Horizontal stabilizer assembly #2

Riveting step 1: riveting web-assembly

After test filling, I began riveting the stringer-web assembly together which is the framework that connects the front spar to the rear-spar in the center section of the stabilizer. Overall this was just a matter of squeezing the universal head 470-4 rivets. I found that four of the rivets in the corners were difficult to squeeze, so I used the offset rivet set and bucked them.

The stringer web assembly is then clecoed and to the front spar with the HS-1004 inspar ribs and the HS-904 ribs. I riveted the easily accessible 470-4 rivets with the squeezer and bucked the rivets in the corners which were harder to access with the squeezer.

Riveting step 2: nose-ribs to HS-00901 skin

Before the front spar was placed, the inside front ribs were riveted to the skin. I used the mushroom set and my tungsten bucking bar. This was the most challenging riveting of the project because of the difficulty placing the bucking bar and the rivet gun at the same time. I was mostly successful with a few rivets having slightly slanted shop-heads due to misalingment of the bucking bar.

After bucking the front nose ribs, I installed the front-spar assembly and began clecoing the ribs into place. At this stage, I spent a lot of time checking all the gaps between the skins and flanges. I found that a few of my countersinks were a little shallow causing a large gap or bulge between the skin and the flange. I decided to pull the skins off and add a few more thousandths to the countersink depth.