And Still More Dimpling and Countersinking....

Another long day dimpling and countersinking a myriad of elevator parts. The multiple small E-1008 ribs and both front and rear spars to name a few. Every part needs to be clamped to the workbench which slows the process down some. Dimpling with the squeezer normally goes pretty quick but countersinking a row of holes is a slow process. I've found that even with the microstop cage set up correctly every hole needs to be measured for correct depth due to all the variables involved. The tolerances are too tight to eyeball and there are bad consequences for drilling too deep or not enough. I had to countersink the rear spar where the trim tab hinge goes. The two pieces totaled .072" thick and I needed a countersink at least .040" +/- .002". Any shallower and the overlying dimple won't nest flush. Any deeper and the rivet shop head starts to be compromised because the material is too thin. It didn't help that the spar flanges are set at 84 degrees to the spar web so a jig had to be set up to hold the work surface flat and level.