Clamping to the bench with just the right tension worked better. Care taken not to bend the flanges by setting the clamps too hard

Today I was able to finish the job, the aft three bulkheads are ready to install now.

Aft three bulkheads are completed and ready to install

Drilled and Primed Bulkheads

Today I spent a couple of hours drilling and dimpling the aft bulkheads, and then a couple more hours priming several parts.

I used the drill block to match drill several holes from one of the bulkheads into the Vertical Stabilizer, the block was a huge help to ensure these were perpendicular to the bulkhead web. I was happy with how they turned out. Three of the holes will get final drilled to #12 and will take bolts that hold the vertical stabilizer to the fuselage. Any error in the hole orientation will effect the aerodynamics of the VS.

I needed to dimple the flanges of two bulkheads, but due to the angle of the flange, there is no way to get a female die on the inboard side of the flange. I have a spare squeezer yoke, so I cut off the end with a hacksaw, then ground it down to a small cross section. With the modified yoke, I was able to squeeze the dimples.

Modified yoke for dimpling angles flanges
Modified yoke clears the bulkhead web and the female die sits flush with the inside of the flange

In the evening I primed several parts for the aft bulkheads. The new hi-flow connectors made a significant difference. I used less paint, and the finish was much better. The paint atomized into much finer particles, covering the parts more evenly. The compressor was working harder, and I had to wait for it to catch up a few times.

About to start priming the aft bulkheads

It’s hard to tell from the photos, but the finish is significantly improved.

Primed bulkhead. The finish is much improved with the hi-flow connectors

Air Hoses and Drill block

After a few days in Texas, I spent time tonight getting ready to drill some critical holes, and to prime some parts.

I picked up a drill block from Brown Tools and practiced using it on some scrap. Pretty straight forward, and makes it very easy to be perpendicular to the surface when drilling holes. This block is for #30, #40, #21 and #10 drill bits.

Drill block and scrap for practice
Practicing on scrap

I also swapped out my air hose connectors, replacing them with hi-flow fittings. I ordered all of these from Amazon. You can really see the difference in diameter of the connectors when comparing them to the standard connectors. I also replaced my air filter with a smaller in-line filter, and removed a few unnecessary fillings. The idea is to increase air flow through the paint gun, and to maintain pressure when the trigger is pulled. More air flow should result in a better paint finish. Hopefully will test this out tomorrow.

New air filter on paint gun
Old connector on left, new hi-flow connector on the right

Finally, I got my VS down and clecoed the bulkhead that will be match drilled. This is all set for drilling tomorrow.

Bulkhead work

I skipped ahead a little, as I’m waiting on a drill block to help with some of the drilling where alignment is critical. I worked on the F-01410 bulkhead; deburred, stepped-drilled a systems hole, fluted and dimpled the F-01410 bulkhead. Then I straightened and final drilled the 1/4 in holes in the F-01410C, then clecoed it ready for final drilling.

Then I clecoed the F-01411 Bulkhead ready for final drilling.

These two bulkheads will hold the horizontal stabilizer onto the fuselage, so there is a lot of reinforcing here.

Deburring bulkheads

I put in a couple of hours tonight deburring parts. Not much to report. It’s a straightforward process, but can be a bit slow going, especially where there are corners. I almost finished deburring the aft three bulkheads, but started falling alseep, so calling it for today. Of course most of these parts will need final drilling and then more deburring, but that is a relatively quick process.