Used to locate pre-drilled holes in the wing ribs, fuel tank covers, panels, skin. Pre-drill the ribs, screw in the back markers, lay the skin sheet over the top, tap with hammer, turn the sheet over, and drill the holes. This is especially useful for rivetnut installation.Due to the large size of the hole required, small errors in location can lead to the "Oh darn, I missed the rib syndrome". Backmarkers save you hours of frustration. 2 sizes of threaded backmarkers are available. Drilling the wing ribs with a 3/32" drill. Drop in the back markers.
Mark the skin by taping with a soft hammer. Turn the skin over and drill the skin with a 3/32" drill. Cleco the skin into position enlarge the holes with #30 drill & cleco.
*THESE BACKMARKERS ARE RIBBED (THREADED). OTHERS ARE PLAIN.
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